All posts in Managing HD

Automated Navigation System Wheelchair for HD Patients

The parts of the brain most affected by Huntington’s disease (HD), the basal ganglia, are groups of neurons at the base of the brain. Basal ganglia are responsible for the motor movements of the muscles in the body. When cells in basal ganglia die, a common pathological symptom of HD, patients experience uncontrollable muscular movements like tremors and fallings. HD patients will need assistance of a wheelchair towards the end stage of the disorder when the movements become debilitating, and the falls become more prevalent. When they are unable to get up and move around on their own, wheelchairs become important mechanisms of transport.

An electric wheelchair by Dr. Yodchanan Wongsawat from Center for Biomedical and Robotics Technology Faculty of Engineering at Mahidol University in Thailand is designed specifically for disabled patients with limited hand mobility. This prototype wheelchair has an automated navigation system that could safely navigate and facilitate comfort to the disabled patients, including those with Huntington’s disease. The electric wheelchair accommodates a variety of conditions. If their hands are still functional, a patient could use their hands; otherwise, the modes can be operated by one’s chin or eye controls if the patient’s hands and chin are paralyzed or unable to function due to a debilitating movement disorder. These functions are explained further in details below. The wheelchair can be automatically navigated to the destination on the pre-located mapping. Moreover, through the automated navigation system, the obstacles can be detected and avoided safely.

The Automated Navigation System Wheelchair is made of these components:

  1. Rotating Laser Scanner: use for detecting the obstacles on the floor
  2. Laser Scanner: use for wheelchair localization, obstacle detection and mapping
  3. 7’’ LCD screen: come with user friendly interface together with command description
  4. Mini-PC: data acquisition and wireless communication device with server
Brain Control Wheelchair poster from BCI lab Mahidol, Download date 9/24/15

Source: Brain Control Wheelchair poster from BCI lab Mahidol, Download date 9/24/15

Brain Control Wheelchair poster from BCI lab Mahidol, Download date 9/24/15

Source: Brain Control Wheelchair poster from BCI lab Mahidol, Download date 9/24/15


Alternative Input Mode

  1. Eye Module
  2. Chin Module
  3. Hand Joystick Module
  4. Brain Module

Before initiating the automatic navigation task, the system needs to build a static map and define the users’ most frequent locations. These locations can be selected in the different choices of the automatic navigation mode. The information from odometers (which indicate distance traveled) and laser scanners are used for map building, which is based on a mapping technique, the enhanced simultaneous localization and mapping (SLAM) system. The most frequent users’ locations can be recorded, which is then used to build the static or a fixed map. In order to navigate the wheelchair from one location to the desired destination, the Robot Operating System (ROS) based navigation system will calculate a possible path using global path planning and control the wheelchair by the command velocity from the local path planning. During wheelchair navigation, the system can localize the wheelchair location by the Monte Carlo localization adaptive approach. The obstacles can be detected using the Tilt scanner. Once an obstacle appears, the ROS based navigation system can calculate a new path and safely continue navigating the wheelchair to desired destination.

Source: Brain Control Wheelchair poster from BCI Mahidol Lab, Download date 9/24/15

Source: Brain Control Wheelchair poster from BCI Mahidol Lab, Download date 9/24/15

Source: Brain Control Wheelchair from BCI Mahidol Lab, Download date: 9/24/15

Source: Brain Control Wheelchair from BCI Mahidol Lab, Download date: 9/24/15

In conclusion, the electronic wheelchair has many applications for HD patients, especially for those at the end stage of the disorder when the movements become debilitating, and the falls become more prevalent. This wheelchair is just a prototype and has not been mass-produced. However, individuals can order a customized version of it. For more information, please contact Dr. Yodchanan Wongsawat at




Extracorporeal Shock Wave Therapy (ESWT) for HD Patients Rehabilitation

The prevalence of pain in Huntington’s disease is unknown. An initial case report describes severe pain in two HD patients (Albin and Young, 1988). In a more recent study in 2010, eleven of nineteen HD patients had pain, with altered pain perception to pinprick, touch and temperature in some subject (Scherder and Statema, 2010). Exercise-induced muscle pain has been described in a marathon runner, who subsequently developed Huntington’s disease (Kosinski et al., 2007), suggesting that it may be an early unrecognized symptom of the disease. Significantly, there is a 10% to 25% prevalence of diabetes in patients with Huntington’s disease worldwide. Diabetes is a relatively common cause of neuropathic pain in a subset of diabetics.

Professor Areerat Suputtitada, M.D. is an expert on the use of extracorporeal shockwaves therapy (ESWT) on patients with pain management problems. She applies radial shock waves to the musculoskeletal system. The process involves producing high speed and high-pressure sound waves. The waves are delivered either in a focused manner, in which targets deeper tissues, or in a radial manner, in which targets a wider area. The energy is released to the tissues whenever there is a ligament to bone surface change.

Figure 1. Dr. Suputtitada Applying ESWT to Patient

Figure 1. Dr. Suputtitada Applying ESWT to Patient

Benefits for patient include

  • Outpatient treatment
  • No medication
  • No anesthesia
  • No surgery
  • No injections
  • Non-invasive treatment
  • Quick results
  • Improved quality of life

Benefits for the physician

  • Short application time
  • High patient acceptance
  • Broad range of indications
  • Outstanding product quality
  • Modular perfection
  • Low maintenance
  • Low cost

How does ESWT promote tissue healing in HD patients?

ESWT produces a strong energy pulse for a short period of time. The energy pulse breaks the sound barrier, which results in a shockwave. The shockwave from ESWT is identical, only on in a smaller scale, to the shockwaves that occur when a plane is flying faster than the speed of sound.

  1. The shockwave exerts pressure on the afflicted tissue. It increases cell membrane permeability and increases microscopic circulation to the tissues and the metabolism within the tissues, both of which promote healing and dissolution of pathological calcific deposits.
  2. “Cavitation bubbles” are small empty cavities created when shockwave is applied. The cavitation bubbles tend to expand to a maximum size, then collapse, much like a bubble popping. As these bubbles burst, a force is created. This force is strong enough to break down the pathological deposits of calcification in soft tissues and therefore reduce pain.
  3. ESWT stimulates osteoblasts or bone cells. These bone cells are responsible for bone healing and new bone production, so stimulating them enhances the healing process of bones.
  4. ESWT stimulates fibroblasts. Fibroblasts are the cells responsible for the healing of connective tissues like tendon or ligaments.

On a molecular and cellular level, ESWT also leads to complex interactions between the removal of neurogenic inflammation and release of growth factors, changes in gene expression, new bone formation and activation of mesenchymal stem cells, in which can differentiate into a variety of cell types like bone cells, cartilage cells, fat cells and muscle cells. All of these interactions then lead to pain relief and healing of patients.

In conclusion, ESWT is a noninvasive, easy to use after training, and cost effective way to improve quality of life within a short time frame. HD patients with pain management problems could consider ESWT. For more information on Dr. Suputtitada, her work on ESWT and her contact information, please refer to our spotlight article link.


Durant A, Millis D. Applications of extracorporeal shockwave in small animal rehabilitation. In: Millis DL, Levine D, editors. Canine Rehabilitation and Physical Therapy. 2nd ed. Elsevier; 2014. P. 381 -392

O gden JA, Toth-Kischkat A, Schultheiss R. Principles of shock wave therapy. Clin Orthopo Relat Res 2001; (387): 8-17

Borsook, David. “Medscape: Neurological Diseases and Pain.” Medscape. Medscape, 2012. Web. 22 Oct. 2015.


Cueing Device For Improving Gait Ability in Parkinson’s Disease and Other Motor Disorders

The parts of the brain most affected by Huntington’s disease (HD), the basal ganglia, are groups of neurons at the base of the brain. Basal ganglia are responsible for the motor movements of the muscles in the body. When cells in basal ganglia die, a common pathological symptom of HD, patients experience uncontrollable muscular movements. Another neurodegenerative disorder that produces similar abnormal movement is Parkinson’s disease, due to the disease’s effects on a specific area of the basal ganglia called the substantia nigra. Parkinson’s disease is a neurodegenerative disorder that results in characteristic motor abnormalities including postural instability and gait impairment. It consists of short shuffling steps, decreased walking speed, increased cadence, and gait freezing.

Current research is attempting to develop visual, auditory or somatosensory cues, or signals, to improve gait of Parkinson’s disease patients. Cueing device is defined as a device that uses external temporal or spatial stimuli to facilitate movement or gait initiation and continuation. The cueing device for improving gait ability in Parkinson’s disease was researched by Professor Areerat Suputtitada, M.D.,leading Physiatrist in Thailand. The main objective is to examine the effect of cueing devices using visual, auditory and somatosensory stimuli during walking in Parkinson’s patient using motion analysis. The study hypothesizes that the use of laser point, rhythmic sound and rhythmic vibration will increase the patients’ stride length, step length and speed, and decrease gait freezing.

Twenty Parkinson’s disease patients were asked to walk at a normal speed along a 10 meter walkway eight times using different combinations of cueing devices. The spatiotemporal data were recorded with motion analysis as seen in figure 1. The conditions tried include:

  1. Walking without a cueing device
  2. Walking with visual cue
  3. Walking with an auditory cue
  4. Walking with a somatosensory cue
  5. Walking with visual and auditory cues
  6. Walking with visual and somatosensory cues
  7. Walking with auditory and somatosensory cues
  8. Walking with all three cues.

All conditions were done three times by every patient.

Figure 1. Motion Analysis

Figure 1. Motion Analysis


The cueing device consists of 3 components (Figure 2):

  1.  Visual: used a laser pointer made from optic fibers with a switch to project the straight line
  2. Auditory: generated a rhythmic sound
  3. Somatosensory: used vibration and a microcontroller to create a rhythmic vibration
Figure 2. Cueing Device

Figure 2. Cueing Device


The researchers found statistically significantly better scores for gait freezing, step length and walking velocity in the patients group that used the cueing device compared to those who didn’t use the device. There was no statistically significant difference between each type of cues or combined cues. In figure 3, the left picture demonstrates short steps at baseline before the cueing device is used and the right picture shows an improved step stride when light and sound cues were used.

Figure 4. Before vs After Cueing Device Feet Scans

Figure 3. Before vs After Cueing Device Feet Scans


The study reveals the significantly effective use of visual, auditory and somatosensory cues for improving gait ability in Parkinson patients. The combined cueing device is a product designed by Professor Areerat Suputtitada,M.D. and her team. Although her team is using the cueing device to help patients with Parkinson’s disease improve their gait, it is also highly applicable to HD patients. For more information on Dr. Suputtitada, her work and her contact information, please refer to our spotlight article link.


  1. Suputtitada A, Sriyudthasak M, PongmalaCueing devices for gait ability in Parkinson patient using motion analysis. Gait & Posture 2009; 30 (Suppl 2): S127.
  2. Rochester L, Hetherington V, Jones D, Nieuwboer A, Willems A.M, Kwakkel G, Wegen E. The effect of external rhythmic cues (auditory and visual) on walking during a functional task in homes of people with Parkinson’s disease. Arch Phys Med Rehabil 2005; 86: 999-1006
  3. Suteerawattananon M, Morris G.S, Etnyre B.R, Jankovic J, Protas E.J. Effect of visual and auditory cues on gait in individuals with Parkinson’s disease. J Neurol Sci 2004; 219: 63-69
  4. Novak P, Novak V. Effect of step-synchronized vibration stimulation of soles on gait in Parkinson’s disease: a pilot study. J NeuroEng Rehab 2006; 3:9.
  5. Lim I, Wegen EV, de Goede C, et als . Effects of external rhythmical cueing on gait in patients with parkinson’s diease: a systematic   review.Clin Rehabil 2005;19:695-713.

Coping Strategies For Children Living With a HD Parent

The people most affected by Huntington’s disease are not only the patients with the condition but also the people around the person with the disease. This article focuses on the issues of children living with a HD patient.

Difficulties for Children

The majority of children who have a parent with a neurodegenerative disease, including HD, find it difficult to cope because they do not have the maturity and coping skills to deal with this complex situation. Often children are faced with

  1. Feeling Embarrassed

Having an illness in the family can make the child feel embarrassed or ashamed. The involuntary movements caused by HD tend to be distinct and patients with HD tend to be clumsy. This behavior can draw public attention because it is not immediately clear why the person is acting this way. Unwanted public attention and hearing upsetting things about their ill parent can cause a lot of confusion and anger.

  1. Stressful Household

Having HD in the family can cause a lot of stress as a result of increasing demands on the rest of the family members as the symptoms progress. The stress can also arise from the children being repeatedly separated from a parent that needs to be hospitalized for treatment or that is unable to provide consistent care. The eldest child may also have to grow up faster than other children because he or she has to act as a parent to the ill parent and younger siblings (This last point seems a little too circumstantial). An increase in stress may cause the children to feel insecure and anxious.

  1. Maltreatment and Abuse

In some cases, HD patients can become emotionally or physically abusive to family members as a result of the patients experiencing the behavioral symptoms of the condition. Some of the behavior changes as a result of HD that could manifest into abusive behaviors include aggression, disinhibition, hallucinations and mania. For more information these behavior changes, please refer to HOPES article on ‘The Behavioral Symptoms of Huntington’s Disease’:

When children of HD patients are faced with abusive situations a number of problems may arise. Often children will withdraw and isolate themselves as they develop feelings of anxiety faced with an unpredictable environment. These children may also find it difficult to concentrate on a task due to their anxiety levels. Children can also develop behavior problems when faced with situations and feelings that they are not prepared for. Children will often learn maladaptive behaviors and coping tools from their ill parent like temper tantrums, hitting, lying, bullying, and manipulation. Children may also feel anger or frustration due to their family situation, which can be exhibited in physical or verbal aggression.

How to decrease risk factors for the children?

  • Provide Knowledge

The most important thing a family member can do for a child that has HD parent is to educate the child about the disease. Children develop anxiety and worry when they observe unstable behaviors. Explaining to a child that a parent has these behaviors due to an illness may help the child empathize with rather than resent the ill parent. There are many resources for parents on how to talk to your children about HD. For more resources please refer to HOPES article on “Talking to Children About Huntington’s Disease”:

  • Provide a Stable Environment

It is often very difficult to provide a stable environment when one parent is unpredictable and schedules are continually being challenged and changed. However, it is important to try to provide predictability for a child and to commit to a routine. Children need a sense of routine to feel secure.

  • Seek Psychotherapy

Seeing a professional on a regular basis can be quite helpful to the child and all family members. Having a designated, impartial person to talk to and work out the issues with can be extremely beneficial. This can help children feel more supported and understood as they work through difficult feelings associated with having a parent with a neurodegenerative disease.

  • Nurture the Relationship With the Parents

It is important for children to have a positive connection with their parents. Often when a HD parent is unable to properly care for their child due to their symptoms, the relationship becomes strained. Children can become fearful or anxious around their ill parent and even feel unloved. It is important for the caregivers to make extra efforts to maintain the relationship between parent and child so that the child can grow up feeling secure and loved. When a child experiences instability due to a parent’s mental illness, it becomes important for the child to have appropriate role models. If a parent is unable to provide a sense of security for their child or to attend to their emotional needs appropriately, having a stable and secure relationship with another adult can help the child more easily be able to separate a parent’s behaviors due to the illness from negative feelings towards the child.

  • Healthy Peer Relationships

It is helpful for children to have healthy friendships with their peers. This allows them to develop trusting bonds and negotiation skills that will help them to cope with difficult times in the future. Interacting with their friends can help children of HD parents develop a more encompassing view of the world than they would have if kept isolated.

  • Foster Healthy Interests Outside of the Home

Often children of HD parents are not adequately socialized with peers and rarely have the opportunity to partake in sporting events or cultural activities on a regular basis due to lack of organization or chaos in family functioning. It is always important for children to develop their personal interests outside of the family in order to learn how to properly separate and develop a strong sense of identity and self. Children can also learn tools to cope with their daily environment and the stresses of living with a HD parent through the extracurricular activities.

In conclusion, as with any difficulty in life, having an HD parent is much easier to deal with once we have the tools to understand it and deal with it appropriately. With education and coping strategies, children with an HD parent can develop nurturing relationships with people in their lives.


Further Reading:

Brown University Child & Adolescent Behavior Letter, 18(7), 1. Leschied, A. W., Chiodo, D., Whitehead, P. C., & Hurley, D. (2005).

The relationship between maternal depression and child outcomes in a child welfare sample: implications for treatment and policy. Child & Family Social Work, 10(4), 281-291. Orel, N. A., Groves, P. A. & Shannon L. (2003).

Positive Connections: a programme for children who have a parent with a mental illness. Child and Family Social Work, 8, 113-122.


Eye Tracking Device for HD Patients

Eye tracking devices measure our eye behavior and predict our gaze points or the locations of the objects in space that we look at. The Eye Gaze System is an eye-operated communication and control system that empowers people with Huntington’s disease and other disabilities to communicate and interact with the world. By looking at control keys or cells displayed on a screen, a user can generate speech by visually typing a message or selecting pre-programmed phrases. Currently, this technology is being used to write books, assist education and enhance quality of life of people with Huntington’s and other conditions. Patients with Huntington’s Disease (HD) have poor muscle coordination and mental decline and behavioral symptoms. The eye-tracking device is especially useful for later stage HD patients when communication is a challenge.

Generally, the Eye Gaze System has a specialized video camera mounted below the screen. The video camera observes one of the user’s eyes and the image processing software analyzes the images sixty times per second to determine where the user is looking on the screen. A user operates the system by looking at rectangular keys or cells that are displayed on the control screen, which then activate. Through visual activation, the array of menu keys and exit keys allow the user to navigate the software independently. Through this eye tracking technology, users can operate lights and appliances remotely, control infrared devices such as televisions and stereos, surf the web and send emails, store and play music, organize and view photos and home movies, read books reading tablet, watch online videos, update social media statuses, and use a word processor to write down their thoughts.

For more sophisticated computer access there are several of the above-mentioned “eye gaze” computer systems on the market. Insurance will only fund an eye gaze system if the individual’s speech therapist can document that it is strictly necessary. Most insurance companies, including Medicare and some private insurance providers, will fund 80% of the cost of this device ( Producers of eye gaze systems include DynaVox (, Eye On (, LC Technologies (, Prentke Romich Company, (, and Tobii ( However, following Medicare guidelines, people enrolled in hospice or living at an assisted living facility are not eligible for communication devices.

Nevertheless, there are now other options on the market. Most are not fundable via insurance but some options can be found at a lower price. The Eye Tribe ( costs $99.00. This software enables eye control on mobile devices, allowing hands-free navigations of websites and apps. (It seems like this software has a different target audience – i.e. mobile phone users? Maybe you could say more about this?) The EyeWriter Project ( is a consumer assembled do-it- yourself kit with free blueprints and material costs at $100. This low cost, open source eye-tracking system allows patients to draw on a tablet using just their eyes. PCEye by Tobii ( costs 3,900. The technology replaces the standard mouse, allowing the users to navigate and control a desktop or laptop computer using only their eyes. Vision Key ( costs $4,000 and is the latest eye controlled communication that enables users to type and talk with their eyes. The system gives the users a voice by enabling them to control a speech synthesizer in the VisionKey unit or on the computer by looking at the screen. Users look at a specific word, letter or character on the chart in front of their eye and ‘type’ by holding their gaze until a selection is confirmed by a green highlight and a beep.

In conclusion, eye-tracking technology can be helpful for patients with HD or other disabilities. Eye tracking devices are especially useful for patients who have trouble communicating due to their conditions. The research into these devices continues to develop and as new technology emerges additions will be made to this list.


Potentials of Telehealth Devices for Speech Therapy in Motor Disorder


Rapidly evolving technology influences our daily lives. In particular information and communication technologies allow us to communicate faster and more globally than ever before. In this article, the possibilities of technological developments in healthcare, particularly for patients with Huntington’s disease (HD), will be explored. Patients with HD often struggle with speech intelligibility, a measure of how comprehensible speech is, or the degree to which speech can be understood., because as brain cells deteriorate in HD, problems may develop in the following three areas: motor control (movement); cognitive (thinking); and behavior. Speech and swallowing problems, due to muscle weakness and loss of coordination, arise when the motor control centers are affected. Cognitive problems include memory, sequencing, new learning ability and problem solving.

Telehealth and Speech Language Pathology

Telehealth is defined as the use of telecommunication technologies both to provide health care services and to enable access to medical information for training and educating health care professionals and consumers. Telehealth applications, could provide solutions to overcome barriers of access to therapy services caused by factors such as decreasing financial resources, shortage of professionals and increasing numbers of patients. Thus, telehealth concerns both mobile and computer’s applications of information and communication technologies, enabling the retrieval, recording, management and transmission of information to support health care.

Studies have suggested that online speech training for patients with motor disorder, specifically patients with Parkinson’s disease, turned out to be effective. In one study, ten patients used videoconferences during a four-week program of intensive training, involving 16 therapy sessions. Patients’ conversational monologue and prompted reading was recorded both before and after treatment Comparison of sound pressure level, pitch measurements and perceptual ratings from audio recordings revealed significant improvements. This study shows that remote diagnosis and treatment of speech in patients with motor disorder has vital benefits, in particular for patients who are less mobile and easily fatigued due to their deteriorated physical condition.


E-learning based Speech Therapy

Another study developed an E-learning based Speech Therapy (EST) in 2010. The therapy aims at patients with speech disorders resulting from acquired neurological impairment such as stroke or Huntington’s disease. Particularly in the chronic phase of the patients’ HD, once in-clinic therapy sessions are no longer an option, the lack of speech practice results in diminished speech. An important benefit of EST is to enable the patient to follow a specialized speech-training program in the patients’ home environment. Not only does E-learning reduce time energy and costs normally involved with speech training, the convenience the EST offers allows the patient to attend more therapy and practice speech could often lead to better speech outcomes.

A case study that evaluated EST included 20 patients with Parkinson’s disease suggests that EST is indeed a powerful web-based speech training device with potential efficacy for patients with movement disorder. The patients had completed face-to-face sessions with speech therapist and were able to conduct the training program that the patient was already familiar with, independently. The patients’ speech intelligibility had significantly improved as measured by the percentage correctly transcribed words given to the patient in a random sequence. After 4 weeks without practice, the patient’s speech intelligibility declined. Thus, while EST is a powerful tool, patients must also practice speech or continue with EST lessons in order to maintain speech quality.

In conclusion, these studies show that Telehealth devices can significantly improves speech intelligibility in patients with Parkinson’s disease. This finding is relevant for patients with HD because patients with HD also face troubles related to speech intelligibility. With this in mind, hopefully there will be more development in Telehealth devices that further can improve the quality of life HD patients.



If interested, here are some of the resources you can look into for telehealth devices on speech intelligibility.



Beijer, Lilian J., Toni C.m. Rietveld, Vera Hoskam, Alexander C.h. Geurts, and Bert J.m. De Swart. “Evaluating the Feasibility and the Potential Efficacy of E-Learning-Based Speech Therapy (EST) as a Web Application for Speech Training in Dysarthric Patients with Parkinson’s Disease: A Case Study.” Telemedicine and E-Health 16.6 (2010): 732-38. Web.

Bilney, B., M. E. Morris, and A. Perry. “Effectiveness of Physiotherapy, Occupational Therapy, and Speech Pathology for People with Huntington’s Disease: A Systematic Review.” Neurorehabilitation and Neural Repair 17.1 (2003): 12-24. Web.

Hill, A., and D. Theodoros. “Research into Telehealth Applications in Speech-language Pathology.” Journal of Telemedicine and Telecare 8.4 (2002): 187-96. Web.

Shelton, R. L. “The Genetics of Huntington’s Disease.” Perspectives on Speech Science and Orofacial Disorders 13.2 (2003): 7-12. Web.



A Case Study: Pregnancy and Symptomatic Huntington Disease

Although symptomatic HD patients are rarely encountered during pregnancy due to its late onset, the shift toward older maternal age means doctors will more likely encounter pregnant patients with HD. A search of the entire PubMed literature from January 1966 to August 2007 yielded 203 reports focusing mainly on prenatal diagnosis and counseling among healthy individuals at risk for HD. However, none of these reports focused on care issues relevant to our patient with a pregnancy complicated by advanced HD. This article therefore describes the illustrative complicated course of the patient, whom despite the complications, are able to deliver a successful birth with the support of relatives and hospital care.

Case study: Department of Obstetrics and Gynecology (University of Alabama at Birmingham)

A 31-year-old white female was referred at 25 weeks gestation due to unplanned pregnancy. She had a 5-year history of symptomatic HD and was under the care of a neurologist. She had deteriorated significantly over the preceding year, with impairment of communication, swallowing, ambulation and cognition. She had an uncomplicated term vaginal delivery 2 years prior to the diagnosis of HD. She was wheelchair bound with chorea, appeared malnourished, and was on oral liquid dietary. Nevertheless, fetal growth and anatomy were normal.

At 30 weeks, she was admitted in preterm labor but arrested at a cervical dilation of 4 cm after she received pre mature labor suppression drugs and steroids for pulmonary maturation. Due to her diabetes insipidus, she developed an intense thirst despite drinking large amount of fluids and excreting large amount of urine. As part of her symptoms, she also had acute renal failure, elevated sodium level in blood, a free water deficit and an abnormal increase in the osmolality of the body fluids. After she was treated with desmopressin (DDAVP), she had a positive response. After giving birth, the doctors failed to wean the patient off her DDAVP and she was kept on a maintenance dose.

As a result of intractable dysphagia or discomfort in swallowing, her nutritional status deteriorated, enternal feeding or delivery of a nutritionally complete food directly into her stomach, duodenum or jejunum was recommended. Managing tube feeds prove to be difficult because of recurrent tube dislodgment and the patient’s aspiration pneumonia. Percutaneous endoscopic gastrosomy (PEG), or an endoscopic medical procedure in which a tube is passed into a patient’s stomach through the abnormal wall, was used to provide a means of feeding. However, the PEG was unsuccessful due to the distortion of the patient’s stomach and her inability to maintain gastric distention. Hence, the medical team used computed tomography-guided placement of a Dobhoff tube. Antibiotics and total eternal feeding were also initiated.

The patient also developed kidney inflammation due to bacterial infection. Nevertheless, she responded to appropriate antibiotics. At 33 weeks, she developed an inflammation of the fetal membranes due to a bacterial infection and labor was induced. She received epidural anesthesia and spontaneously delivered a male infant with the Apgar scores for physical condition of 8 out of 10. Her central line was discontinued 1 day after she gave birth because of suspected site infection. The patient responded to a broad-spectrum of antibiotics and the PEG tube was successfully placed 5 days after she gave birth and enteral feeds resumed. She was discharged after 12 days after she gave birth. The infant was discharged in good health at 1 month of age.


This patient highlights several issues important to pregnant women with impaired mental, autonomic and physical ability such as symptomatic HD patients. While involuntary movements are manageable, the patient’s difficulty in swallowing indicated terminal disease and significant risk for aspiration syndrome and death. Hence, counseling regarding pregnancy termination early in the pregnancy is reasonable. Although prenatal diagnosis is available, it is highly controversial, as termination of pregnancy is rare due to the late, adult-onset of the disease.

Although not applicable to the case study patient, preconception counseling, preimplantation genetic diagnosis could have reduced the risk of a HD affected offspring.

The challenges experienced with gastric tube placement in the patient made enteral feeding tube the only feasible option during pregnancy. Increased abdominal pressure, gastric deformation in pregnancy, sphincter and muscular dysfunction associated with HD, likely contributed to the risk for aspiration and the failed tube placement attempts.

Another challenge was the patient’s inability to communicate effectively, especially regarding painful contractions. Family support was also vital as they received education on examining contractions and assisted with nutrition, mobilization, and activities of daily living and decubitus ulcer prevention. Social work, nutrition and physical therapy services helped optimize this patient’s care.

Although there is no direct link between diabetes insipidus and HD, reports of reduced levels of hypothalamic neuropeptides in animal models of HD suggest an association. The episode of kidney inflammation may be related to the combination of pregnancy, restricted activity and muscular dysfunction of HD, which posed a higher risk for bacteria infection.

The successful result of the case study patient’s pregnancy was possible due to a multidisciplinary effort and strong family support.


Hoskins, K. E., A. T N Tita, J. R. Biggio, and P. S. Ramsey. “Pregnancy and Active Huntington Disease: A Rare Combination.” Journal of Perinatology 28.2 (2008): 156-57. Web.

Kotliarova, Svetlana, Nihar R. Jana, Naoaki Sakamoto, Masaru Kurosawa, Haruko Miyazaki, Munenori Nekooki, Hiroshi Doi, Yoko Machida, Hon Kit Wong, Taishi Suzuki, Chiharu Uchikawa, Yuri Kotliarov, Kazuyo Uchida, Yoshiro Nagao, Utako Nagaoka, Akira Tamaoka, Kiyomitsu Oyanagi, Fumitaka Oyama, and Nobuyuki Nukina. “Decreased Expression of Hypothalamic Neuropeptides in Huntington Disease Transgenic Mice with Expanded Polyglutamine-EGFP Fluorescent Aggregates.” Journal of Neurochemistry 93.3 (2005): 641-53. Web.




Lifestyle and HD: Table of Contents

Read more about lifestyle and HD!


Google Glass and HD

The part of the brain most affected by Huntington’s disease, the basal ganglia, are groups of nerve cells (neurons) at the base of the brain. Basal ganglia are responsible for the motor movements of the muscles in the body. When cells in basal ganglia die, a common pathological symptom of HD, a person experiences uncontrollable muscular movements similar to that of fidgetiness. Another disease that produces similar uncontrollable movements symptom is the Parkinson’s disease due to the disease’s effects on a specific area of the basal ganglia called the substantia nigra.

A new app for intelligent glasses, such as Google Glass, might make it possible to improve the gait of patients suffering from Parkinson’s disease.


Companion Animals and Health

When most people consider therapies, they often think of prescriptions and side effects. However, animal companion therapy is proving to be an effective means of improving well-being among patients. Many of the benefits of animal companion therapy can extend to patients and family members living with Huntington’s disease. This article highlights the physical effects caused by companion animals, as well as opportunities for taking advantage of this type of therapy.

The Physical Effect of Companion Animals^

Stress can have harmful effects on the body’s ability to cope with various health issues. Research consistently shows that exercise and meditation can help manage stress levels. More recently, the scientific community has begun to collect growing evidence that animal companions might have the same effect on the health of patients.

The presence of an animal alone can affect our emotions. Animals are often able to focus people’s attention in a way that is calming or de-arousing (Cirulli et al., p. 342). Since animals, especially dogs, respond with affection and generally pro-social behaviors, they can potentially serve as an “emotional bridge” within therapeutic contexts.

The physical health effects of a companion pet can range from everyday benefits to life-saving changes. Within the first few months of acquiring a pet, patients tend to have lowered risk for cardiovascular disease, increased chances of surviving myocardial infarctions, decreased need of physician services during stressful life events and a reduction in everyday minor health problems.


Many HD patients cite lack of familial support as a major problem. Companion animals could help mediate this gap as icebreakers, bridging people with the outside world and jumpstarting communication and social exchanges that can promote feelings of social integration. Research in nonhuman mammals suggests that oxytocin, a signaling molecule in the brain, helps to increase one’s feeling of reward during social interactions while also increasing bonding between individuals. Oxytocin also assists in responding to social stress for humans. In fact, interacting with a dog caused a significant increase in levels of oxytocin within the human, improving his or her ability to forge new social bonds.

Creating an animal companion relationship^

In the study, Animal-assisted Interventions as Innovative Tools for Mental Health, researchers state that dogs are the ideal animal companions. Over thousands of years of domestication, dogs have been “selected for characteristics that enhance their sensitivity to a wide range of human communicative signals, both visual and acoustic” (Cirulli, p. 341). Dogs develop complex communication systems with humans and are highly interactive. Additionally, dogs provide opportunities for physical, recreational, and social activities. They are easily trained to constructively work in different settings, which explain their use as Seeing Eye and rescue dogs.

HD patients who live in nursing homes are often under great duress, as institutionalization can result in a decreased quality of life and stress due to separation from loved ones. Dog-mediated interventions could improve communication and reduce loneliness and depression.

Furthermore, animal companions could also help children of families experiencing traumatic life occurrences. Animal companions have been shown to influence social, emotional, and cognitive development in children. Parents often report that an animal helps teach children about life events. Children who grow up with pets have an enhanced sense of empathy and responsibility, social status within the peer group, and higher self-esteem and self-confidence.

While the positive aspects of animal companionship seem numerous, there are studies that raise questions about the extent of this impact. Visiting dog programs do not consistently “improve mood, cognitive abilities or social interactions” (Cirulli, p. 344). This might indicate that perhaps longer-term, matched interaction is needed between animal and human to see any effects. In fact, saliva spits revealed that there is a time-dependent increase in behavioral results such as improvement in mood or social bonding, as measured by mood changes and cortisol levels. (Cortisol is a hormone often associated with stress. Long term interaction with animals has shown to decrease levels of this hormone, improving well-being.)

Adding Pets to the Home^

In summary, adopting a companion animal into a Huntington’s disease family or an institution housing HD patients might have marked effects on the well being of various participants. However, there are certain aspects to take into account when making the decision to add a family member to the home. To find more information about the logistics of adopting a pet, visit

If you are concerned with integrating a pet into family experiencing health difficulties, please contact Pet Partners, an organization dedicated to “improving lives through positive human-animal interaction.” Visit their website at

For Further Reading:^

1. Cirulli, Francesca, Marta Borgi, Alessandra Berry, Nadia Francia, and Enrico Alleva. “Animal-assisted Interventions as Innovative Tools for Mental Health.” N.p., n.d. Web. 14 Oct. 2013.
2. Bekoff, Marc, Ph.D. “Pets Are Good for Us: Where Science and Common Sense Meet.”Psychology Today. N.p., 23 July 2010. Web. 14 Oct. 2013
3. Allen, Karen M., Jim Blascovich, Joe Tomaka, and Robert M. Kelsey. “Presence of Human Friends and Pet Dogs as Moderators of Autonomic Responses to Stress in Women.” Journal of Personality and Social Psychology 61.4 (1991): 582-89. Print.
4. Health Benefits of Animals. Pet Partners, n.d. Web. 14 Oct. 2013. .

K. Powers


Advocacy: How to Get Involved

This article describes current advocacy efforts, including the Huntington’s Disease Parity Act, Compassionate Allowance List, and how these two types of documents affect the average Huntington’s disease family.

Advocacy, by definition, is the means through which an individual or group attempts to influence public policy. The Huntington’s Disease Society of America website states that advocacy, pertaining to Huntington’s disease (HD), is sharing your personal HD story, as well as asking elected officials to support efforts to “improve access to treatment, medical care and to find a cure.”

Huntington’s Disease Parity Act^

The Huntington’s Disease Parity Act would require the Social Security Administration to revise the disability criteria for those with HD, especially in terms of the language used to approve applicants for benefits. It would also waive the 24-month waiting period for Medicare eligibility for individuals disabled by HD. (To view the actual text of the bill, click here).

Many individuals experiencing symptoms due to HD are unemployed due to their disabilities. Because of this, they often rely on Social Security Disability Insurance (SSDI). SSDI is based upon the amount of income an individual was receiving when he/she became disabled. Payments often range from $500 to $2,000 a month. However, after qualifying for this insurance, the individuals must wait at least two years before receiving any benefits from the Medicare program. This policy is extremely problematic as many HD patients are under the age baseline for Medicare (65 years old), and yet deteriorate very quickly if symptoms aren’t addressed with proper medical care immediately after diagnosis.

The HD Parity Act would correct this problem by waiving the 24-month waiting period as it did for patients with amyotrophic lateral sclerosis (ALS) in 2000.  (This bill passed as an attachment to an appropriations bill after confirming an influential number of co-sponsors in the House and Senate.) In addition, the SSDI guidelines for HD are almost 30 years out of date, affecting who is approved for the insurance. These guidelines do not recognize the psychological effects of HD, which can appear 10 to 15 years before motor symptoms begin. In the SSDI guidelines, HD is only defined as Huntingtons Chorea, the uncontrollable writhing movements that characterize the motor disability of HD. Correcting the medical definition would make HD patients eligible for SSDI earlier and alleviate a lot of financial hardship. According to estimates by Strategic Health Care, this bill would only cost $10-13 million a year, which is a negligible cost for Social Security Disability payments.

Efforts are being made to promote the bill and ensure that it is approved. The bill has been introduced four times previously, and is on its fifth introduction in 2015. The bill was introduced into the Senate by Senator Kirsten Gillibrand in April 2015, and currently has 1 cosponsor. In this 114th Congress, this year, it has been introduced into the House of Representatives by Representative Adam Kinzinger with 103 original cosponsors (the highest starting point yet). Additional representatives, both Democratic and Republican, have signed on as regular cosponsors, bringing the tally up to 129. This level of support is important, because it makes the bill a higher priority. Since it is starting out at a stronger place earlier in the congressional session, it is easier for legislators to find opportunities to attach it to a larger piece of legislation that is on its way to get passed. Since its inception, the Huntington’s Disease Society of America has been encouraging its support by senators and representatives and has set a goal of obtaining 175 co-sponsors.  However, this goal is flexible as it is ideal to have a majority of Congress support this initiative.  The more senators and representatives in support of this bill, the more likely it will be passed when voted upon.

To check whether or not your elected officials have supported this act, click here.

Compassionate Allowance List Update^

SSA Announces Official Inclusion of Adult-Onset HD to Compassionate Allowance List

On Thursday, December 6, 2012, the Social Security Administration (SSA) announced that adult-onset HD would be added to the Compassionate Allowance List (CAL), along with Juvenile-Onset HD, which was added in April 2012.

The CAL allows those affected by diseases on the roster to enter a fast track for applying to Social Security benefits. This means families affected by HD will no longer face rejection and postponed benefits due to outdated definitions of HD symptoms.  According to the Huntington’s Disease Society of America, the addition to the CAL “also recognizes the cognitive and psychological symptoms of HD and establishes criteria for their use in the qualification process.”

While inclusion on the CAL is a great step forward, there is still a need for the SSA to update their outdated description of HD, which defines the disease as a movement disorder (especially since the CAL language refers back to the SSA definition). CAL will not address issues of insurance. It also does not affect the language used by the SSA which does not include the cognitive and psychiatric aspects of HD, arguably the more debilitating aspects of the disease and the first to appear. These issues, along with the 2-year waiting period for Medicare eligibility, are addressed in the proposed Huntington’s Disease Parity Act, which is currently in need of more co-sponsors in both the House and Senate.

If you are interested in advocating for the HD Parity Act, visit to write your senators and representatives, urging them to co-sponsor this important bill. Constituent involvement is important to elevate the importance that legislators place on the bill. Congress runs on stories from constituents; it is vital to put a narrative and a face behind the issue.

In addition, if you or someone you know affected by HD is denied disability, please contact Jane Kogan of the Huntington’s Disease Society of America. You can e-mail her at for support and advice on re-applying.

The Fast Facts: A Summary^

The Parity Act Fact Sheet is a quick guide to the basic facts concerning the Huntington’s Disease Parity Act. All of these facts were compiled by the Huntington’s Disease Society of America.

1. Huntington’s disease is the only disease that is neurological, genetic, fatal disease, and rare, yet strikes during one’s working years. It is also the only disease to potentially have total cognitive, motor, and behavioral impairment, all at the same time.

2. The Compassionate Allowance Act eases the wait time for disability insurance review. However, only the Huntington’s Disease Parity Act will update the language, allowing more people with the disease to qualify for disability benefits. That means less people will be denied disability coverage.

3. The Social Security Administration (SSA) has the power to change their definition of HD. Their neurological disability guidelines expired on July 1, 2012. SSA extended their own deadline to publish the new guidelines for an additional two years. Legislation would mandate they speed up the process.

4. The HD Parity Act has an expected $260 million cost over 10 years (starting after the removal of the two-year waiting period). These estimates are based upon the costs incurred by a similar act passed for ALS (amyotrophic lateral sclerosis) in 2000. The cost of removing the two-year waiting period for all diseases is estimated to be around $113 billion over 10 years (2008 Congressional Budget Office).

5. If this legislation were passed, Medicaid savings could potentially lower the total cost of this policy by as much as 20 percent, for a total annual cost of $21 million annually (Strategic Health Care). (Strategic Health Care, a lobbyist group for the HDSA, obtained these numbers from the independent research conducted by Mathematica Policy Research and the Congressional Budget Office.)

6. The support of 218 representatives from the House and 60 senators from the Senate is needed in order to pass a bill. (The Senate number would mean there would be no possibility for a filibuster (an attempt to block  a vote for legislation through methods such as speaking for extended periods of time). In addition, there do not need to be 60 official co-sponsors, but rather 60 Senators who have shown some level of support for the bill.)

7. Members of Congress do not need to sit on the committee of jurisdiction to co-sponsor legislation. Any member of Congress has the power to cosponsor a bill, no matter what committee they serve on.

8. Amyotrophic Lateral Sclerosis (ALS) and End Stage Renal Disease (ESRD) have both received waivers for the two-year Medicare waiting period through Congressional legislation.

Anyone can be an advocate for measures that would improve the lives of those affected by Huntington’s disease. Whether it be sending your representative an e-mail urging them to co-sponsor legislation or fighting discrimination in the workplace, everyone can make a difference.


Further Reading^

1. “Bill Text 114th Congress (2015-2016)S.968.IS.” Bill Text of the Huntington’s Disease Parity Act. Kirsten Gillibrand, n.d. Web. 29 April. 2015.


This is the text of the bill introduced to Congress. View it in its entirety by clicking here.


2. “Advocacy.” N.p., n.d. Web. 11 Dec. 2012.


This is the Huntington’s Disease Society of America’s official Advocacy website.

3. “SSA Announces Official Inclusion of Adult-Onset HD to Compassionate Allowance List.” Message to Kristen A. Powers. 7 Dec. 2012. E-mail.


This is an e-mail sent out by the Huntington’s Disease Society of America. To view the web version, click here.

KP 02/15/2013 LV 04/29/2015


Medical Marijuana Policy in the United States


Disclaimer: This article is meant to be purely educational—HOPES neither condones nor condemns the use of marijuana for medicinal purposes.

Throughout the past several decades the use of marijuana for medicinal purposes has received increasingly more attention.  The active ingredient in marijuana belongs to a class of compounds called cannabinoids, which have been used to treat numerous conditions ranging from insomnia and PMS to chemotherapy-induced nausea and appetite loss associated with AIDS therapy.  More recently, cannabinoids have been shown to be effective against motor disturbances in patients with multiple sclerosis.  This latter finding points to a potential use of medicinal marijuana to treat movement problems in Huntington’s Disease.



Weight Loss: Demystifying a Medical Mystery

While Huntington’s disease is traditionally thought of as a disease of the brain, its effects are much more widespread: many people with HD lose a dangerous amount of weight, complicating a disease that is already complicated enough. Although weight loss is one of the most serious non-neurological problems of HD, scientists don’t fully understand why it occurs. This medical mystery has driven scientists deep into the biology underlying weight loss in HD. Researchers have recently turned up a few potential explanations, and our increased understanding of this symptom is leading scientists to look at possible new ways of treating the disease.

Weight Loss in HD^

People with HD tend to weigh less than those without the disease. A group of researchers from the Huntington Study Group followed 927 people with early-stage HD. For a description of the stages of HD, please click here. The investigators found that people with early-stage HD weighed an average of 10 kilograms (22 pounds) less than age-matched controls, which are people of the same age who don’t have the disease. Another study found that people with HD lose an average of 0.9 pounds per year, which stands in stark contrast to the average American, who gains 0.4-2 pounds yearly.

Unfortunately, while 0.9 pounds doesn’t seem like much, that’s just an average; some people with HD lose so much weight that their health is impacted. Weight loss worsens other aspects of the disease as underweight patients become malnourished and weak. Underweight patients are more susceptible to infection, and take longer to recover from illness, operations, and wounds. Weight loss also increases the likelihood of developing pressure ulcers, commonly known as bedsores, as bedridden patients have less fat tissue to cushion them from pressure. Patients who lose the most weight report a lower quality of life, and are more likely to feel apathetic and depressed. In the late stages of the disease, some patients lose so much weight that they need a feeding tube to stay healthy, as described here. On the other hand, people who start out heavier fare better; people who have a high body-mass index (BMI) when symptoms begin progress more slowly through the disease. Visit this website for an explanation of BMI and a for BMI calculator.

A Medical Mystery^

While weight loss is one of the most serious non-neurological problems associated with HD, doctors don’t understand why it happens. Many suggestions have been put forth, but most of them have been disproved, forcing researchers to dig deeper to understand this phenomenon.


Doctors once believed that weight loss was due to chorea, the uncontrolled movements characteristic of HD. Doctors thought that people with HD lost weight because they burned extra energy as a result of the involuntary movements of chorea. However, three experiments indicate that chorea can’t be fully responsible for weight loss.

The first piece of evidence comes from looking at the early stages of the disease. People who have just been diagnosed with HD – and therefore have very mild symptoms – already weigh less than people without the disease. As mentioned earlier, people in early-stage HD weigh an average of 10 kg less than those who are not affected by the disease. Another group of researchers arrived at similar results; a study of 361 people with early-stage HD found that they have BMIs an average of 2 points lower than those without the disease, even if the patients had just been diagnosed with HD within that year and hadn’t yet begun to experience choreic movements. Researchers concluded that chorea alone could not explain why people with HD have lower BMIs, and that other factors are at play.

Other studies suggest that chorea may not have as much of an impact as doctors once thought. Pratley et al. measured how much movement chorea caused, in an attempt to quantify how much weight patients lose due to choreic movement. After measuring the movements of 17 people with mild to moderate HD for a week, they found that chorea caused people with HD to move more than people without the disease when sedentary: people with HD moved 14% more than people without HD while sitting or lying down. However, people with HD do less voluntary activity. Study participants with HD walked around and exercised less than people without the disease. In the end, Pratley et al. were surprised to discover that sedentary over-activity balanced out voluntary under-activity: people in the early and middle stages of HD don’t actually move more than people without the disease.

A similar study by the European Huntington’s Disease Initiative Study Group (EHDI) measured weight loss in 517 people with HD, and found no correlation between the amount of weight people lost and the severity of their motor symptoms; people with good scores on tests measuring motor symptoms (such as the UHDRS) were just as likely to lose weight as those with bad motor scores. For more information on diagnostic tests like the UHDRS, click here.

The final strike against the chorea theory comes from observations of people with late-stage HD. Weight loss is most drastic in the final stages of HD, despite the fact that chorea has usually ceased and patients are largely bedridden. So while chorea contributes to weight loss in HD, it cannot stand as the sole explanation.

Reduced Food Intake^

Others suggest that people with HD lose weight because they have trouble eating; as the disease progresses, it becomes increasingly difficult to perform the complicated series of movements needed to eat, chew, and swallow.

However, this theory is also not enough to fully explain the weight loss. Studies have shown that people with HD actually tend to eat more than people without the disease; a study of 25 people with HD found that they ate an average of almost 400 calories more each day than people without the disease. Others report that they’ve had patients who eat up to 5000 calories a day – over twice the average daily caloric intake – just to maintain their weight.

So two popular explanations for weight loss in HD – chorea and insufficient diet – cannot entirely explain why people with HD lose so much weight.

Possible Biological Causes^

Though the reasons for the mysterious weight loss are unclear, scientists are currently testing a few ideas.

Abnormalities in Energy Metabolism^

One leading idea has to do with metabolism, the way the body burns calories to produce energy. HD researchers have long suspected that the disease-causing form of huntingtin (hereafter described as mutant huntingtin) interferes with energy metabolism, as described here. Results from a recent study suggest that this interference might contribute to weight loss.

After discovering that weight loss is not correlated with motor symptoms, scientists from the EHDI Study Group looked for other factors that might be to blame. They found that weight loss could be partially predicted by the number of CAG repeats on a patient’s copy of the mutant huntingtin gene; for every additional CAG repeat a patient had, they lost on average an extra 0.136 BMI points (0.8 pounds) over the course of the three year period that the study was conducted. For an explanation of CAG repeats, please click here.

The same holds true in mouse models of HD. The EHDI Study Group found that the more CAG repeats an HD mouse had, the more it tended to eat. Yet paradoxically, the mice with the most CAG repeats lost the most weight. So people and mice with more CAG repeats lose more weight.

The EHDI investigators suspect that this is due to the long tail of the mutant huntingtin protein. People with more CAG repeats produce mutant huntingtin with a longer tail, as described here. The EHDI investigators suggest that the mutant huntingtin protein interferes with the way cells make energy, and that longer-tailed proteins cause more problems. Mutant huntingtin has been shown to disrupt proteins that are needed to make energy and can damage mitochondria, the “energy factory” of our cells, as described here. In support of the theory that proteins with longer tails are more problematic, scientists at the MacDonald lab in Boston studied cells engineered to express mutant huntingtin. They found that cells with more CAG repeats made less ATP, the energy currency of the cell. So it seems possible that the more CAG repeats individuals have, the less efficient their cells are at converting calories to energy.

Hormonal Shifts^

A second school of thought suggests that weight loss is due to hormonal disturbances in people with HD. Hormones are the body’s chemical messengers, and are important for regulating physiological processes, like hunger. The hypothalamus secretes many hormones, so when HD causes cells in the hypothalamus to malfunction and die, hormone production is disturbed.


Some of the hormonal signals that the hypothalamus sends out go to the gut and fat tissue, and direct processes like eating and burning energy – processes that are very important in maintaining a healthy weight. Therefore, some scientists think that cell death in the hypothalamus causes hormonal changes that might contribute to weight loss and other problems such as sleep disturbances, as described here.

Dysfunctional Digestion^

Further insights have come from studying the way mutant huntingtin interacts with the digestive system. Certain symptoms of HD have hinted that the disease might affect the gut; apart from weight loss, people with HD often experience nutritional deficiencies, cramps, and wasting of skeletal muscles. People with HD are also prone to gastritis, a disease where the stomach lining becomes irritated or swollen.

Despite these symptoms, many HD researchers have traditionally thought that mutant huntingtin only affected the brain – a belief that struck some as strange because the protein is made and found throughout the body. However, results from a recent study suggest that mutant huntingtin in the gut might interfere with important digestive processes, thus contributing to weight loss.

In the study, van der Burg and colleagues looked at R6/2 mice, which are mouse models of HD described in greater detail here. They noticed several physiological changes that could all impact digestion. First, they noticed that the small intestines of HD mice were 10-15% shorter than those of normal mice, and that they had smaller villi, the tiny finger-like projections in the gut that take up nutrients. On top of that, scientists noticed that the mucus lining of the gut of the HD mice was 20-30% thinner. Since all of these structures are needed for nutrient absorption, these findings suggest that HD mice can’t take up nutrients as efficiently as normal mice.

Furthermore, the group found that the HD mice were missing a few key hormones that control the speed at which food passes through the body. This caused an increase in ‘transit time’: the food passed more slowly through the gut. Longer transit time might foster bacterial growth; if food takes longer to pass through the gut, harmful bacterial have more time and a better opportunity to flourish. This could make the small intestine irritated and inflamed, which could cause malabsorption of nutrients, chronic diarrhea, nausea, bloating, flatus, and weight loss. Those bacteria might also use up nutrients that the body would have otherwise taken up.

To see whether these physiological differences actually have an impact on digestion, researchers then compared the feces of HD mice to those of normal mice. They found that HD mice excreted more of what they ate, suggesting that they absorbed fewer calories and nutrients from their food. Notably, the mice that were the worst at absorbing nutrients from their food lost the most weight.

Van der Burg et al. had a few ideas as to what mutant huntingtin might be doing to interfere with digestion. Since the protein is present in gut cells, it could interfere with cell function and nutrient absorption. They also thought that mutant huntingtin might affect transcription, the process by which DNA is converted into protein as described here. If mutant huntingtin affects transcription in gut cells, it could cause a decrease in levels of important proteins needed for cells to survive and function properly.

While findings in HD mice don’t always translate to humans, these results indicate that scientists might benefit from studying the way HD affects digestion in people. Van der Burg et al. suggest that such research might help doctors improve their understanding of nutritional supplements for HD, and might even change the way we think about how people with HD metabolize and react to medicine.


Weight loss in HD has long puzzled doctors, patients, and caretakers alike. Two popular explanations of the phenomenon – chorea and reduced food intake – have been debunked as major contributors to weight loss. However, scientists have made new in-roads in recent years. By discovering that mutant huntingtin might disrupt energy metabolism, digestion, and hormones in HD mice, scientists have enhanced our understanding of HD, which may pave the way to new treatments and therapies. For example, the hypothesis that weight loss is linked to abnormalities in energy metabolism suggests that energy-boosting drugs – namely creatine and Coenzyme Q10 – are strong candidates to fight HD, as described in these articles here. Each further discovery about HD leads to a greater understanding of the disease, and brings hope for patients and families.


1.     Aziz NA, van der Burg JM, Landwehrmeyer GB, Brundin P, Stijnen T; EHDI Study Group, Roos RA. Weight loss in Huntington disease increases with higher CAG repeat number. Neurology. 2008 Nov 4;71(19):1506-13.

This medium-difficulty study describes how people with more CAG repeats lose more weight – and provides some theories as to why that might be the case.

2.     Djoussé L, Knowlton B, Cupples LA, Marder K, Shoulson I, Myers RH. Weight loss in early stage of Huntington’s disease. Neurology. 2002 Nov 12;59(9):1325-30.

This medium-difficulty article describes weight loss in people with early-stage HD

3.     Hamilton JM, Wolfson T, Peavy GM, Jacobson MW, Corey-Bloom J; Huntington Study Group. Rate and correlates of weight change in Huntington’s disease. J Neurol Neurosurg Psychiatry. 2004 Feb;75(2):209-12.

This medium-difficulty article describes weight loss in people with early-stage HD

4.     Kremer HP, Roos RA. Weight loss in Huntington’s disease. Arch Neurol. 1992 Apr;49(4):349.

This short, medium-difficulty column suggests that cell death in the hypothalamus could contribute to weight loss

5.     Petersén A, Björkqvist M. Hypothalamic-endocrine aspects in Huntington’s disease. Eur J Neurosci. 2006 Aug;24(4):961-7. Epub 2006 Aug 21. Review

This technical article describes how hormonal changes in people with HD might lead to weight loss

6.     Pollard J, Best R, Imbrigilo S, Klasner E, Rublin A, Sanders G, Simpson W. A Caregiver’s Guide for Advanced-Stage Huntington’s Disease. Huntington’s Disease Society of America, 1999.

This easy-to-read handbook is a very helpful resource for caregivers taking care of people in late-stage HD

7.     Pratley RE, Salbe AD, Ravussin E, Caviness JN. Higher sedentary energy expenditure in patients with Huntington’s disease. Ann Neurol. 2000 Jan;47(1):64-70

This study measured movements of people with HD, and found that their total energy expenditure was the same as that of people without the disease, and is somewhat technical

8.     Seong IS, Ivanova E, Lee JM, Choo YS, Fossale E, Anderson M, Gusella JF, Laramie JM, Myers RH, Lesort M, MacDonald ME. HD CAG repeat implicates a dominant property of huntingtin in mitochondrial energy metabolism. Hum Mol Genet. 2005 Oct 1;14(19):2871-80. Epub 2005 Aug 22.

This technical article describes how huntingtin interferes with energy metabolism in a CAG-dependent fashion

9.     Trejo A, Tarrats RM, Alonso ME, Boll MC, Ochoa A, Velásquez L. Assessment of the nutrition status of patients with Huntington’s disease. Nutrition. 2004 Feb;20(2):192-6.

This medium-difficulty paper discusses the result of the study on 25 HD patients that ate an average of 400 calories more than controls each day.


10. van der Burg JM, Winqvist A, Aziz NA, Maat-Schieman ML, Roos RA, Bates GP, Brundin P, Björkqvist M, Wierup N. Gastrointestinal dysfunction contributes to weight loss in Huntington’s disease mice. Neurobiol Dis. 2011 Oct;44(1):1-8. Epub 2011 May 23.

This technical article describes the impact of huntingtin on digestion in HD mice

M. Hedlin 11.16.11


Advance Directives

In the last stages of Huntington’s disease (HD), patients have difficulty thinking and communicating clearly, so decisions about their end-of-life medical care often fall to doctors and relatives. However, many people with HD have strong opinions as to how they would like their last years to unfold. Advance directives are instructions written by mentally and physically competent patients to convey their preferences about end-of-life medical care ahead of time. They are powerful expressions of a person’s wishes about their future health care. Anyone over the age of 18 is legally qualified to make these decisions for himself or herself. Health care professionals who are caring for a patient will refer to advance directives if the patient is unable to make or communicate their decisions later in life.

Advance Directives and HD^

Why are advance directives important for patients with HD? Because the age of onset and severity of HD symptoms are relatively unpredictable, sudden changes can quickly change the course of patients’ lives. During the end stages of HD, many patients are nonverbal and unable to communicate their wishes. Advance directives allow patients to decide their end-of-life care ahead of time so that their treatment fits their unique mental and emotional needs.

While it may seem like a simple task to address advance directives before late-stage symptoms occur, there are numerous obstacles that make it difficult for patients to make such decisions earlier in their life. These obstacles mostly fall into three categories: the doctor, the patient, and the patient’s family. Regarding doctors, there are currently no guidelines requiring doctors to discuss advance directives with patients early in the course of the disease. Thus, many doctors do not discuss end-of-life care with their patients when they are in earlier stages of chronic diseases. This greatly contributes to the difficulty of the decision process for the patient.

Patients themselves may exhibit cognitive dysfunction, denial, poor judgment, or psychiatric symptoms and thus may not be able to make an informed decision even at early stages of the disease. In early stages of the disease, patients may want to avoid the topic of advance directives, as they have difficulty confronting their declining ability to function as parents, employees, and other roles they fill in their lives. In late stage HD, communication becomes the predominant issue, as patients cannot make their wishes clearly known.

Advance directive decision-making may also be delayed by the dynamics of the family. First of all, once a patient becomes mentally incompetent or is unable to communicate his or her wishes, deciding on who should make these decisions becomes a source of controversy. Furthermore, the family not only has to deal with the shock of a newly diagnosed relative, but also may become increasingly worried about other at-risk individuals. In order to cope, families may be experiencing what medical professionals have deemed denial —a common, short-term protective mechanism for dealing with the shock of diagnosis. If end-of-life care is not discussed early enough, family members may not agree with the patient’s decisions.

Despite the obstacles in addressing advance directives at an early stage of disease, the value of deciding between options for end-of-life care early-on is an important means of ensuring autonomy for HD patients.

Elements of Advance Directives^

Advance directives have several important elements: a health care proxy, a living will, do-not-hospitalize and do-not-resuscitate orders; decisions about tube feeding; and decisions about brain donation for diagnosis and research purposes.

Healthcare Proxy^

A healthcare proxy is a person who makes decisions for the patient once the patient is deemed unable to make those decisions for himself or herself, and is usually a family member of the patient. The healthcare proxy should be an adult over 18 who is mentally, physically and emotionally equipped to make decisions. The healthcare proxy form is approved by law in all states and is a written document. It is very important that a patient’s doctor knows who is appointed health care proxy, and that a healthcare proxy is chosen earlier rather than later.

Living Will^

A living will is a set of instructions to a doctor about treatment and life-sustaining procedures. It is helpful for the patient to discuss living wills with a medical professional to stay informed about the advantages and disadvantages of all types of treatments and procedures. These instructions do not become effective until two doctors certify in writing that the patient is unable to make a healthcare decision. Lastly, the patient can change or revoke advance directive instructions anytime, as long as s/he has the mental capacity/communication abilities to do so.

Feeding Tube^

The wishes of the patient in regards to use of a feeding tube can be stipulated in the advance directive. Feeding tubes are usually used when the patient has no other way to swallow food. They may also be used to provide supplements when the patient can eat but needs to receive more nutrition through the tube. Tube feeding is common in late-stage HD treatment. The tube is made of soft plastic and is usually inserted into the stomach. It can be used to avoid problems such as aspiration, which is when food goes into the lungs instead of the stomach. Aspiration can increase the likelihood of pneumonia, which can cause serious medical complications in HD patients. The advantages of the feeding tube include: 1) ensuring that the body receives essential nutrients, 2) allowing patients to eat foods that they enjoy, 3) ameliorate weight loss, which is a serious health risk for late-stage HD. Disadvantages include: 1) medical risks associated with feeding tube insertion, such as infection or bleeding, 2) not all patients gain weight and feel full while on the feeding tube, 3) vomiting and aspiration can still occur occasionally, 4) potential re-hospitalization if the feeding tube is dislodged. In the end, it is the patient’s decision whether or not he/she would like a feeding tube if he/she is deemed capable of making healthcare decisions—but again, the decision should be discussed early and included in the advance directive if desired, as the patient may not continue to be able to choose for him/herself.

Do Not Hospitalize Order^

A “Do Not Hospitalize Order” (DNO) is one way for patients and families to influence the type of care patients and their families receive, and where the care takes place. During late-stage HD, people may prefer the warmth and comfort of a home, or they may wish to be hospitalized. There are numerous advantages and disadvantages to each choice. Hospitalization allows patients to have more advanced medical care. Physicians can more quickly diagnose and treat patients and have access to specialized equipment that might be needed to treat certain conditions. However, hospitalization is undesirable for some patients because hospital staff is less familiar with the patient and their individual needs. Patients sometimes become anxious in the unfamiliar surroundings, and may dislike the repeated diagnostic tests, such as blood pressure measurements.

Do Not Resuscitate Order^

A “Do Not Resuscitate” (DNR) order is written by the patient’s doctor in consultation with the health care proxy and other family members. This order states that cardio-pulmonary resuscitation (CPR) will be withheld when a person’s breathing or heart stops. When anyone is admitted to a hospital or nursing home, the staff is required by law to perform CPR if and when breathing or the heart stops unless there is a DNR order in effect (3). Like the “do not hospitalize” order, the DNR can be changed at anytime provided that the patient is mentally capable.

Brain Donation^

Brain donation involves donating brain tissue after death so researchers can use it to study HD and other neurodegenerative diseases. Researchers can use brain tissue to directly analyze nerve cells and brain changes due to HD in humans, which is an important step on the path towards better understanding HD and finding treatments that work.

There are several challenges that make brain donation challenging for some individuals.
First, the patient or his/her relatives must agree to donate the brain before the time of death. Second, not all institutions have the resources to pay for brain donation, as it costs between 10,000-30,000 US dollars to collect each brain.

Thinking Towards the Future^

While it may seem a bit overwhelming to face end-of-life care issues at a young age or during early stages of Huntington’s disease, it is extremely important to do so in order to ensure that patients’ true wishes are met even if patients are unable to make or communicate their decisions in the future. There is a lot of information available regarding each of these decisions, and speaking about each of them early on can potentially reduce stress during late-stage HD when family members and health care workers need to be aware of a patient’s desires. Finally, it is important to remember that the advance directive is a “living” legal document and any instructions specified in the document can be changed or revoked at the patient’s discretion at any time, as long as s/he has the mental capacity/communication abilities to do so.

Further Reading (GREAT LINKS!):^

Works Cited^

Klager J., Duckett A., et al. Huntington’s Disease, A Caring Approach to the End of Life, Care Management Journals. 9.2 (2008).

This medium-difficulty article describes challenges in end-of-life care, identified in a long-term care facility specializing in Huntington’s disease

Kretzschmar H. Brain banking: opportunities, challenges and meaning for the future. Nat Rev Neurosci. 2009 Jan;10(1):70-8. Epub 2008 Dec 3.

This easy-to-read article describes how brain banking is important for science, and the challenges that stand in the way

Sheila A. Simpson, Late Stage Care in Huntington’s disease, Brain Research Bulletin. 72.2-72.3 (2007): 179-181.

This easy-to-read article describes issues that should be addressed in late stage care for HD.

P. Bakhai, 9.19.11


Insurance and HD

Healthcare reform has been a hot topic in the United States in recent years, and many important changes are continually being made. In this article, we will take a look at some alterations that are particularly relevant to HD patients and their families. The first half of the article discusses the Genetic Information Nondiscrimination Act (GINA), and how it impacts insurance and employment for individuals who are at-risk for genetic conditions like HD, as well as those who are considering a genetic test. Next, this article covers the new Affordable Care Act, and changes to insurance policies for patients with pre-existing conditions, such as HD.

GINA (Genetic Information Nondiscrimination Act)^

In May of 2008, the updated Genetic Information Nondiscrimination Act (GINA) was signed into federal law. All of its contents came into effect by May 21, 2010.

What does GINA cover?^

GINA is meant to prohibit health insurers and employers from discriminating against anyone based on genetic information. This means that no one can be denied insurance or charged a higher premium based on genetic information, and that health insurance companies cannot request genetic information from any person or their family members. In addition, employers cannot make decisions about hiring, firing, or promotion based on genetic information.

What qualifies as genetic information?^

  • Any genetic tests of an individual, including those done in a research study. A genetic test is formally defined as “an analysis of human DNA, RNA, chromosomes, proteins, or metabolites that detects genotypes, mutations, or chromosomal changes.”
  • Results of a genetic test or record of participation in services such as genetic testing, genetic research, and genetic counseling for an individual’s family members, up to 4th degree relatives
  • Genetic tests of a fetus or embryo, including those conceived through IVF
  • Family history of any genetic diseases or disorders

What is not covered by GINA?^

GINA does not apply to life insurance, disability insurance, long-term care insurance, and employers with fewer than 15 employees.

It is also important to note that GINA is not retroactive, meaning that any decisions made before the law came into effect cannot be challenged. However, any employer or insurer who holds genetic information can no longer use it, even if the information was obtained before GINA existed.

Once someone exhibits symptoms of a genetic disease or disorder, that individual is not covered by GINA. In this case, any insurance or employment decisions made based on the existing condition are legal. For patients at this stage of disease, the Affordable Care Act of 2010 may be relevant.

Affordable Care Act ^

What is the Affordable Care Act?^

Signed in March of 2010, the Affordable Care Act introduces a wide variety of changes to health insurance policies and costs in the United States. Its various components are being implemented independently, so pay attention to when each change becomes law!

What if I have HD and don’t have insurance right now? ^

Under the Affordable Care Act, adults with existing disabilities and mental or physical illnesses cannot be denied health insurance coverage as of January 1, 2014. The same rule has been in place for children since September 23, 2010.

If you are an HD patient, one current option for coverage is the Pre-Existing Condition Insurance Plan (PCIP) in your state. Some states are choosing to operate their own PCIPs, while others are offering federally-run plans.

All legal U.S. residents who have been without insurance for at least six months may apply for PCIP coverage. This also applies to those who have been denied insurance or charged an unaffordable premium in the past due to their condition. Eligibility is not based on income. PCIP covers primary and specialty care, hospital care, and prescription drugs, including any services needed to treat or manage a pre-existing condition. Note, however, that a positive genetic test for HD cannot be considered a pre-existing condition, so individuals with a positive gene test can and should apply for regular insurance programs instead of PCIP.

Currently, because PCIP premium amounts vary from state to state, some patients may need to apply for Medicaid or other assistance programs if PCIP costs are too high. In these cases, all terms and conditions for Medicaid eligibility must be met, regardless of any pre-existing conditions. Gaining better coverage for low-income or unemployed individuals is an ongoing effort, but there has not been significant progress on this front.

What if I have HD and already have insurance?^

If you have had health insurance coverage since September 23, 2010, your insurer cannot unfairly cancel coverage, deny services, or raise premiums, even if your condition worsens and demands expensive treatments or medications. This applies even if you accidentally forgot to mention a symptom experienced or treatment received when submitting your insurance application. Note, however, that intentional omissions, untrue information, and late payments can still be used as reasons to cancel coverage or refuse services.

Lifetime dollar amount limits on essential services have also been illegal since September 23, 2010, and annual limits will be banned for many services after January 1, 2014. If financial hardship or another extenuating circumstance causes you to lose coverage, insurers must provide a 30-day warning before terminating your policy. You will be eligible to apply for PCIP 6 months after the termination.

A new Healthcare Exchange program is currently in the works, and may provide better coverage or lower premium options for patients with pre-existing conditions, such as HD. Many changes have been discussed and considered in Congress over the past few years, so staying informed about the latest developments in healthcare reform is necessary and helpful.

For Further Reading:^

The government’s official guide to the Affordable Care Act

Full text of the Genetic Non-Discrimination Act of 2008

Kaiser Family Foundation’s Guide to Health Reform (very up-to-date)

S. Liou, 8/30/2011


Family Planning

Family Planning

The decision to have a family comes with a great deal of responsibility, and many important choices. For people with Huntington’s disease (HD), one of the most pressing considerations in their decision to have children relates to the disorder. People with HD have a 50% risk of passing the disease to their offspring each time they conceive, unless they attempt an alternative method that stops HD from being inherited through the generations. Those “at risk” of HD, who have parents or relatives with the disease but do not wish to be tested to see whether they are affected, also have the potential to pass HD on to their children as they might be HD-positive.

This article outlines a number of reproductive options available to couples that know their HD status, and to those who prefer not to know. There is no easy answer, and each couple may come to a different conclusion based on their personal preferences and system of beliefs. This article provides possibilities: the solutions, however, can only be reached by the individuals themselves.

Decide whether to get tested^

The first decision a couple faces is whether or not the person at risk should get tested for HD; the test results might significantly shape the choices a couple makes in planning their family. For more information on genetic testing, click here, and to learn more about how getting tested might affect romantic relationships, click here. Getting tested is not necessary, as people who are at risk have several ways to avoid passing on HD without finding out their own status, but it might be helpful.

Not having children/Adoption^

Upon learning of their HD-positive or at risk status, some people choose to not have children. Many people that make this choice do so to avoid the risk of passing HD on to their children, expressing guilt at the thought of transmitting the disease (Decruyanaere et al., 2007). Other couples worry they won’t be able to fully raise the child before the HD-affected parent’s symptoms set in, and they don’t want the disease to compromise their parenting (Klitzman et al., 2007). On one hand, couples who don’t have children can rest easy knowing that they will never pass HD on to future generations; on the other, some may regret not having children (Decruyanaere et al., 2007).

Couples that don’t want to remain childless sometimes decide to adopt instead.  Adoption helps a needy child, and allows a couple to raise children without passing on HD. Prospective parents generally work with adoption agencies to help them through the adoption process, and to help them screen children to find the right match. The decision must be weighed carefully, as prospective parents need to consider whether HD will jeopardize their ability to raise children; some adoption agencies might refuse to let HD-positive people adopt on these grounds (Klitzman et al., 2007). For more information about adoption, click here.

Natural Conception^

Many couples choose to have children naturally. If one parent is HD-positive, then the child has a 50% chance of having HD. If one parent is at risk (and therefore has a 50% chance of having the disease), their child has a 25% of having HD – though that number increases to 50% if the at risk parent begins to show symptoms. If both parents have HD, then the child has a 75% chance of having the disease.

Parents who accept these risks and have children naturally often say that their desire to have children outweighs their fears about HD. They acknowledge that their child might inherit the disease, but express hope that a cure for HD may be found in their child’s lifetime; they also point out that even if no cure is found, their child will have many disease-free years, as HD rarely sets in before age 40 (Decruyenae et al., 2007).

Sperm or egg donation/Surrogate mother^

Couples also have the option of sperm or egg donation, depending on which partner is affected by HD. If the prospective father is HD-positive, couples might consider sperm donation, in which a donor’s sperm is inserted into the prospective mother’s uterus or vaginal canal using a syringe. For more information on sperm donation, click here. If the prospective mother is HD-positive, couples can have children through egg donation, in which another woman donates her eggs and they are fertilized with the father’s sperm through in-vitro fertilization (IVF). Alternatively, a couple could consider having a child with a surrogate mother, where the father’s sperm is inserted into a surrogate mother. However, while sperm donation is relatively inexpensive at several hundred dollars, both egg donation and surrogacy cost thousands of dollars; couples in which the prospective mother has HD generally choose other reproductive options instead.

Test Tube Babies: Preimplantation Genetic Diagnosis (PGD)^

Pre-implantation Genetic Diagnosis (PGD) screens embryos for genetic diseases, such as HD, before they are implanted in a woman’s body. This exciting new technology, developed in 1998, allows couples to prevent their children from inheriting genetic diseases that run in the family (Decruyenae et al., 2007).

To generate the embryos used in PGD, the couple must first undergo in-vitro fertilization (IVF). In IVF, a woman’s eggs and man’s sperm are combined in a laboratory. First, some of the woman’s eggs are collected. Since women usually only release one egg every month, doctors give the woman fertility medication to cause her to release many eggs at once, a process called “superovulation”. The eggs are monitored using ultrasound imaging. Once they are mature, the doctors perform a minor surgery. The woman is given local anesthetic, which numbs the area the doctor will be working on, and sedatives, which put her to sleep. Then, using ultrasound, the doctor guides a hollow needle to the ovary and removes the eggs.

The eggs are then fertilized using the man’s sperm. This is the step that earned this procedure the name “in vitro fertilization”: “in vitro” is Latin for “in glass”, referring to the fact that the fertilization is performed in test tubes or petri dishes, rather than in the body –which gave  rise to the term “test tube babies”. The sperm and egg combine to form a single-celled embryo, which grows and divides. For more information on IVF, click here.

Once the embryo has reached the 8-cell stage, PGD is performed. One of the eight cells of the embryo is removed for testing. This procedure is harmless, as the embryo is still composed of stem cells, and can easily grow to replace the lost cell. Since every cell has a complete copy of the genetic code, any one cell will suffice for genetic testing. At this point, a “genetic diagnosis” is carried out on the cell. However, geneticists can’t use the same test that is used to check adults for the HD allele, as one cell isn’t enough to test for CAG repeats directly (a process described here). Instead, scientists take blood samples from both prospective parents, and from the parents of the at-risk individual. They then look at the genes right next to the HD allele, and choose a “marker” – a unique fingerprint of DNA that differs between the chromosome with the HD allele, and those without. Since genes that are close together are almost always inherited together, the embryos with the HD allele will also have this particular marker. Therefore, an embryo that tests positive for the marker is considered “affected”; it carries the HD allele, and is expected to have HD. Embryos that do not carry the marker are “unaffected”, and are considered for implantation (Sermon et al., 2002).

The doctor will then implant between 1-4 embryos. Usually, more than one embryo is implanted, to increase the chances of a successful pregnancy. If the first implantation process fails, and there are enough unaffected embryos remaining from the egg retrieval process, the doctor can simply perform a second implantation. However, if there aren’t enough unaffected embryos remaining, the woman will have to begin the entire process again, starting from egg retrieval.

To summarize, the woman undergoes egg retrieval in which several eggs are collected. Those eggs are fertilized with the man’s sperm through IVF, and allowed to divide to the 8 cell stage. PGD is performed on one cell of each embryo, and the embryos that are HD-free are selected for implantation. This process, while complicated and expensive, virtually ensures that the children of a PGD-tested couple will be HD-free – the only risk of the child having HD would come from human error, and is extremely small.

PGD comes with a handful of medical risks. As multiple embryos are implanted, some women end up having more than one child. Some may be happy with this result, but others might have a more difficult pregnancy. Another problem – ovarian hyperstimulation syndrome – is caused by an over-reaction to the fertility medication used. The problem, which causes symptoms such as diarrhea, nausea, and dizziness, can be solved by drinking more water. Other complications, such as infections acquired during surgery, are treated with antibiotics. For a full discussion of risks, click here.

Non-disclosing PGD^

An alternative form of PGD exists for those who don’t wish to be tested. As with disclosing PGD, IVF is performed to create embryos, and doctors perform PGD to determine which are affected, and which are HD-free. The difference between disclosing and non-disclosing PGD is that the doctor never reveals the at-risk parent’s status: the parents do not find out how many embryos were affected (if any), and do not know how many embryos were implanted.

Non-disclosing PGD brings up a number of weighty issues. First, the doctor knows the status of the at-risk parent, but must keep it a secret. Even if the news is good – if none of the embryos have HD, the parents are almost certain to be HD-free – the doctor can’t reveal the parent’s status, as this would compromise secrecy for other clients; clients who were not congratulated would know their HD-positive status by default (Braude et al., 1998).

Second, if the parent is a carrier, and all embryos are affected, then a “mock transfer” is carried out; the doctor performs an implantation in which no eggs are implanted. This ensures that the person doesn’t find out his or her HD-positive status. Some countries, such as Holland, consider this an unnecessary medical risk, and therefore require the at-risk individual to be tested before undergoing PGD (Asscher and Koops, 2010).

Third, half of the couples that choose non-disclosing PGD are perfectly healthy, and therefore undergo IVF-PGD when they could simply have a natural pregnancy. Again, this factored into Holland’s decision to force couples to get tested before resorting to PGD, as half of the couples will avoid the cost and medical risks of IVF-PGD. However, the US and most other countries have no such policy, and non-disclosing PGD is accepted and performed (Asscher and Koops 2010). For a discussion of the right not to know, click here.

In short, PGD allows couples to have children that will be HD-free. The procedure, admittedly, is physically and emotionally draining, particularly because the success rate is currently around 20%; a couple may have to undergo multiple rounds of IVF-PGD for a successful pregnancy (Sermon et al., 2002). Furthermore, with a price-tag of $9,000-$18,000, this procedure might be out of reach for some couples, particularly if their health insurance companies refuse to subsidize the cost. However, many HD-positive or at-risk couples have had successful pregnancies through IVF-PGD. For an account of an HD-positive mother who had twins through IVF-PGD, and successfully lobbied her health insurance company to cover most of the expenses, please click here.

Testing the Fetus: Prenatal Diagnosis^

Another option exists for women who are already pregnant: Doctors can perform a prenatal diagnosis, in which the fetus is tested for HD. As with PGD, this procedure can take two forms: HD-positive people undergo a “disclosing” prenatal diagnosis, and people who are at-risk but do not wish to be tested can have “non-disclosing” prenatal diagnosis, in which their fetus is tested for the risk of HD and the parent’s status remains unknown.

Prenatal diagnosis can be performed through chorionic villus sampling (CVS) or amniocentesis. In both, a needle is guided by ultrasound imaging to collect a sample of cells for genetic testing. In CVS, the needle is inserted into the uterus through the vagina, and collects a few cells from the placenta, the organ that develops alongside the fetus and supplies it with oxygen and nutrients from the mother. CVS is usually performed 10-13 weeks after the mother’s last menstrual period. Amniocentesis is performed later, around 14-20 weeks into the pregnancy. In amniocentesis, a needle is inserted through the abdomen into the uterus and takes a sample of amniotic fluid – the fluid surrounding the fetus – for genetic testing. Both CVS and amniocentesis are very safe procedures, though there is a very small increase in risk of miscarriage. For more information on CVS, please click here, and to read more about amniocentesis, please click here.

Once those samples are taken, genetic tests are performed. For a disclosing prenatal diagnosis, doctors determine the number of CAG repeats the fetus has in its Huntington gene, as described here. If the fetus has 35 or fewer CAG repeats, it is considered HD-free; with 40 or more CAG repeats, it is considered HD-positive; with 36-39, the fetus has an uncertain prognosis, and may or may not develop HD in its lifetime.

If the parent is at-risk for HD, but does not wish to know their status, a non-disclosing prenatal diagnosis is performed through “exclusion testing”. In exclusion testing, the CAG repeats are not directly measured; instead, doctors look at “linked markers” to see which parent the fetus inherited its genetic material from, as previously described in the PGD section of this article. In this method, the couple must get in touch with their parents to collect small blood samples for testing. For the HD-positive parent of the “at-risk” person (the “grandparent” of the fetus), the doctors find markers for the Huntington gene. The doctors consider the fetus at risk of developing HD if either of the affected grandparent’s copies of the Huntington gene are present in the fetus; the grandparent’s HD allele, as well as the grandparent’s non-HD allele, both cause the fetus to be deemed “high-risk”. Therefore, there is a 50% chance that the fetus will have HD if it is marked as high-risk.

After a few weeks, the parents obtain their results. If the fetus is HD-free, the parents can rest easy; the child won’t suffer from the disease, and will never pass HD on. Unfortunately, some parents will receive upsetting results from the genetic test, and have a difficult choice to make.

Parents who are informed that their fetus has HD sometimes choose to keep the child, and do so for a number of reasons. Some say their desire for a child outweighs their fears about HD; others point out that the child will have many disease-free years before symptoms begin; still more express the hope that a cure for HD may be found in their child’s lifetime (Decruyenae et al., 2007). Views on abortion also play a large part in many people’s decisions; for some, their opposition to abortion outweighs their desire to prevent HD from being passed on to their children. A handful of parents don’t believe the results of a prenatal diagnosis should be grounds for abortion because they consider this the first step down a slippery slope towards a eugenic society, in which we begin choosing traits for our children (Klitzman et al., 2007).

All of these concerns are valid points, and deserve careful contemplation. However, most couples that learn that their fetus is HD-positive decide to terminate the pregnancy (Decruyenae et al., 2007). These parents often say they would feel unethical bringing an HD-positive fetus to term, as they don’t wish to subject a child to the difficulties they themselves have undergone (Klitzman et al., 2007).

The decision becomes even more difficult for parents who choose a non-disclosing prenatal diagnosis, and learn that their child is “high-risk”. While the fetus has a 50% chance of being HD-positive, there is still a 50% chance that the fetus is HD-free. For this reason, some countries, such as France, make it very difficult for a woman to have an abortion on the grounds of a non-disclosing prenatal diagnosis (Sermon et al., 2002).

This decision is difficult to make, and parents will have to weigh many personal, moral, and religious considerations; this article only scratches the surface of factors that might take a part in the choice. Some parents choose to avoid prenatal diagnosis entirely, as they don’t wish to risk the psychological and physical burden of abortion (Decruyenae et al., 2007). Ideally, a couple should discuss these issues with a genetic counselor; if possible, counseling should begin before the couple conceives, especially for non-disclosing prenatal diagnosis, as it may take longer than expected for doctors to find useful linked markers for the test.


Despite the difficulties of living with an inheritable disease, prospective parents should not feel limited by their HD-positive or at-risk status; those who wish to have children have many options, many of which prevent the passage of HD. This decision involves difficult choices, where a couple must weigh personal moral, ethical, and religious beliefs, while taking into account the opinions of family members and close friends. The end result, however, is well worth the work.


1.     “Amniocentesis : American Pregnancy Association.” Promoting Pregnancy Wellness : American Pregnancy Association. American Pregnancy Association, Apr. 2006. Web. 25 June 2011. <>.

This is an easy-to-read website with an in-depth discussion of amniocentesis, going into how the procedure is done, and any risks that might be involved.

2.     “Chorionic Villus Sampling: CVS.” Promoting Pregnancy Wellness : American Pregnancy Association. American Pregnancy Association, Apr. 2006. Web. 17 June 2011.

This is an easy-to-read website with an in-depth discussion of CVS, going into how the procedure is done, and any risks that might be involved.

3.     Asscher E, Koops BJ. The right not to know and preimplantation genetic diagnosis for Huntington’s disease. J Med Ethics. 2010 Jan;36(1):30-3

This is an easy-to-read paper on the ethics of non-disclosing PGD and non-disclosing prenatal diagnosis

4.     Braude PR, De Wert GM, Evers-Kiebooms G, Pettigrew RA, Geraedts JP. Non-disclosure preimplantation genetic diagnosis for Huntington’s disease: practical and ethical dilemmas. Prenat Diagn. 1998 Dec;18(13):1422-6. Review.

This article explores some of the ethical considerations that non-disclosing prenatal diagnosis and non-disclosing PGD bring up, and could be useful for at-risk individuals.

5.     Decruyenaere M, Evers-Kiebooms G, Boogaerts A, Philippe K, Demyttenaere K, Dom R, Vandenberghe W, Fryns JP. The complexity of reproductive decision-making in asymptomatic carriers of the Huntington mutation. Eur J Hum Genet. 2007 Apr;15(4):453-62. Epub 2007 Jan 24.

This is an easy-to-read study looking into the reproductive decision-making process of couples who know their HD-positive status.

6.     Klitzman R, Thorne D, Williamson J, Chung W, Marder K. Decision-making about reproductive choices among individuals at-risk for Huntington’s disease. J Genet Couns. 2007 Jun;16(3):347-62.

This is an easy-to-read study looking into the reproductive decision-making process of couples that are at-risk, but do now wish to be tested.

7.     Sermon K, De Rijcke M, Lissens W, De Vos A, Platteau P, Bonduelle M, Devroey P, Van Steirteghem A, Liebaers I. Preimplantation genetic diagnosis for Huntington’s disease with exclusion testing. Eur J Hum Genet. 2002 Oct;10(10):591-8.

This technical paper describes how PGD is performed.

8.     “What Are the Risks of PGD Treatment?” Guy’s and St Thomas’ Centre for Preimplantation Genetic Diagnosis. Centre for Preimplantation Genetic Diagnosis, 18 May 2009. Web. 29 June 2011. <>.

This easy-to-read website that discusses the medical risks of PGD.

M. Hedlin, 7.20.11; recorded by B. Tatum, 8/21/12


About Lifestyle and Huntington's Disease

Even when a person is at risk for developing HD there are many things he or she can do about it. Yes, everyone with the HD allele allele will eventually display symptoms of HD. However, the expression of these symptoms is subject to great variability. For example, studies of the HD population in Venezuela revealed that there is great variability in the age of onset (the age at which symptoms first appear) of HD. While the number of repeats of the CAG codon is the most important factor in determining age of onset, it is not the only factor. There may be a big difference in the age at which two individuals with the exact same repeat length-and even genetically identical twins-begin expressing symptoms of HD. Researchers found that, after controlling for repeat length, about 60% of the variance in age of onset is environmental (“variance” is a statistical measure of variability). This important finding means that genes do not completely determine the expression of HD: the environment plays an important role. The implication is that everyday practices regarding diet, exercise, and stress management can greatly influence the onset and progression of HD. While these practices are by no means “cures” or even treatments for HD, they do promote health. Also, it is important to realize that while a correlation may exist between such practices and good health, and even improvement in HD symptoms, that correlation does not mean that the practices are themselves causing the good results. Other factors may be involved. In any event, it is important to consult your medical doctor before making any drastic changes in your lifestyle.

General health promotion strategies address the mental, physical, spiritual, and social connections of who we are and how we live. Through both action and inaction people make choices about their health on a daily basis. Each of us has general health strategies that we are implementing all the time. Taking a moment to look at what your own health strategies are–giving them names, refining them, and exploring ways to improve them–is the very foundation of health. In the big picture, people who proactively address health on all fronts have a tendency to do better than people who do not. The purpose of this chapter is to provide information about life practices that promote general health, and to explore how these life practices may affect the way that individuals respond to HD. Despite the fact that people with the HD allele will eventually show symptoms, the expression of these symptoms can be greatly influenced by the lifestyle choices that those individuals make.


Diet and Neurogenesis

A novel track of research has unearthed new meaning to the old adage “you are what you eat”. Research suggests that our diet plays a role in neurogenesis, the process by which we produce new neurons. Therefore, a diet rich in “brain food” may promote neurogenesis and thereby might repair some of the damage brought on by Huntington’s disease (HD).

Neurogenesis and HD^

The old myth that a person is born with as many neurons as he would ever have has recently been overturned. Though neurogenesis is most abundant before birth, scientists have shown that adults can make new neurons throughout life. This allows our brains to age gracefully, as these new neurons work to replace the neurons that inevitably die. Neurogenesis allows us to have flexible brains throughout life, which is critical for learning new skills (Greenwood and Parasuraman, 2010). For more information on neurogenesis, click here.

In particular, neurogenesis is important in the context of HD. Neurogenesis continues to occur in HD patients and, in fact, increases as the disease progresses. This increase is thought to be the brain’s attempt to repair itself in response to the widespread neuronal death caused by the disease. However, neurogenesis does not happen fast enough to counter the damage incurred (Taupin, 2008).

It is possible that a diet that promotes neurogenesis could help counter some of the deficits experienced by HD patients. Some scientists have explored how diet can impact neurogenesis, and have found a number of nutrients and dietary regimes that may play a role.

Dietary Restriction^

One major track of research on diet and neurogenesis focused on dietary restriction (DR). DR is a strategy wherein calories are limited to about 70% of the normal diet (Levenson and Rich, 2007). This calorie reduction has been shown to lengthen lifespan; the lives of rats and mice can be extended by as much as 50% if they are put on a restricted diet at a young age, and maintain that diet throughout life. In rats and monkeys, DR helps protect against age-related diseases, like cancer, diabetes, and cardiovascular disease (Mattson et al., 2004)

Scientists think DR brings about these beneficial effects by conditioning cells to be better at protecting themselves. DR is a mild stress that puts cells on the defensive, and causes them to start expressing protective genes and stockpiling useful proteins. Therefore, cells stressed by DR are better able to cope with further stressors. For more information on DR, click here.

One stressor that occurs in many neurodegenerative conditions, like Alzheimer’s, Parkinson’s, and HD, and can be ameliorated by DR, is oxidative stress. In HD, oxidative damage occurs when injured neurons release free radicals, which go on to damage neurons around them (Mattson et al., 2004). For more information on oxidative damage, click here. Therefore, DR may help patients with neurodegenerative diseases by causing neurons to fortify themselves, which could prepare them for the stress caused by HD.

Scientists also believe that DR can help patients with neurodegenerative conditions by promoting neurogenesis. DR increases adult neurogenesis in young adult rats, and reduces age-related declines in neurogenesis in older mice (Levenson and Rich, 2007). Furthermore, DR stimulates neurogenesis in the hippocampus, a brain region important for memory. DR also causes an increase in levels of BDNF, a protein shown to help newly born neurons survive (Mattson et al., 2004). For more information on BDNF, click here. Researchers have found that DR can improve the symptoms of HD and several other neurodegenerative conditions in mice. When rats were injected with a chemical that causes brain damage, the rats kept on a restricted diet were more resistant to the chemical’s neurodegenerative effects, and showed fewer learning and memory problems (Mattson et al., 2004). When HD mice were kept on a restricted diet, they showed less striatal neuron death, it took longer for movement problems to arise, and the mice lived longer (Mattson et al, 2004). So DR may protect against neurodegenerative conditions by stimulating neurogenesis and causing neurons to fortify themselves.

DR, however, is a drastic strategy: it takes tremendous willpower to limit calories to 70% of the normal diet. Furthermore, DR is difficult to implement properly; there is a risk of starvation if the diet is unbalanced, which can have wide-ranging consequences. Luckily, similar effects to DR have been found in mice by simply increasing the amount of time between meals (Stangl and Thuret, 2009).

Some scientists have attempted to harness the beneficial effects of DR through resveratrol, a chemical found in red wine. Resveratrol mimics many of the effects of DR, and is thought to work through the same biological pathways (Greenwood and Parasuraman, 2010). For more information, click here.

So DR and resveratrol may promote neurogenesis, and in this way might protect against the brain damage found in HD.

Dangers of a High-Fat Diet^

Conversely, researchers have also studied situations where cells have too many calories, and have found that neurogenesis is impaired. Mice on a high-fat diet have lower levels of BDNF in the hippocampus, and decreased neurogenesis in a particular area of the hippocampus called the dentate gyrus (Park et al., 2010). Furthermore, when injected with a chemical that injures the brain, mice fed a high-fat diet experienced much more damage than those fed a normal diet. Diets high in fat also decrease the learning and cognitive capabilities of rats (Greenwood and Prasuraman, 2010). Thus, experiments on rodents consistently show that a high-fat diet is unhealthy for the brain.

Vitamins, Nutrients, and Foods that promote Neurogenesis^

Another line of research on diet and neurogenesis has investigated the effect of dietary nutrients on the birth of new neurons. Several antioxidants, such as flavonoids, vitamin E, and curcumin, increase neurogenesis in rodent brains. Antioxidants are chemicals that prevent damage from free radicals, and thus might promote neurogenesis by protecting new neurons, among other things (Gómez-Pinilla, 2008). Flavonoids, found in cocoa and blueberries, are chemicals that increase neurogenesis in the hippocampus of stressed rats, possibly by increasing levels of BDNF (Stangl and Thuret, 2009), and/or by improving blood flow to the brain, which can increase hippocampal neurogenesis (Spencer, 2009). Vitamin E, abundant in vegetable oils, nuts, and green leafy vegetables, aids neurological performance in aging mice (Gómez-Pinilla, 2008). Curcumin, found in yellow curry spice, may increase neurogenesis in the hippocampus of rodents by activating certain cell signaling pathways known to increase neurogenesis and decrease stress responses (Stangl and Thuret, 2009). For more information on curcumin, click here.

Another antioxidant, found in green tea, goes one step further than the others. The chemical (-)-epigallocatechin-3-gallate (called EGCG) promotes neurogenesis in the hippocampus (Yoo et al., 2010), and has been shown to reduce the damage from oxidative stress in other neurodegenerative diseases (Ehrnhoefer et al., 2006). When flies with a form of HD were treated with EGCG, their control over their movements improved (Ehrnhoefer et al., 2006). EGCG might also directly fight the damage of HD, as it has been shown to slow the rate at which the mutant form of the huntingtin protein forms the plaques that are thought to hurt the brain (Ehrnhoefer et al., 2006).

In addition to antioxidants, other nutrients have also been shown to play a role in neurogenesis. Omega-3 fatty acids, present in fish and flaxseed, might also promote neurogenesis, and have been shown to decrease cognitive decline seen with aging and neurodegenerative diseases such as Alzheimer’s (Yurko-Mauro et al, 2010). For more information, click here. Vitamins might stimulate the birth of new neurons since, in some cases, vitamin deficiency can inhibit neurogenesis. For example, deficits in zinc inhibit neurogenesis in the hippocampus of rodents. Zinc, a vitamin essential for normal brain development, promotes the survival and proliferation of neural stem cells, which are the main cell type capable of generating neurons (Adamo and Oteiza, 2010). Therefore, zinc deficiency inhibits neurogenesis in the hippocampus of rodents. Similarly, a deficiency of retinoic acid, a metabolite of vitamin A found in animal foods such as milk, inhibits hippocampal neurogenesis (Stangl and Thuret, 2009).

Altogether, research on diet and neurogenesis is not conclusive. It is difficult to study nutrients effectively: studying a nutrient in isolation ignores many of the complex interactions the nutrient may have in the body. However, there are a few relatively consistent messages that emerge. A vitamin-rich, low-fat diet aids neurogenesis in experiments with rodents, and a low-calorie diet mitigates the effects of neurogenerative disease in mice. As for humans, this diet has not been shown to directly help neurogenesis or ameliorate the problems of HD (Huntington Study group, 2008; Block et al., 2011), but healthy diets have a vast number of other physical and mental benefits: longer life, elevated mood, and higher energy levels, to name a few. In conclusion, eating healthy might promote neurogenesis – but even if it does not, a healthy diet certainly will not hurt.

For Further Reading^

Adamo AM, Oteiza PI. Zinc deficiency and neurodevelopment: the case of neurons. Biofactors. 2010 Mar-Apr; 36 (2) :117-24

A technical paper that discusses the impact of zinc deficiency on the brain

Block RC, Dorsey ER, Beck CA, Brenna JT, Shoulson I. Altered cholesterol and fatty acid metabolism in Huntington disease. J Clin Lipidol. 2010 Jan-Feb;4(1):17-23. Review

A technical paper that discusses Omega-3 fatty acids and their effects on HD.

Curtis MA, Penney EB, Pearson AG, van Roon-Mom WM, Butterworth NJ, Dragunow M, Connor B, Faull RL. Increased cell proliferation and neurogenesis in the adult human Huntington’s disease brain. Proc Natl Acad Sci U S A. 2003 Jul 22; 100 (15) :9023-7.

A technical paper that discusses neurogenesis in an HD brain

Ehrnhoefer DE, Duennwald M, Markovic P, Wacker JL, Engemann S, Roark M, Legleiter J, Marsh JL, Thompson LM, Lindquist S, Muchowski PJ, Wanker EE. Green tea (-)-epigallocatechin-gallate modulates early events in huntingtin misfolding and reduces toxicity in Huntington’s disease models. Hum Mol Genet. 2006 Sep 15;15(18):2743-51. Epub 2006 Aug 7.

A technical paper that describes how EGCG, an antioxidant found in green tea, may change the way that the mutant huntingtin protein forms harmful plaques

Greenwood PM, Parasuraman R. Neuronal and cognitive plasticity: a neurocognitive framework for ameliorating cognitive aging. Front Aging Neurosci. 2010 Nov 29; 2:150.

A technical paper that discusses strategies to counter the neuron damage that accompanies aging, such as education, exercise, dietary restriction, and a low-fat diet, and goes into research that has been performed on rodents.

Gómez-Pinilla, F. Brain foods: the effects of nutrients on brain function. Nature Reviews Neuroscience. 2008 Jul. Review; 9:568-578.

A technical paper that discusses how various nutrients affect brain function.

Huntington Study Group TREND-HD Investigators. Randomized controlled trial of ethyl-eicosapentaenoic acid in Huntington disease: the TREND-HD study. Arch Neurol. 2008 Dec;65(12):1582-9.

Levenson CW, Rich NJ. Eat less, live longer? New insights into the role of caloric restriction in the brain. Nutr Rev. 2007 Sep; 65 (9) :412-5.

A paper that discusses the impact of caloric restriction on the brain in rodents

Park HR, Park M, Choi J, Park KY, Chung HY, Lee J. A high-fat diet impairs neurogenesis: involvement of lipid peroxidation and brain-derived neurotrophic factor. Neurosci Lett. 2010 Oct 4; 482 (3) :235-9.

A technical paper that discusses the impact of a high-fat diet on rodents

Mattson MP, Duan W, Wan R, Guo Z. Prophylactic activation of neuroprotective stress response pathways by dietary and behavioral manipulations. NeuroRx. 2004 Jan; 1 (1) :111-6.

A technical paper that discusses dietary restriction and its effect on the brain in rodents

Spencer JP. Beyond antioxidants: the cellular and molecular interactions of flavonoids and how these underpin their actions on the brain. Proc Nutr Soc. 2010 May; 69 (2) :244-60.

A technical paper that discusses the impact of flavonoids on the brain

Stangl D, Thuret S. Impact of diet on adult hippocampal neurogenesis. Genes Nutr. 2009 Dec; 4 (4) :271-82.

A technical paper that discusses the science behind various dietary strategies and nutrients that have an impact on neurogenesis in the adult hippocampus

Taupin P. Adult neurogenesis, neuroinflammation and therapeutic potential of adult neural stem cells. Int J Med Sci. 2008 Jun 5; 5 (3) :127-32.

A technical paper that discusses neurogenesis and neural stem cells

Yurko-Mauro K, McCarthy D, Rom D, Nelson EB, Ryan AS, Blackwell A, Salem N Jr, Stedman M; MIDAS Investigators. Beneficial effects of docosahexaenoic acid on cognition in age-related cognitive decline. Alzheimers Dement. 2010 Nov;6(6):456-64.

A technical paper that discusses how Omega-3 fatty acids may aid patients with neurodegenerative conditions

Yoo KY, Choi JH, Hwang IK, Lee CH, Lee SO, Han SM, Shin HC, Kang IJ, Won MH. (-)-Epigallocatechin-3-gallate increases cell proliferation and neuroblasts in the subgranular zone of the dentate gyrus in adult mice. Phytother Res. 2010 Jul;24(7):1065-70.

A technical paper that discusses how EGCG enhances neurogenesis

M. Hedlin 6/17/2011


Genetic Testing






Individuals at risk for Huntington’s disease (HD) have the option of undergoing genetic testing, which detects the presence or absence of the genetic sequence that causes HD. The decision of whether or not to undergo genetic testing is intensely personal, with many factors to consider. This chapter will provide scientific background information regarding genetic testing for Huntington’s disease.


Sleep and HD





Humans spend an extraordinary amount of their lives asleep. If you sleep eight hours every night, you will have spent one third of your entire life sleeping. But like coffee or cell phone reception, sleep is one of the most basic aspects of everyday life that you probably take for granted—when you are well-rested, you probably do not think about sleep much, but after you have pulled an all-nighter (or two), you are likely to have a keen perception of your body’s intrinsic drive to go to sleep. Although the necessity of sleep is intimately known, the scientific understanding of sleep is still very much incomplete. Scientists know that sleep is common to a wide range of organisms from the very complex, like humans, to the very simple, like worms. The shared need for sleep across distant branches of the evolutionary tree suggests that sleep serves some basic purpose.  However, scientists still have yet to answer many fundamental questions about sleep: Why do organisms need to sleep? What are the molecular and cellular mechanisms that underlie sleep? What are the genes that contribute to sleep disorders?

The importance of sleep^

Experiments in animal models have suggested that sleep is necessary for the survival of a great variety of different organisms. Multiple studies have shown that rats deprived of REM sleep (see next section) die within four to six weeks, while those completely deprived of sleep only survive two to three weeks. Sleep deprivation had a marked physical effect on these rats. The animals that were not allowed to sleep exhibited increased weight loss, decreased body temperature, impaired immune systems, progressive hair discoloration, and the appearance of skin lesions. But even with these obvious signs of deterioration, scientists still were not able to pinpoint the exact cause of death in these sleep-deprived rats. Although scientists could correlate the rapid deterioration of these animals to their total sleep deprivation, they could not identify a distinct chemical or physiological abnormality that ultimately doomed these rats.

Despite the dramatic effects of sleep deprivation in rats, similar physiological symptoms under laboratory conditions have not been observed in humans, as equivalent tests cannot be run on human subjects. Regardless, sleep loss does have recognizable and measurable effects on human cognitive function, motor performance, and mood. These negative effects can be dangerous, especially when sleep deprived individuals are engaging in attention-dependent activities such as driving, medical care and similar tasks that require critical thinking and reasoning. Sleep deprivation also impairs higher brain functions, including memory formation, verbal fluency, and creativity.  The effects of sleep deprivation can be powerfully seen in fatigue-related car accidents. For example, truck drivers who have been on the road for thirteen hours straight are fifteen times more likely to have a fatal car crash in the thirteenth hour than the first hour. In fact, many researchers have suggested that the effects of driving while sleepy can be comparable to driving when drunk. Not getting enough sleep on a consistent basis can result in the buildup of a sleep “debt” that will negatively impact attention, performance, and health.

What happens during sleep^

There is a common conception that sleep is for rest, a period during which the mind and body can rejuvenate after a hard day’s work. This assumption is not unfounded—during sleep, humans are less responsive and less mobile, not dissimilar to other states of unconsciousness such as coma (but unlike comas, sleep is rapidly reversible). However, sleep is a time of significant brain activity that can be observed using a machine known as an electroencephalogram (EEG). By hooking up many different electrodes to the scalp of a patient, researchers can measure the electrical activity that takes place in the brain during sleep. Sleep is also measured by observing eye movements, which closely correlate to the type of brain waves observed in the EEG.

The two main states of sleep have been defined as non-rapid eye movement (NREM) and rapid eye movement (REM). During NREM sleep, neuronal activity in many parts of the brain is decreased, and the waves that appear on the EEG are characteristically slower than waking states. In addition, this sleep stage is accompanied by noticeable physiological changes, including the increased secretion of growth and sex hormones and decreased motor activity, heart rate, metabolic rate, breathing rate, blood pressure and intestinal mobility. Conversely, scientists have found that during REM sleep, brain waves are similar to those observed when humans are awake. This raises the interesting question: if neuronal activity is so similar in periods of both REM sleep and wakefulness, what accounts for the drastic differences between these two states? It has been suggested that a small number of neurons are responsible for differentiating between REM sleep and waking. REM sleep is characterized by pupil constriction and rapid movement of the eyes. Accompanying physiological responses include irregular heart rate, breathing and blood pressure. In addition, REM sleep is also when human dreams occur, which have been described as intense bursts of activity in certain populations of neurons. Throughout the night, the brain will alternate between periods of REM and NREM sleep every 90 minutes, repeating this cycle five to six times every night. Although both REM and NREM periods will occur during this 90 minute time window, the proportion of REM to NREM sleep increases during the night. NREM sleep dominates just after falling asleep, while periods of REM sleep dominate in the later sleep cycles.

Despite the well-characterized neurological and physiological changes that occur during sleep, scientists are still in disagreement over the actual purpose of both NREM and REM sleep in humans. Current theories include: reducing the energy consumption of the brain, consolidating memory, promoting neural plasticity (for more information on neural plasticity, click here), and increasing the body’s synthesis of important cellular building blocks such as proteins. Even though there have been many experiments showing that sleep is correlated with these various functions, scientists have found it very difficult to develop a unified theory of why we sleep. Part of this can be attributed to weaknesses in the empirical evidence—even if certain effects are statistically significant, they are not particularly notable. For example, although research has shown that exercise can improve sleep, this is only by about 10 minutes per night.  In addition, sleep research is conducted with a variety of different methods in a variety of organisms, further confounding efforts to build a unified theory of sleep. After all, the chemistry, physiology and function of sleep could very well differ significantly between similar organisms.

Sleep and circadian rhythm ^

You probably know from experience that your body responds differently depending on the time of the day. For example, you likely find it much easier to fall asleep at night than in the middle of the day. This is because darkness activates your body’s production of melatonin, a hormone that promotes sleep. Indeed, the entire human body runs on a 24-hour cycle of wakefulness and sleep. This so-called circadian rhythm (circa-, “approximately,” –diem, “day”) is driven by pacemaker cells in the hypothalamus, the part of your brain that controls a range of vital functions, including hunger, thirst, blood pressure and body temperature. Your circadian rhythm not only controls when you are alert and when you are tired, but it also coordinates your body’s countless chemical reactions. For example, during the day, when your blood sugar levels are likely to be high from eating, your body activates the chemical reactions that break down sugar into stored energy. Conversely, during the night, when your blood sugar is likely to be low, the specific processes that create sugar from stored energy are activated. The effects of the circadian pacemaker can also be seen at a whole-organism level. Human alertness and performance is highest during the day and lowest in the hours before daylight (3:00 – 6:00am), correlating with the time that humans are likely to be awake and asleep. Additionally, immediately after waking, you have probably experienced a good period of time when you were groggy and not alert. This span of time is known as sleep inertia and can last for hours after you get up. In opposition to this sleep inertia, the circadian clock sends out wake-promoting signals throughout the day, which counteracts the propensity to go back to sleep. The opposite process happens at night, with sleep-inducing signals eventually overpowering the wake-promoting ones, resulting in sleep. This natural cycle of sleep/wake signals, driven by the circadian rhythm, explains why humans tend to sleep more efficiently at night and less efficiently during the day.

It is becoming clearer that when you sleep may be just as important as how much you sleep. Deviating from your body’s circadian rhythm can lead to neurological and physical problems. Research has shown that shift workers with jobs that require them to be awake at night (e.g. police officers, fireman and health care providers) are more likely to suffer from diminished performance, sleep issues, and stress-related disorders than those who work during the day. The latter two problems can lead to more-serious conditions such as high blood pressure, stroke and heart disease. Indeed, a report by the International Agency for Research on Cancer has concluded that shift work puts individuals at a higher risk for cancer, which may be a consequence of the cellular effects of circadian rhythm disruption.


Sleep disruption and Huntington’s disease ^

Given HD’s devastating effects on many different regions of the brain, it is perhaps unsurprising that the disease would have an effect on sleep. Although the striatum, the part of the brain most visibly affected by the disease, is not currently thought to play a large role in sleep regulation, Huntington’s disease does affect several regions that have been directly implicated in controlling sleep.  For example, patients with HD have been shown to have significant atrophy of neurons in the hypothalamus, a region of the brain intimately involved in regulating metabolism and sleep/wake cycles. It is also possible that the sleep disturbances of patients with HD are secondary effects of other disease symptoms, such as depression and anxiety.

One survey on HD and sleep performed in Britain found that 87.8% of respondents suffered from sleep problems, including restless limb movements, jerky movements, waking during the nighttime, early waking, and sleepiness during the day. These harmful symptoms have been correlated with many measurable sleep abnormalities. In a study performed by an international group of scientists, individuals with HD underwent nighttime sleep monitoring and daytime wakefulness examinations. These tests used a variety of instruments to measure sleep cycle progression, eye movements, brain activity and other physical indicators of sleep. When compared to the control group, individuals with HD spent more time in the light sleep stages (stages 1-2), experienced more periodic leg movements, and generally had lower sleep efficiency, the number of minutes spent in sleep divided by the number of minutes spent in bed. In addition, individuals with HD have been shown to generally spend less time in REM sleep. Studies have shown that the long-term deprivation of REM sleep results in symptoms similar to those seen in acute sleep deprivation—impaired cognition, unstable moods and hormonal imbalances. These effects on REM sleep have been observed in individuals that were pre-symptomatic or otherwise had very mild symptoms, suggesting that problems with REM sleep are an early indicator for HD. It is noteworthy that other neurodegenerative diseases, such as Parkinson’s disease and Alzheimer’s, show similar sleep disturbances, suggesting that these illnesses may have similar effects on the neural networks that regulate sleep.

Because of the many detrimental effects of sleep deprivation on human health, scientists believe that the sleep disturbances associated with HD can exacerbate the disease. Indeed, many of the symptoms of sleep disorders are the same as the symptoms of Huntington’s disease, including the loss of motor control, memory problems, mood changes, and impaired cognitive function. Thus, disturbed sleep may be one of the mechanisms through which the behavioral, cognitive, and motor problems associated with HD develop. It is even possible that sleep deprivation is primarily responsible for some of the symptoms of HD, a hypothesis which remains to be tested. This raises the interesting possibility that treating sleep problems can improve the lives of those with HD. Research in R6/2 mice, a transgenic mouse model for HD, has shown that regulating the sleep of affected mice significantly improves their cognitive abilities. In these studies, affected mice were given a sedative to help them fall asleep during the day, and then a wake-promoting drug to help these mice stay awake at night (normally, mice are asleep during the day and awake at night). Compared to the untreated mice, the R6/2 mice that had their sleep/wake cycles regulated by drugs showed improved performance in a series of cognitive tasks. The authors hypothesized that these beneficial effects could be due to restoration of the mice’s circadian rhythms, and that sleep therapy could one day be used to slow the progression of neurodegenerative diseases such as HD.  Another important benefit of sleep therapy could be for the caretakers of those with Huntington’s disease. Several studies have found that difficulty dealing with nocturnal sleep problems is one of the most common reasons that caretakers choose to institutionalize patients with neurodegenerative disease.

Although these mice studies are promising, the effects of sleep regulation on humans with HD have yet to be studied. However, the evidence so far indicates that sleep therapy might not only improve the symptoms of HD, but may even affect the progression of the disease. And the fact remains that we could all probably use some more sleep!


Arnul, I. et al. (2008). Rapid eye movement sleep disturbances in Huntington disease. Archives of Neurology 65(4): 482-488.
This article presents the results of a study examining REM sleep problems in patients with HD. The introduction and comment section are quite informative and very readable.

Goodman, A. & Barker, R.A. (2010). How vital is sleep in Huntington’s disease? Journal of Neurology 257(6): 882-897.
This eminently-readable article provides an excellent review of the evidence relating disturbed sleep with Huntington’s disease.

Pallier, P. & Morton, J. (2009). Management of sleep/wake cycles improves cognitive function in a transgenic mouse model of Huntington’s disease. Brain Research 1279: 90-98.
This primary source presents the results of experiments assessing the effects of drug-induced sleep therapy on mice model of HD. The introduction and conclusion are quite interesting and generally quite understandable.

Rechtschaffen, A. (1998) Current perspectives on the function of sleep. Perspectives in Biology and Medicine 41(3): 359-391.
This article offers a comprehensive review on the function of sleep. Although the writing is slightly technical, it is still quite useful and comprehensible.

Reddy, A. & O’Neill, J. (2009). Healthy clocks, healthy body, healthy mind. Trends in Cell Biology 20(1): 36-44.
This review talks about the importance of circadian rhythms. The article is quite technical.

Siegal, J. (2005). Clues to the functions of mammalian sleep. Nature 437: 1264-1271.
This review article presents some of the current theories and analyzes some of the existing evidence regarding the importance of sleep in mammals. The writing is technical, but the main points are relatively accessible.

Zisapel, N. (2007). Sleep and sleep disturbances: biological basis and clinical implications. Cellular and Molecular Life Sciences 64: 1174-1186.
This very technical article gives a review of the many different problems associated with sleep disturbances.

Y.Lu 11/12/2010; recorded by B. Tatum 8/21/12


Red Wine



People have been consuming red wine for thousands of years. Although most people drink wine because of its pleasurable sensory effects, recent studies suggest that drinking red wine may confer several health benefits. Many researchers believe that these health benefits come from a compound in red wine called resveratrol, which has been shown to exhibit neuroprotective effects in several experimental studies in test tubes as well as in various organisms including yeast, worms, and mice. A few studies also provide insight into how resveratrol may affect mice with neurodegenerative disorders and more specifically mice with the mutant huntingtin protein.

Preliminary research has suggested that resveratrol may help protect against common HD complications such as inflammation, oxidative stress, and possibly huntingtin protein aggregation. (For more information on inflammation, click here.) Further studies of resveratrol in the context of neurodegeneration and Huntington’s disease (HD) are required to understand the role of resveratrol and to assess its efficacy as a therapeutic agent. This chapter gives an overview of our current understanding of how resveratrol may combat disease, as well as how these mechanisms may have potential for HD treatment.

Resveratrol in Red Wine^

Scientists became interested in exploring the health benefits of resveratrol when its presence was first reported in red wine, leading to the possibility that it could explain a health phenomenon known as the “French Paradox.” Despite the fact that the French diet is high in saturated fats, the rate of heart disease is lower than that observed in other industrialized countries. This paradox led to the idea that regular consumption of red wine (and thus a higher consumption of resveratrol) may provide additional protection from cardiovascular disease.  Recent studies have indicated that resveratrol is not the sole agent responsible for the cardioprotective effects associated with red wine consumption, and that other highly potent red wine constituents may have even greater effects.

Why not white wine or wine in general? The skins and seeds of grapes are used in the production of red wine, but not in the production of white wine. Because resveratrol is most highly concentrated in grape skins, the concentration of resveratrol is significantly higher in red wine than in white wine.

Resveratrol is one member of a class of compounds known as phytoalexins; “phyto” meaning “plant” and “alexin” meaning “to ward off or protect.” Phytoalexins are produced by some plants to respond to stressors such as injury, fungal infection, or ultraviolet radiation. Remarkably, resveratrol may be able to protect humans as well as plants.  Studies suggest that a high resveratrol intake is associated with reduced incidence of heart disease, cancer, and age-related diseases such as Alzheimer’s disease.  HD may also be a part of this list, but additional research is needed to test this notion.

Alcohol: The Fine Line Between Moderation and Excess^

Alcohol itself (better known in chemistry as ethanol) is toxic to the human body and has no redeeming qualities from a health perspective. After alcohol is consumed, a person’s blood alcohol level rises and the body begins to “detoxify” the alcohol. The first step in this process is the conversion of alcohol to another compound called acetaldehyde. Acetaldehyde stays in the body for several hours, producing a variety of undesirable toxic effects. Acetaldehyde binds readily to the walls of red blood cells. By attaching itself to the red blood cells, acetaldehyde reduces the oxygen supply to most of the cells of the body, including the brain. Acetaldehyde also combines with hemoglobin in the red blood cells and further reduces its ability to carry oxygen, which eventually leads to hypoxia (oxygen starvation at the cellular level).

Additionally, acetaldehyde interferes with the process of microtubule formation. Microtubules are essential to the brain because they provide structural support for nerve cells and their dendrites and they also transport chemicals manufactured in the nerve cells to the dendrites. Without microtubules, dendrites weaken and die. Deficiencies in various vitamins are also induced by acetaldehyde. Although individuals vary in vulnerability to acetaldehyde, it is clear that acetaldehyde is a dangerous and toxic chemical. In addition to the complications already mentioned, alcohol can also do significant damage to the liver and central nervous system. Thus, one must exercise caution when dealing with a powerful substance like alcohol and weighing its potential benefits and costs.

Roles of Resveratrol^

Antioxidant Capabilities^

Oxidative stress (also known as oxidative damage) is believed to play a major role in the damage of nerve cells in HD. (For more information on oxidative stress, click here.) Studies indicate that resveratrol is an excellent antioxidant, which means that it is very good at combating oxidative stress. What makes resveratrol such a good antioxidant? Researchers believe that it works by inhibiting monoamine oxidase (MAO), an enzyme primarily found in the liver and nervous system that generates free radicals. Free radicals are dangerous because they are highly reactive. They tend to react with important structures in cells and accelerate cell injury. By reducing levels of MAO, resveratrol decreases the number of free radicals that degrade nerve cells. Decreasing the level of free radicals may slow the progression of neurodegenerative diseases such as HD.

In scientific studies, injecting resveratrol into rats led to decreased levels of certain free radicals in the brain. Additionally, the activities of several antioxidant enzymes increased. Not only can resveratrol help to prevent free radicals from forming, but it can also decrease the toxicity of free radicals by inhibiting a process called lipid peroxidation. Lipid peroxidation is the process whereby free radicals take away electrons from the lipids that make up our cell membranes and thereby cause damage to the cell. (For more information on lipid peroxidation, click here.) Rat studies indicate that resveratrol significantly inhibits lipid peroxidation in cells.

While resveratrol has been shown to be a powerful antioxidant in vitro and in rats, its role as an antioxidant has yet to be tested and confirmed in humans.  Because circulating and intracellular levels of resveratrol in humans may be much lower than in vitro models, its true effects on the human body are controversial.

Anti-inflammatory Capabilities^

Long-term, or chronic inflammation in the brain is believed to play a significant role in neurodegeneration in HD. Studies indicate that resveratrol acts as an anti-inflammatory agent mainly by inhibiting the action of two key enzymes: cyclooxygenase and lipoxygenase. These enzymes lead to the production of leukotrienes and prostanoids, which are chemicals that significantly contribute to the inflammatory process. Resveratrol inhibits cyclooxygenase and lipoxygenase and their production of inflammatory substances, causing inflammation to decrease.

Resveratrol may also inhibit pro-inflammatory transcription factors, which increase inflammation. Transcription factors are proteins that bind to DNA and regulate gene expression by promoting transcription. Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) and activator protein-1 (AP-1) are examples of pro-inflammatory transcription factors.  NF-kB is a transcription factor for genes that helps cells to survive, bind to a surface, specialize and grow.  It is also involved in cell inflammation.  AP-1, or activator protein-1, is also a transcription factor involved in cell proliferation and survival. Research has shown that most anti-inflammatory agents suppress NF-kB activation.  Studies have indicated that resveratrol may inhibit NF-kB and AP-1 pathways, thus preventing inflammationResveratrol has been shown to decrease levels NF-kB directly and indirectly via inhibition of associated MAP kinases, which is discussed in the “MAP kinase” section of this article.

It is still unclear how resveratrol decreases inflammation. Some studies have shown that these anti-inflammatory effects may be partially due to resveratrol’s antioxidant capabilities, while others have shown that resveratrol’s anti-oxidant and anti-inflammatory capabilities are independent of one another. Further research is necessary to arrive at a scientific consensus.

Resveratrol has been shown to have neuroprotective effects in neurons, in rat brains and in cell culture. This suggests that the anti-inflammatory capabilities of resveratrol could potentially be beneficial in HD treatment. However, this hypothesis remains to be tested.

How Resveratrol Works^

Resveratrol has a very simple chemical structure, which enables it to play a role in a wide range of biological processes. As a result, resveratrol is able to act upon many different systems within the body. The following sections discuss some potential mechanisms through which resveratrol may exert its effects.   Please note that the mechanisms outlined in the sections “Heme oxygenase,” “MAP Kinase,” “Sirtuins,” and “Prevention of Neurodegeneration,” are interdependent and influence one another in ways that are not yet understood by the scientific community.

Heme oxygenase^

Similar to resveratrol, an enzyme called heme oxygenase (HO) also decreases oxidative stress and inflammation. Because of this similarity, researchers hypothesized that resveratrol might exert its function via a mechanism involving HO. This hypothesis was supported by a study that found that when resveratrol was administered to rats, the amount of HO in the rats’ neurons increased. The effect was dose-dependent, meaning that levels of HO increased as more resveratrol was administered. The connection between resveratrol and HO is important because HO is thought to have neuroprotective effects. In addition to being a powerful antioxidant, HO also produces several byproducts that may assist in cell survival.

HO is involved in regulating cellular uptake and storage of iron. Iron levels must be tightly regulated because adequate amounts of iron are essential for many cellular functions, but excessive amounts of iron can lead to the formation of reactive oxygen species (ROS). A ROS is a highly volatile compound, which is likely to damage cells. When resveratrol increases the amount of HO, higher levels of HO may in turn affect the level of iron in the cells. Thus, one way resveratrol may exert its neuroprotective effects is by stimulating HO to balance out iron levels and protect from iron-mediated toxicity.

Although the connection between resveratrol and HO is quite intriguing, further research is needed to determine the exact details of how they work together to protect nerve cells.

MAP kinase^

Numerous studies have demonstrated that resveratrol interacts with certain mitogen-activated protein (MAP) kinase family members. MAP kinases are proteins that respond to stimuli and regulate important cellular functions including gene expression cell survival and differentiation.

Earlier studies of MAP kinases indicated that resveratrol activated all three subfamilies of the enzymes, some of which have been linked to changes in brain cells changes that form the basis of memory and learning processes.  However, the relationship between resveratrol and memory and learning processes has not been tested since the preliminary studies were published.

More recent studies have investigated how the effects of resveratrol on MAP kinases influence the expression of inflammatory mediators NF-kB and AP-1. See the “Anti-inflammatory Capabilities” section in the article to learn more about NF-kB and AP-1. In short, resveratrol inhibits NF-kB and AP-1 by acting on MAP kinases. MAP kinases reduce inflammation in part by encouraging cell death.   Studies have also suggested that the inhibition of NF-kB combats beta-amyloid plaques in neurons, helping neurons survive. See the section on “Resveratrol and the Prevention of Neurodegeneration.”

The MAP kinase subfamilies are most likely related to a wide range of other processes, some of which are related HD.  It is possible that some MAP kinases regulate heme oxidase, helping to combat oxidative stress and reduce chronic oxidative damage. (See “Heme Oxidase”)

Modulation of MAP kinases by resveratrol may inhibit or activate various pathways which in turn could reduce inflammation, promote cell death when need be, and protect against buildup of toxic protein fragments.  However, such potential effects of resveratrol on MAP kinase related pathways and the potential relevance to HD still must be investigated.


Studies in yeast and fruit flies have demonstrated that resveratrol activates a group of enzymes called sirtuins, which promote longevity in a variety of organisms. Sirtuins are important for many cellular processes including gene silencing, regulation of the cell cycle, fatty acid metabolism, apoptosis and longevity. Research has also shown that resveratrol activates an enzyme called SIRT1, the human analog of the Sir2 protein, which is found in yeast. The function of SIRT1 in humans is similar to that of Sir2 in yeast; it mediates the cell cycle, protects the cell during stress, regulates transcription, prevents the destruction of axons, and is involved in extending the life span of cells. In mice, increased production of the SIRT1 gene shows both a protective and pro-aging role in neurons. Furthermore, researchers have demonstrated that both resveratrol and direct expression of the SIRT1 gene slow neurodegeneration and cognitive decline in mouse models of Alzheimer’s disease (AD).

The majority of research supports the hypothesis that resveratrol, by stimulating the activity of sirtuins, mimics the effects of calorie restriction. (For more information on dietary restriction, click here.)  Calorie restriction has extended the life span in rodents and primates through a variety of mechanisms, one of which includes increasing levels of SIRT1.  It has even been shown to slow disease progression and increase survival in huntingtin mutant mice.  Both calorie restriction and resveratrol can decrease chronic oxidative damage, inhibit inflammatory pathways, and increase energy production in the cell. While a few studies suggest that sirtuins act independently of pathways mediated by calorie restriction, these studies do not propose an alternative mechanism for sirtuin action. Regardless of the relationship between resveratrol and calorie restriction, activation of SIRT1 proteins has had positive effects on a variety of organisms including mouse models for HD and AD.  This suggests that resveratrol itself may have the potential to delay the onset and progression of HD symptoms.

Resveratrol and the Prevention of Neurodegeneration^

Resveratrol has demonstrated neuroprotective effects through its anti-oxidant and anti-inflammatory capabilities, as well as its influence on sirtuins. Expanding upon these claims, numerous epidemiological studies (studies related to epidemiology) have determined that moderate red wine consumption is correlated with a lower incidence of dementia and a reduction in Alzheimer’s disease. (For a comparison of Alzheimer’s and HD, click here.) Nevertheless, it should be noted that the notion that red wine intake lowers AD risk is controversial. Based upon controlled studies, a dose of resveratrol much higher than the amount in red wine is needed for any positive effects. The correlation between reduced risk of dementia and moderate red wine consumption does not mean that red wine consumption or resveratrol are responsible for the reduced risk. Studies are ongoing to prove if correlation will translate to causation in this case.

Evidence suggests the possibility that resveratrol can prevent neurodegeneration in AD via protection against beta-amyloid plaquesBeta-amyloid (Aβ) plaques are an accumulation of small fibers called beta-amyloid fibrils and are present in the brains of people suffering from Alzheimer’s disease (AD). (For more on beta-amyloid plaques, click here.) These plaques are thought to greatly contribute to the neurodegenerative process of AD.  Over the past decade, there has been compelling evidence that resveratrol has the ability to protect against the neurotoxic effects of amyloid-related proteins.

In one study, researchers treated mice injected with the AD gene with resveratrol, which reduced the number of Aβ plaques.  Another study found that moderate consumption of red wine lowered Aβ levels and reduced its neurotoxic effect, implying that red wine intake may have a beneficial effect against AD pathology by promoting mechanisms that work against the accumulation of beta-amyloid plaques. Additional studies in mice and in cell cultures have supported these findings.

Because of the parallels between huntingtin protein aggregates and beta-amyloid fibrils, these results are promising developments in the search for treatments for neurodegenerative disorders like HD.  It is possible that resveratrol may also have the ability to decrease huntingtin protein aggregates. However, this hypothesis remains to be tested and other substances that have decreased beta-amyloid fibrils have had no effect on huntingtin protein aggregates.

Future studies aimed at elucidating a more detailed understanding of the various cellular mechanisms involved in the neuroprotective effects of resveratrol have the potential to open new avenues for the treatment of neurodegenerative diseases such as HD.  It is necessary to further study resveratrol in animals and most importantly, humans, before it can be proven as a safe, effective treatment for HD.

Therapeutic Potential of Resveratrol^

There are two measures that are used to determine the effectiveness of a drug: pharmacokinetics, how the body processes a drug, and bioavailability, the degree to which a drug or other substance becomes available to the target tissue after administration. Both the pharmacokinetics and bioavailability of resveratrol are still inconclusive.  Studies in mice, rats and dogs have consistently shown that resveratrol can be absorbed and distributed in the blood stream at relatively high concentrations. However, due to its rapid metabolism and elimination from the human body, the potential impact of resveratrol on humans is debatable. There are a few major problems with resveratrol:

First, humans who receive an oral dose have plasma concentrations of resveratrol that peak after only 30 or 60 minutes.  This shows that resveratrol is indeed metabolized quickly and may not be able to exert its positive effects before being metabolized.

Second, the dose of resveratrol needed to experience positive health effects remains unclear. Sirtris Pharmaceuticals Inc. is using very high doses in phase II clinical trials (2500 mg and 5000 mg per day) of this drug for diabetes. However, other scientists believe resveratrol supplements should be taken in lower doses. No other human clinical trials or studies have been conducted in order to determine the amount of resveratrol needed to exert its positive effects. The amount of resveratrol in a bottle of red wine can vary between types of grapes and growing seasons, and can vary between 0.2 and 5.8 milligrams per liter. While some research suggests that drinking a moderate amount of red wine (1 to 3 glasses a day) may provide enough of the active compound to exert protective effects, controlled scientific studies have not been undertaken to verify this hypothesis. Although resveratrol can be concentrated and obtained in capsule form, taking these supplements may not have the same effect as drinking red wine, primarily due to the reason explained below.

Third, resveratrol degrades quickly when it is exposed to oxygen. For example, resveratrol is no longer active in wine if the bottle has been opened for 24 hours. This directly applies to the manufacturing of resveratrol supplements, which are most likely exposed to air during the manufacturing process or storage. This presents an obstacle to supplement preparation and necessitates careful handling of the substance. It is very likely that the majority of marketed preparations of resveratrol do not contain the active form that is found in red wine.

While a few phase I clinical trials have shown that resveratrol is safe in certain doses for healthy participants and people with type II diabetes, many more clinical trials on humans are necessary before conclusions can be made regarding the effects of resveratrol in the context of neurodegenerative diseases such as Huntington’s disease.


Resveratrol has been shown to have wide-ranging positive effects on many diseases. Research has revealed resveratrol’s ability to protect against some of the common HD complications by decreasing inflammation, combating oxidative stress, increasing the energy production in cells, and potentially reducing huntingtin protein aggregates. However, it is important to note that nearly all of the research on resveratrol has been done in cell culture and in mice, and this data may not necessarily apply to humans. As more studies are conducted regarding the mechanism of resveratrol, the amount necessary in human body in order to have protective effects, and the effects of resveratrol supplements in humans, we will have a better idea about how resveratrol works and whether it will be an effective treatment for patients with neurodegenerative diseases such as HD.

For further reading^

-D. McGee, 01/11/05, and P. Bakhai, 6/19/10


Talking to Children About Huntington's Disease






Families choose to discuss Huntington’s disease with children in different ways according to their personal beliefs about how best to handle this information. This article does not intend to imply that there is one right way to speak with children about this very difficult subject. The following information is based on the experiences of social workers and the families with HD with whom they have worked. Hopefully it can provide a starting point for communication, and can be adapted to individual families and circumstances.


Talking about HD is difficult because it is a complex diagnosis and it can have a profound and devastating impact on family dynamics. Parents often believe that HD is too complicated for an infant to understand, and too distressing for school age and adolescent children. In addition, the already challenging task of telling a child about his or her parent’s chronic illness is amplified in the case of HD, because the child is at risk of inheriting the disease. Caregivers fear that their child will someday develop symptoms of HD and want desperately to provide him or her with a normal childhood, free from the anxiety, sadness, and anger that living with HD entails. Moreover, some parents worry that by telling their child about HD, they will subject him or her to genetic discrimination, which could limit social relationships and opportunities. Despite all of these concerns, most families and social workers agree that establishing open and honest communication about HD from a young age, rather than avoiding this topic altogether, is less damaging and more beneficial for all members of the family.

While keeping quiet about HD in the family seems like a way to protect a child, it often does more harm than good. Even when the condition is not discussed, small children commonly pick up on the notion that parents are anxious and worried, and that something is wrong with the parent with HD. If the diagnosis is not at least explained in simple terms to the child, he or she might feel responsible for causing the strange behavior of the affected parent. In addition, a common symptom of HD is irritability. If a parent’s irritable behavior is not explained properly, a child may not understand that the parent’s anger is not directed at him. Inability to discuss HD can also eventually lead to poor preparation for future changes in the family as the symptoms of the parent with HD grow more severe.

Talking to a child about HD helps the child understand why his mom or dad is acting strangely and can make it easier for the whole family to cope with the diagnosis. Open communication creates a safe environment to discuss and ask questions about a very distressing illness, and it reduces individual feelings of isolation for the child as well as the stress of secrecy for the parents.

When do I tell my child about HD?^

Most social workers who work closely with families with HD believe that children should be told at any and every age. It is never too early and never too late to discuss HD with a child. Children are surprisingly resilient and often have a greater than expected capacity to cope with such disturbing news. Children who sense already that something is wrong with a parent may actually feel relieved to hear facts about HD because these are sometimes more hopeful than their fears. The information given to children about HD will clearly be more basic for those who are younger, but evidence based on adoptive studies indicates that the younger the child is when told about the diagnosis in the family, the easier it will be to cope in the long run. This is because the child will begin to integrate this information as part of his life so early that it will seem more normal and therefore less scary. It is helpful to know that the talk itself is often less stressful than the anticipation leading up to it.

How do I tell my child about HD?^

When first discussing HD with a child, it is important to tailor the discussion appropriately to age level. If there is more than one child in the family, it may be important to speak to each of them separately, giving more details to those who are older. However, it is a good idea to begin the basic discussion with the entire family present to establish trust and make sure that nobody feels left out. While the first conversation about HD is often the most stressful for the parent, it is important to keep in mind that it is the first discussion of many. The topic will need to be revisited periodically to make sure that children have the most updated information, to give them the opportunity to ask questions, and to make sure they are coping in a healthy way.

When talking about HD, it is necessary to keep in mind the developmental level of the child and to gauge how much to say about HD by disclosing information gradually. HD is a complicated illness and abstract thinking does not develop until adolescence. Before then, complex discussions about this condition will only confuse the child.

When having this discussion, parents need to offer children reassurance and leave them with a sense of hope. In addition to worrying a lot about the parent with HD, children will often be concerned about what will happen when the parent’s symptoms get worse. It is important to assure children that no matter what, there will always be someone to care for them. It is also important to leave children with a sense of hope. Parents need to emphasize that doctors and researchers are working hard every day to improve therapies and to find a cure for HD.


There are some things to remember not to do when discussing HD with children. First and foremost, the parent should never lie. Lying takes a lot of energy and it can become complicated to lie about certain pieces of information for extended periods of time. A lie is difficult to remember and ever-changing explanations lead to disbelief and mistrust. Honesty fosters trust and a sense of security, both of which can enable open discussion and make coping with HD as a family much more manageable.

The scientific and medical information related to HD is complicated and will be too difficult for small children to understand. Therefore, when talking to young children, the parent must be conscious not to overburden them with too much medical information after explaining the diagnosis in basic terms. If the parent is trying to answer a child’s question, it is a good idea for him or her to ask if the child understands or has additional questions. If the child wants more information, then the parent should elaborate.

It is important for the parent not to make promises that cannot be kept, thus giving the child a sense of false hope that may someday be devastating to the child. For example, if the child has not been tested for HD, the parent cannot promise that the child will never develop symptoms of this disease. The parent should inform the child that such a test is possible and could be considered after age 18.

Parents should not be afraid to say that they don’t know the answer to a question. Not knowing may mean that the individual parent doesn’t have the answer to a question but can find somebody who does. It may also mean that nobody knows the answer to the question and this is also perfectly okay. For example, no one knows exactly when there will be a cure for HD. We all hope that it is soon, but no one knows at least for now and the child is not alone in waiting for an answer.

Talking about HD with specific age groups^

As mentioned previously, the information parents give to a child about HD should be appropriate to the child’s age. There will likely be individual differences in suitable information depending on the child’s maturity level, but the following provides a general frame of reference for age-appropriate discussion.

When talking to preschoolers, children ages 2-5, parents should use language that their children understand and keep their explanations short. Children this age may begin to show signs of anxiety, so it is often helpful for parents to let them know the ways in which they are keeping their daily routines the same, in spite of having HD in the family. Routine can be very soothing, even for small children, and so emphasizing this creates comfort that their lives aren’t changing too much all at once. This gives the children space to integrate the new information they receive on HD and therefore to cope. For children in the older portion of this age range, it should be made clear that nothing they did caused HD. This is important because children around this age are prone to magical thinking, believing that they have the ability to make certain things happen, simply by wishing for either good or bad things. If a child does not understand why the parent has HD, the child may attribute the symptoms to his or her wish, resulting in a profound sense of guilt.

School age children, children ages 6-11, are generally capable of understanding a basic explanation of the disease. It often helps to give the child the name of the disease and to point out that you cannot catch it by hugging or sharing food with the individual who has it. It is also a good idea to give the child an overview of what doctors are doing to control the symptoms of HD even though there is, as of yet, no cure. It is important for parents to realize that children in this age range can become overly concerned with health and that it is possible that if they are given too much information, they may worry about HD well before the onset of specific symptoms.

Teenagers are generally very capable of understanding a lot about HD. Because of this, parents should be open and willing to give as much detailed information as the teen needs to understand the illness. Most agree that at this point, parents should answer all questions, including ones about transmission, as fully and as honestly as possible. However, this stage of life is often difficult because of the many physical and psychological changes that emerge as part of adolescence. This is a time when individuals formulate and strengthen their self-identities and establish important peer and other relationships. Often teens are prone to mood swings, anxiety and depression and may become angry or withdrawn when HD is discussed. If this is the case, it is important for the parent not to force the teen to talk about HD, but to make himself or herself available when and if the adolescent should decide to talk about the condition. At this point, it is also helpful to have an open discussion about stigma associated with HD and how people are often afraid of behavior that seems different or that they don’t understand.

In conclusion^

Deciding when and how to talk to children about HD may involve significant mental preparation. The above can be considered as a starting place for parents who want ideas as to where to begin. One helpful idea is for the parent with HD to think about how HD was discussed when he or she was growing up and to consider whether or not it was an effective way to deal with the diagnosis and what, if anything, he or she might have changed. Drawing from personal experience might make it easier for the parent to communicate information about HD.

Social Workers Bonnie Hennig, author of Talking with Kids About HD, and Rick Henry of the HDSA Center of Excellence at University of California Davis Medical Center, were instrumental in the writing of this article. They are helpful contact persons for more detailed and personalized guidance.

Recommended Resources and Links for Children^

For Further Reading:^

  • Hennig, Bonnie. Talking to Kids About HD. 2004.
    This book provides information about how to discuss HD with children at different developmental stages. It is the basis for much of the information in this article.
  • Keenen, K. et al. “Young people’s experiences of growing up in a family affected by Huntington’s disease.” Clinical Genetics 71 (2007): 120-129.
    This article examines the experiences of young people in families affected by HD. It cites knowing about HD from an early age in particular as a factor in coping effectively with the illness in the family.
  • Lefebvre, A. “Talking to children about HD in the family.” Horizon Newsletter. Winter, 1999. Online here.
    This article discusses some ways of approaching HD with different age groups. It is short and easy to read.
  • Lowit, A. and van Teijlingen, E.R. “Avoidance as a strategy of (not) coping: qualitative interviews with carers of Huntington’s Disease patients.” BMC Family Practice 6 (2005). Online here.
    This study involved interviews of ten carers of spouses with HD. Although the number of participants is small, the article discusses interesting insights into the psychosocial impact of not discussing HD within the family.

– A. Frohnmayer, 5/22/09


Physical Exercise




Everywhere we turn, we hear information about the benefits of exercise. From building stronger bones and muscles to reducing the risk of diseases such as diabetes and heart disease, the effects of physical exercise on general health are certainly far-ranging. In fact, a growing body of research is demonstrating that physical exercise is good for your body as well as your brain. Recent examinations of the link between physical exercise and the central nervous system have shown positive effects on a wide range of brain health markers. So, in addition to the obvious reasons to exercise – such as maintaining a trim physique and a healthy heart – there is also the added benefit of keeping your brain healthy, which can lead to increases in cognition and memory. On a broad level, exercise is essential for maintaining good blood flow to the brain and increasing the brain’s consumption of oxygen and glucose. On a more specific level, exercise appears to have profound effects on specific molecular systems involved in the regulation of neuroplasticity. Together, these effects result in a well-preserved brain that is more adaptive to change.

The purpose of this chapter is to provide information about the benefits of physical exercise and to explore how this life practice may affect the way that individuals respond to HD. Exercise, especially for people with HD who experience significant brain loss as well as a variety of health-debilitating symptoms, is an excellent life practice because it proactively addresses health on a variety of fronts.

Exercise and Capillary Density^

In general, exercise improves the heart’s ability to pump blood and increases the natural ability of blood to carry oxygen to cells throughout the body. With exercise, blood circulation to the brain is thus increased and the brain receives more oxygen and glucose, both of which are crucial to brain function. The brain is the body’s most active organ and it requires the most energy. Although it accounts for only 2% of our body weight, it uses between 20% and 30% of the body’s energy. Despite this need for a large amount of energy, the brain can not store any oxygen or glucose. It is therefore necessary for the blood stream to deliver a constant supply of these essential substances, and it does this by circulating continuously through the brain. A person can feel a lack of oxygen after only a few seconds. When you stand up too quickly and become dizzy, this is an example of loss of blood flow to the brain that can be sensed. Diabetics who give themselves too much insulin can drop their blood sugar level and faint, and can die unless they quickly increase the level of glucose in the brain. Adequate blood circulation and the vast network of blood vessels that serve the brain and allow for blood flow are thus critical. The 400 miles of blood vessels in the human brain have a surface area of approximately 100 square feet. The health of these vessel walls is very important for proper brain function. In addition to delivering a constant supply of oxygen, glucose, and other important nutrients to the brain, blood flow to and from the brain also removes harmful toxins. So overall, having a proper functioning vascular (blood vessel) system is absolutely necessary for optimal brain health and functioning.

When blood flow to the brain is increased, the body responds by forming new blood vessels to bring the extra blood to nerve cells. This process, known as angiogenesis, is directly connected to neurogenesis, the process of making new nerve cells. It was initially believed that angiogenesis, much like neurogenesis, was limited to certain periods of development or in response to pathological insults. It has since been discovered that angiogenesis naturally occurs when physical activity is increased, and can be induced by exposure to a complex environment or exercise. Thus, the formation of new blood vessels is not restricted to developmental periods but extends into mature adulthood and beyond. For example, in the dentate gyrus, a brain structure that experiences a great amount of neurodegeneration on account of HD, new nerve cells are clustered close to blood vessels. These nerve cells can only grow and be healthy when there is enough blood flow to the brain. Researchers believe that decreased blood flow to the brain as a result of fewer blood vessels contributes to the decline in new cell production among older individuals. Moreover, exercise has been shown to increase angiogenesis and nerve cell proliferation throughout the brain in various animal models like mice and fruit flies.

It turns out that there is a good reason why exercise seems to “clear your head.” Your heart rate increases as you exercise, increasing blood flow to the brain, which enhances waste removal and provides much-needed oxygen and glucose. In a test, students had a one-minute blast of oxygen given to them immediately before being given a list of words to remember. On average, the students who took the oxygen remembered two to three more words from a list of 15 than those who did not. Students who took oxygen while playing the Tetris computer game on its most demanding level were also shown to play significantly better. Exercise can act very similarly to having a one minute blast of oxygen. If performed on a consistent basis, exercise has the effect of providing a dose of continuous oxygen to the brain, such that the cognitive boosts can be continually maintained as well. The increase in blood circulation because of exercise can induce the formation of new blood vessels that can, in turn, facilitate the creation of new nerve cells.

Exercise and Cognitive Maintenance^

Even people who do not have HD experience a moderate amount of neurodegeneration as part of the normal aging process. Here, the signals that nerve cells use to communicate with one another become less powerful and less efficient. This decreased ability for nerve cells to communicate makes it harder for the brain to adapt to outside influences and generate new nerve cells. The inability to create new nerve cells leads to losses in brain tissue and impaired functioning. Indeed, imaging studies in elderly humans have shown some noticeable atrophy in the brain. In people with HD, this atrophy is substantially magnified. One of the consequences of atrophy is that older adults typically perform more poorly than younger adults on a broad range of cognitive measures. (For more information on cognitive symptoms of HD, click here)

Despite such declines in cognitive and motor processes during the course of aging in people with HD, recent findings suggest that physical exercise can minimize some, but not all, kinds of cognitive decline. A recent study showed that older adults who exercised throughout life had less brain tissue loss and performed significantly better on cognitive tests than adults who exercised infrequently. Similarly, a study with twins done in Sweden found that the twin who exercised more was also more likely to score higher on a cognitive test. It is important to note that these tests show correlation and do not necessarily prove causation. In other words, just because people who exercise a lot show increased cognitive abilities, this does not necessarily mean that one causes the other. For example, people who exercise more may also have better eating habits such that improved nutrition leads to better cognitive scores. Nevertheless, as indicated by the numerous studies discussed below, the role of exercise in cognitive maintenance should not be discounted.

It turns out that the areas in the brain that are associated with mental decline due to aging are the same areas that are the most responsive to exercise. Researchers have found that people who exercise a lot have more gray matter and white matter in the brain, particularly in the frontal lobe, temporal lobe, and parietal lobe. The lobes of the brain are composed of gray matter and white matter. Gray matter is where all the nerve centers are located. White matter connects the gray matter together. (For more information about the brain and its structures, click here.) The amount of gray matter and white matter declines naturally, affecting the functioning of the lobes and contributing to a decline in cognitive functioning and processing ability.

It has been found that individuals with HD typically have a substantially reduced volume of gray matter and white matter in the brain, especially in the temporal lobe and the frontal lobe. This is significant, given the prominent roles that each of these lobes play in the cognitive processes. The frontal lobes of the brain have a lot to do with what people call higher-level cognition, where we synthesize information, and store data we’ve just acquired. If the frontal lobes are not functioning properly, then you can easily forget a phone number you just looked up or the name of a person you just met. The temporal lobes consolidate short-term memories and build them into long-term memories. Damage to temporal lobes can also result in altered personality and affective behavior. The parietal lobes allow us to construct a spatial coordinate system to represent the world around us. Damage to the parietal lobes can result in neglecting part of the body or space, which can impair many self-care skills such as dressing and washing. (For more information about the lobes of the brain, click here.) Deterioration of each of these lobes is associated with some sort of mental decline. Exercise appears to exert its effects partially by protecting against a loss of gray matter and white matter, thereby preserving the structure and function of the lobes in the brain. With the lobes able to function better, the onset and progression of various cognitive deficits are likely to be delayed.

The fact that some degree of neurodegeneration is part of the normal aging process means that a person with HD must deal with these changes in addition to disease-related loss. Preserving cognitive function and preventing mental decline is definitely an uphill battle and some amount of neurodegeneration is inevitable. But this does not mean that the situation is hopeless. Studies on exercise reveal that it may indeed play an influential role in slowing down cognitive decline. As the rest of this chapter reveals, exercise exerts numerous other beneficial effects throughout the body and is thus a wonderful practice to incorporate into the daily routine. Later in this chapter, we’ll give some suggestions for where to begin.


In addition to keeping the brain’s lobes healthier and more intact, physical exercise can act directly on the brain’s molecular machinery. There is increasing recognition that physical activity can help relieve the effects of deterioration of nerve cell function. Numerous scientific studies with animals have reported that voluntary exercise leads to an increase in production of Brain-Derived Neurotrophic Factor (BDNF). This is a kind of protein that aids in the growth and survival of nerve cells during development, and in the maintenance of adult nerve cells. Because BDNF has both neurotrophic and neuroprotective properties, it is able to significantly influence brain plasticity. (For more information on BDNF, click here.)

HD invariably leads to decreased levels of BDNF, leaving nerve cells more vulnerable and prone to injury or death. In people without HD who have the normal huntingtin protein, the huntingtin protein indirectly activates the promoter, or the “on” switch, of the gene that encodes BDNF. When this gene is turned on, it prompts nerve cells to make more BDNF. In people who have HD, mutant huntingtin indirectly inactivates the “on” switch so that BDNF can no longer be produced. In the absence of BDNF, the cell’s ability to survive is markedly decreased.

Currently, scientists are looking for ways to harness neurotrophic factors such as BDNF so they can be administered to patients. This treatment would theoretically improve the symptoms of people with neurological disorders because it would dramatically improve the health and survival of the person’s nerve cells. Animal studies and in vitro models both indicate that BDNF is capable of making damaged nerve cells regrow. Because of this capability, BDNF represents an exciting possibility for reversing brain disorders, such as HD. The fascinating part of BDNF is that the protein can naturally be increased through exercise. In one rat study, several days of voluntary wheel-running increased levels of BDNF. The changes in BDNF levels were found in nerve cells within days in both male and female rats and were sustained for several weeks after exercise.

In particular, running activity increases levels of BDNF in the lumbar spinal cord, cerebellum, and cortex, but not in the striatum. Since the main site of neurodegeneration in people with HD is the striatum, exercise alone will likely not be able to prevent many of the symptoms of the disease. However, exercise can help preserve cognitive function and promote the general health of the brain, as well as the general health of the body overall. Although exercise may not be able to promote neurogenesis (the growth of nerve cells) in the striatum, it may promote neurogenesis in other areas of the brain and body by increasing the vitality of nerve cells. These changes may be enough to delay the onset and progression of various HD symptoms.


Exercise and Stress Alleviation^

Exercise may also help the brain to better cope with stress. Stress leads to the release of various neurochemicals and stress hormones. (For more information on stress and its effects on the brain, click here.) Prolonged exposure to stress hormones is detrimental to the health and survival of nerve cells. Normal nerve cells are like miniature trees with a lot of branches. These “branches” are called dendrites. They are structures that connect one nerve cell to many other nerve cells. Stress hormones cause the branches of the dendrites to become shorter and less widespread, such that the affected nerve cell cannot connect to as many nerve cells. With fewer connections, it does not receive as much information as it should, and becomes more prone to injury or death. It is thought that this effect occurs mainly because stress hormones decrease the amount of BDNF in the brain, depriving nerve cells of neurotrophic factors necessary for growth and survival. Exercise directly counteracts this effect by increasing BDNF availability in the brain. As evidence, in a study in which two groups of rats were exposed to stressful stimuli, the effect of exposure to this stress was mediated by exercise. Rats that were able exercise before exposure to the stressful stimuli had normal amounts of BDNF in the brain, whereas rats that were not able to exercise had significantly decreased amounts of BDNF in the brain.

In addition to increasing BDNF availability, exercise also helps regulate the release of harmful stress hormones, so that they don’t flood into the nerve cells and wreak havoc. Researchers first became interested in exploring a possible link between exercise and stress after discovering that physically fit individuals have significantly lowered rates of anxiety and depression. Although popular theory states that exercise causes a rush of endorphins, there is very little evidence for this phenomena. Instead, researchers believe that a chemical known as norepinephrine plays a key role in helping the brain deal with stress more efficiently. During exercise, norephinephrine is released and goes on to directly increase heart rate, release energy from fat, and increase muscle readiness. Studies in animals since the late 1980’s have found that exercise increases concentrations of norepinephrine in regions of the brain involved in the body’s stress response. Although the exact mechanism is not known, increased norepinephrine in the brain is thought to decrease the release of other harmful stress chemicals. In fact, some antidepressants work by increasing brain concentrations of norepinephrine.

Many physiologists believe that exercise also enhances the body’s ability to respond to stress in a more general way. Biologically, exercise seems to give the body a chance to practice dealing with stress. It forces the body’s physiological systems, all of which are involved in the stress response, to communicate much more closely than usual; e.g. the cardiovascular system communicates with the renal system, which communicates with the muscular system. All are controlled by the central nervous system and sympathetic nervous system, which must also communicate with each other. This “workout” of the body’s communication system may be the true value of exercise; the more sedentary we get, the less efficient our bodies become in responding to stress.

Biological evolution of exercise^

The widespread effects of exercise should not be surprising considering that the human body evolved in an environment of regular physical activity. Biologically, it was part of survival. Physical capability was necessary for success at hunting, gathering food, and providing shelter and safety. What is now considered a form of exercise – walking – was originally a form of transportation.

Today, many people see physical movement as an optional part of their lifestyles. This type of thinking is unfortunate considering the integral role that exercise plays, not only in general health, but also numerous cellular and molecular cascades that protect the brain. Not surprisingly, a lack of exercise is linked to increased incidence of many diseases. Additionally, the ability to perform day-to-day activities declines: to walk without falling, to rise from a chair or get in and out of a car unaided, to carry a bag of groceries, to tie shoes, etc. Although human lifestyles have changed, and exercise is no longer a necessary part of our daily survival, our bodies still need exercise. We must consciously make an effort to incorporate some sort of physical activity into our daily life routine.

Exercise and HD^

During the progression of HD, a person will decline in health and be forced to lead a more sedentary lifestyle. Although the disease process can’t be altered, a routine exercise program can help to address many areas of decline, as well as increase strength, improve balance and posture, and allow the individual to feel more in control of his/her body. Aerobic activity, such as pedaling, jogging, or walking, may improve breathing, which in turn may help with breath control for talking and eating. Improvement in deep breathing will also help maintain the ability to cough effectively, which helps prevent choking and aspiration pneumonia. Regular exercise also makes it easier for people to clear secretions more efficiently when they do have colds or pneumonia. Growing evidence shows that physical exercise does not have to be strenuous or even require a major time commitment. It is most effective when done regularly, and in combination with a brain-healthy diet, mental activity, and social interaction.

Getting Started^

Physical activity is any bodily movement that burns calories, such as gardening, vacuuming, shoveling snow, walking to the store, climbing stairs, or playing ball with your grandchildren. As such, anyone can improve their physical fitness, regardless of age or physical condition. In fact, the greatest improvements are often seen among the frailest individuals who are nurtured through an exercise program. The easiest, safest, and most readily available physical activity for a person with HD is walking. It can be combined with a purposeful activity, such as walking a dog, pushing a person in a wheelchair, walking to the store to buy a newspaper or groceries, or picking up trash in the neighborhood.

Convincing people of the benefits of exercise is an essential first step. Many people with HD are worried about becoming a burden to their families. Explaining that exercise can help keep them healthy and make caregiving easier on their loved ones can be a strong selling point. But it is first important to consult with a physician before embarking on an exercise program. A health history and physical may reveal cardiac, musculoskeletal, or other problems that may impose restrictions on the type and intensity of exercise to be undertaken. If this is the case, request a referral to a physical therapist or cardiac-rehab specialist to work out a beginning regimen that is suitable for the individual. It may help to ask the person’s physician to reinforce his or her exercise recommendation by writing out a prescription that can be shown to the individual periodically. Such an instruction carries more weight than suggestions from a caregiver. The key to motivating people to persevere in any program of lifestyle change is social support. Fitness club membership lists are filled with names of people who rarely come to work out after an initial “honeymoon” period. Many home treadmills, exercise bikes, and other fad equipment are unused after this initial period. Exercise programs for persons with disabilities that are successful are all characterized by the presence of exercise “buddies” or program monitors that provide ongoing supervision and encouragement.

For further reading^

  1. “Advanced Stages of Huntington’s Disease Caregivers Handbook: Exercise and Fitness.”
    This is a Huntington’s Disease Handbook that has a chapter on exercise that discussed the importance of exercise and discusses sample exercise plans.
  2. Bloor, CM. (2005). “Angiogenesis during exercise and training.” Angiogenesis 8(3): 263-71.
    This technical article thoroughly examines the link between angiogenesis and physical activity.
  3. White, L. (2005). “Exercise and Cognitive Function.” The Lancet Neurology. 4(11): 690-691.
    This article explains the ways in which exercise can impact cognitive function.

-D. McGee, 4-30-06; recorded by B. Tatum, 8/21/12


Physical Therapy and Huntington's Disease Treatment and Management



The onset of Huntington’s disease (HD) is heralded by a wide range of symptoms, from behavioral ones, such as depression and irritability, to physically visible ones, such as bodily tremors, bradykinesia, akinesia, and dysphagia. As the disease advances, symptoms become progressively severe. Physical symptoms, such as involuntary movements, worsen, potentially leading to frequent falls. Although there is currently no cure for HD, there are many treatment regimens that may help slow the progression of symptoms. While most research is aimed at developing drugs and medications to help alleviate HD symptoms, physical therapy interventions also have the potential to improve the quality of life for many patients.

There are three main types of physical therapy: physio-, occupational, and speech. Although there is overlap between these treatments, each type of therapy differs slightly in its goals and how it works.

Types of Physical Therapy^

Physiotherapy is physical therapy that focuses primarily on the control of larger bodily motions, such as walking and standing. Occupational rehabilitation aims for ‘adaptive’ improvement—learning new ways to accomplish day-to-day tasks involving fine motor skills made difficult by HD symptoms. Speech therapy deals with the patient’s physical difficulties involving mouth and throat muscles, and the process of speaking. Below is a table summarizing some of the major components that each type of therapy addresses:

Physiotherapy Occupational Therapy Speech Therapy
  • Gait and balance
  • Fall prevention
  • Aerobic capacity
  • Muscle strength
  • Wheelchair prescription and training
  • Respiratory function
  • Task-specific reach, grasp, and manipulation
  • Personal hygiene
  • Grooming and dressing
  • Eating and drinking
  • Toileting
  • Work restructuring
  • Driving assessment
  • Memory training
  • Provision of adaptive devices
  • Speech intelligibility- control of rate and volume
  • Intonation
  • Speech rhythm
  • Swallowing
  • Eating
  • Respiration
  • Language comprehension

Physiotherapy involves several large areas of rehabilitation. It may focus on gait, balance transfers, general strengthening, coordination, and postural stability. Many different types of exercises are performed in this type of treatment, as each patient’s individual exercise regime will vary depending on his or her specific needs. The different exercises focus on training different areas of the body, but all aim to prevent falls, promote correct walking and body control, build coordination, and encourage a positive and confident attitude towards the body. Exercises are done in a variety of positions—lying down, sitting, and standing. Some exercises make use of common gym props and machines such as exercise bicycles, treadmills, weighted balls, and dumbbells, while others focus on flexibility or posture training. In posture training, exercises help patients maintain good form and balance while moving and staying still. For example, a patient may be asked to focus on transferring body weight from one leg to the other or to walk with hands clasped behind the back.

Like physiotherapy, occupational therapy is individually tailored. This type of rehabilitation integrates both mental and physical exercises to aid patients in learning new strategies to accomplish tasks that become more challenging as HD progresses. Activities focus on memory stimulation and concentration as patients learn approaches for completing common tasks such as walking or standing safely, dressing, and personal hygiene. Oftentimes, an occupational therapist will also aid in assessing whether or not it is practical and safe for a patient with HD to continue driving, and also in recommending changes in the work environment to better accommodate the progressive symptoms of HD.

Speech therapy attempts to help patients regain or maintain verbal adeptness, and other skills related to the mouth and throat. Respiratory exercises such as blowing up balls and blowing on tissues at different distances aim to increase the efficiency of breathing. On the cognitive side of speech rehabilitation, patients complete exercises which test and strengthen their ability to understand, interpret, and use metaphors, synonyms and other figures of speech.

Effectiveness of Physical Therapy^

One study tracked 40 patients with HD over two years as they followed a comprehensive rehabilitation program. The regime included both the physical and cognitive aspects from physiotherapy, occupational therapy, and speech therapy. The findings showed that over time, physical therapy had positive effects on motor and functional performance. Moreover, cognitive abilities did not decline as would be otherwise expected. These results indicate that patients are able to, at the very least, maintain a constant level of functional, motor, and cognitive performance over two years with the help of physical therapy This is important because HD is characterized by a deterioration of these abilities. However, the problem with this type of study is the lack of control groups, and difficulty in quantifying progress in the absence of any common standards.

Despite the evidence indicating that physical therapy can help people with HD maintain independence and functional capacity, recent research suggests that it is not always routinely provided. One survey revealed that only 24% of patients with HD had worked with an occupational therapist, only 8% had been seen by a physiotherapist, and close to none had been contacted by a speech therapist. Although it is unknown why physical rehabilitation services are so rarely used by patients, several explanations have been proposed. One reason may be the fact that there are very few studies that quantify the effectiveness of such treatments. Another possible reason for the limited use of rehabilitation services is reluctance in the community of service providers to accept people who are afflicted with a progressive condition, because it is thought that their chances of improvement are exceedingly low.

If more rigorous studies are completed that definitely demonstrate the effectiveness of physical therapies in slowing disease progression and improving patient quality of life, perhaps these types of treatments will be recommended to HD patients in the future.

Further reading:^

  • Bilney, B., M. Morris, and A. Perry (2003). “Effectiveness of Physiotherapy, Occupational Therapy, and Speech Pathology for People with Huntington’s Disease: A Systematic Review.” Neurorehabilitation and Neural Repair 17:12-24.
    Less technical review which outlines many of the current treatments. Provided inspiration for the table in the “Types of Physical Therapy” section.
  • Busse, M.E, and A.E. Rosser (2007). “Can directed activity improve mobility in Huntington’s disease?” Brain Research Bulletin 72:172-174.
    Short, less technical review which summarizes some of the research that has been done in the field so far.
  • Zinzi, P., D. Salmaso, R. De Grandis, G. Graziani, S. Maceroni, A. Bentivoglio, P. Zappata, M. Frontali, and G. Jacopini (2007). “Effects of an intensive rehabilitation programme on patients with Huntington’s disease: a pilot study.” Clinical Rehabilitation 21:603-613.
    A technical paper which outlines a study on how rehabilitation affected patients over a longer time span. Data mentioned in the “Effectiveness of Physical Therapy” section was drawn from this study.

– A. Pipathsouk, 4/12/2009