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Assistive Technology Projects - Development of Prototypes

James Anderson, JEM; David A. Brown, PhD, PT; Charles G. Burgar, MD; Deane Denney; Arden Farey; Vincent R. Hentz, MD; David L. Jaffe, MS; Deborah Kenney, MS, OTR; Maurice LeBlanc, MS; Stephanie O'Leary, MS, OTR; Eric E. Sabelman, PhD; Alvin Sacks, PhD; Douglas Schwandt, MS; Jaime S. Vargas, MS; Peter Werner, MD; Conal B. Wilmot, MD

Technology Transfer Guidelines


This document was prepared in an effort to assist and inform those in the DVA who have responsibility for the transfer of technology from laboratory to manufacturer. The guidelines organize and integrate relevant technology transfer material. Appendices include references to the Federal Technology Transfer Act, other pertinent legislation, Cooperative R&D Agreements and Disclosure of Invention forms.

Thumb Control Environmental Control Interface

Jaffe, Burgar


The Thumb Control is a single switch input environmental control interface for an inpatient veteran with a brain stem injury. The user controls the system's operation with a glove-mounted microswitch. The interface then operates the nurse call, television, stereo, lamp, and computer. This system provides backup to a commercial environmental control system (Ke:NX by Don Johnston) which is used to run Macintosh computer programs, communicate with family and staff, and access the Internet and World Wide Web. The main unit resides on an over-bed table, has a backlit LCD display for night operation, and is constructed around an inexpensive battery-powered microcontroller. Unique features of this device include user control over many of its operational parameters including scan rate, dwell time, and audio feedback as well as its ability to reboot the Macintosh and activate the nurse call in the event of a computer failure. While this initial prototype is a dedicated unit for a specific individual, its features can be generalized for use by others and incorporated into future commercial units.

Figure - Thumb Control Environmental Control Interface.

Ultrasonic Head Control Interface


The Ultrasonic Head Control Unit is an interface serving people without control of their arms or legs. The user's head position is calculated from ranging data provided by two Polaroid ultrasonic transducers. The head position information is then used for the realtime control of an electric wheelchair or a computer's mouse. Tilts of the user's head off the vertical axis (forward-backward, left-right) operate the wheelchair or move the screen cursor. The primary advantage of this device is that it requires no mechanical contact between the transducers and the user's head. The user, therefore, does not feel "wired up". The interface is intuitive to use, unobtrusive, cosmetically pleasing, and socially acceptable. Within the VA, the Technology Transfer Section in Baltimore has completed a nationwide clinical study of commercial prototype wheelchairs equipped with the interface (from Eureka Labs in Sacramento) and is now funding a cooperative effort with the Cerebral Palsy Research Foundation of Kansas to move this technology to the marketplace.

ERGO Knife

Kenney, LeBlanc, Anderson


The ERGO Knife is an ergonomic replacement for the utility knife. Its design alleviates the often uncomfortable and tiring positions of a regular utility knife and allows safe and easy cutting of flat materials, even while seated. The ERGO knife is ideal for cutting heavy duty materials such as cardboard. Originally designed to aid therapists in cutting splint plastic, it also fits a variety of industrial applications and home needs for both able bodied and disabled users. Corporate partners are currently being sought for commercialization of this product.

Figure - The ERGO knife cutting a plastic sheet

SkillSet Office Tools

Vargas, Anderson, Denney, O'Leary


SkillSet is a family of inexpensive tools that help people with limited hand function work effectively in the modern office environment. Included are devices for handling diskettes, papers, paper clips, file folders, paperfolding, and staple removing. SkillSet can enhance the productivity and independence of office workers, professionals, students - anyone who works with documents or computers. Each tool in the SkillSet is designed around a specific task, making it easy to build customized tool kits. SkillSet tools work with standard office equipment and supplies, making them an attractive investment for employers wishing to meet ADA requirements cost-effectively.

Clinical testing in the Spinal Cord Injury Service will assess SkillSet's usefulness and market potential. Commercial partners are being sought to manufacture and distribute SkillSet.

Figure - SkillSet's diskette handling tool

Beverage Dispenser

Anderson, O'Leary


Persons with quadriplegia typically do not have use of their arms or hands so they depend on others to help them drink. This is a labor intensive task for caregivers and can diminish the user's independence and self esteem.

The Beverage Dispenser provides individuals with quadriplegia a means to drink on their own. The dispenser consists of two major pieces. The first is a cloth bag that holds a closed beverage container and hangs by straps on the back of the user's wheelchair, out of the way. The gravity support prevents spills when the chair is reclined. The second element is a fully adjustable piece of plastic tubing that supports the straw from the beverage container to the vicinity of the user's mouth. The caregiver only has to load the cloth bag with the beverage of choice and position the tubing. The product is currently in the field evaluation stage. Upon successful completion of clinical trials, the product design will be offered to manufacturer/marketing vendors for commercialization.

Figure - The beverage dispenser mounted on the back of the wheelchair.

Crutch Caddies

LeBlanc, Kenney


When using forearm crutches, people with mobility impairments have difficulty carrying objects such as papers, soda cans, keys, etc. Although canvas bags for underarm crutches with double uprights are already commercially available, there are no such products for forearm crutches. We have developed crutch caddies which clip onto the tubular upright of the forearm crutch.to allow these users to carry personal objects. One caddy version is flat to carry papers; another is round to carry soda cans. After clinical testing, a technology transfer effort will seek to bring the crutch caddies to market.

Figure - The Crutch Caddy is mounted on a forearm crutch.

Wheelchair Rear-view Mirror

Schwandt, Anderson, Farey


A wheelchair rear-view mirror serves individuals who have difficulty looking behind them while backing up. The mirror is compact and unobtrusive, yet provides the user with vision toward the rear of the wheelchair, especially directly behind the large wheels. The convex mirror provides a wider field of vision than a flat mirror. Initial prototyping focused on the selection of a small mirror and on methods of attaching it to the wheelchair. A two inch diameter adhesive-backed convex mirror, commonly added to automobile side mirrors was purchased. Originally, the mirror was attached to the wheelchair using dental accessory tubing which could be shaped by hand to position the mirror correctly. Two small, black, Delrin blocks were machined to hold each end of the adjustable tubing, one block adhering to the back of the mirror with adhesive, and the other attaching to the wheelchair frame tube with wire ties. Although the dental accessory tubing was found to be too flexible, subject to vibration, and unable to hold its shape, commercially available bike helmet mirrors proved to be easily adaptable to the task. This design is currently being evaluated by wheelchair users in the Rehab R&D Center and Spinal Cord Injury Service.

Figure -A small adjustable rearview mirror mounts to a wheelchair's frame tube.

Boat Access Gangway

Schwandt, Anderson

The DDP, while evaluating the process of orphan product development, became aware of a unique accessibility problem.

People who live and work onboard a boat often require a high degree of physical dexterity and strength to board and disembark; an ability often lost after a disabling event. A veteran who suffered a stroke had a wooden staircase built which sat beside his cabin cruiser and allowed him access to his boat. But because the staircase could not go onboard, he could only leave his boat at its home dock where the staircase was permanently located. A gangway that could be attached to the captain's boat, carried aboard, and be deployed at any dock would enable him to disembark at any port that he visited.


A four step, four bar linkage aluminum staircase was designed and built. The stair treads are twenty inches wide and twelve inches deep, allowing full, stable support of the captain's feet in the event he needs to rest on any stair step. The four bar linkage attaches to a yoke that pivots on a fixed plate secured to the boat. The entire gangway can be lifted to a horizontal position and rotated ninety degrees counterclockwise to a stowed and securely fastened position on the aft side of the boat. This process takes only a few minutes. Initial results from the field evaluation of the gangway have demonstrated satisfactory operation in several locations where the boat has docked. The captain continues to live and work onboard the boat, but no longer feels trapped at dockside.

Because it is an orphan product and it is unlikely that a manufacturer would commercialize it, our intention is to make the design drawings available to others who could benefit from it. We will evaluate the response to offering the product on a do-it-yourself basis and determine whether the approach is merited for future projects. While the Rehab R&D Center does not routinely develop devices for individual patients, projects like this provide valuable insight into factors that must be considered when designing products for larger populations of persons with disabilities.

Figure - A stowable stairway provides boat access to individuals with limited mobility.

Method and Apparatus for Cyclocentric Ergometer Exercise


There are many exercise devices that are used to strengthen lower extremity muscles. It is important to find exercises for increasing strength in functional weight-bearing tasks such as walking, running, and jumping while minimizing the damage to joints that may occur with repetitive training of these tasks. Currently available bicycle ergometers, although a good exercise for minimizing joint loading stress, all involve some seating mechanism that absorbs most of the body weight forces so that weight-bearing onto the extremity is minimized. A Cyclocentric Ergometer Exercise (CEE) unit is under development that overcomes many disadvantages of currently available devices.

CEE possesses a wide range of commercial properties. Since it is easy to use and can provide training challenges to athletes as well as disabled persons, it may be made available to the general gym workout market, home exercise market, and the clinical rehabilitation market. Potentially, anyone interested in leg strengthening exercises could benefit from using CEE.

Positioning and Transfer of Acute Spinal Cord Injury Patients

Sabelman, Wilmot, Werner

The goal of this project was to design, fabricate, and test in laboratory and clinical settings equipment to improve stabilization of cervical spinal cord injury (SCI) patients during transport. SCI patients are exposed to risk of further injury by unintentional spinal motion during transport by helicopter to a specialized spinal center and during routine nursing, therapeutic, and diagnostic procedures in the hospital.


We have designed an x-ray compatible carbon fiber composite backboard and acceleration-independent cervical traction unit for transporting SCI patients. Backboard/ traction systems have been in clinical use since February, 1985, by the Stanford/Life-Flight for inter-hospital helicopter transport and by Santa Clara Valley Medical Center Dept. of Physical Medicine & Rehabilitation for in-hospital transport, and since July, 1991, by REACH/MediPlane aeromedical transport service in Santa Rosa, CA. Users report only minor problems related to counter-traction, cleaning, and traction unit height adjustment. We are exploring collaboration possibilities with the US Air Force Armstrong Laboratory, Brooks AFB, TX, in setting design and test specifications for a new generation of equipment for long-distance evacuation of military SCI casualties.

Figure - Loading (simulated) SCI patient in traction on board BK-117 helicopter.

Implantable Fingertip Touch Sensation Prosthesis

Sabelman, Hentz

Loss of touch and pressure sensation may occur as a result of spinal cord injury, brachial plexus trauma, diabetes or Hansen's disease. In order to provide protective sensation and closed-loop servocontrol of grasp force, we have studied preferred anatomical sites for implantable rather than externally mounted touch sensors. We subsequently constructed mock-up sensors small enough to be implanted, and built breadboard large-scale circuits for getting power to and touch signals from implanted sensors.


The state-of-the-art of implantable sensors has advanced to the point that transducers can be encased in glass tubes small enough to inject through a large-bore hypodermic needle. This is essentially the technology we propose to adapt: the pressure-sensing diaphragm, signal and excitation voltage-conditioning circuits and output transmitter will be constrained to fit within a 2 to 3 mm OD tube of less than 10 mm length. A scaled-up working circuit which included the pressure sensor, amplifier, transponder and antenna was built. Inductive transmission of power into the circuit was also demonstrated. Other power input and signal output transmission modes were explored, including direct wiring, radio frequency,and infrared.

Figure - Implantable pressure sensor model showing location within fingertip.

Ralph Fingerspelling Hand

Jaffe, Schwandt, Anderson


Ralph is a computer controlled electromechanical hand that serves as a tactile display for persons who are deaf and blind. In operation, the deafblind user feels the hand as it moves and interprets its motions as letters corresponding to the American One-Hand Manual Alphabet, a technique known as tactile fingerspelling. The hand is controlled by a microcontroller whose software translates incoming serial ASCII data into control signals that operate eight servo motors. These servo motors pull on the fingers' mechanical linkages causing them to flex. Ralph can use information from a computer's serial port, modem, TDD, or computer interface to a optical character recognition scanner, voice recognition system, closed caption decoder, or stenography machine facilitating translation of e-mail, telephone conversations, printed text, spoken words, subtitled television programs, or classroom/conference/courtroom interactions into fingerspelling.

Commercialization of this technology is being pursued through collaborations with an electronics company and a national research laboratory.

Figure - Ralph fingerspelling hand

Republished from the 1996 Rehabilitation R&D Center Progress Report.

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