From Sensors
September, 1998
Pages 17 - 19.


Electronic Hand Restores Movement to Paralyzed Limb 

The Freehand electronic hand is the worlds first prosthetic that promises to
restore movement to a paralyzed limb. The $50,000 implant was developed over
25 years of research at Case Western Reserve University and is being brought
to market by NeuroControl Corp. (Cleveland, Ohio), a company formed by the
inventors of the implant. 

The components of the Freehand device are: 

1. A shoulder position sensor that translates small shoulder movements into a
   control signal 

2. An external controller (usually located on a wheelchair) that receives the
   control signals and processes the information into radio waves to power
   and control the implant through a transmission coil 

3. A transmission coil worn over the implanted stimulator 

4. An implanted pacemaker-sized stimulator that sends electrical stimulation
   to 8 electrodes 

5. The electrodes that stimulate the muscles to contract, providing a
   functional hand grasp. 


Prosthetic Hand Promises Full Digital Movement 

The first prosthetic hand that will allow amputees to move the fingers
independently has been demonstrated at Rutgers University and could be ready
for production in a year. According to Carey Glass, a prosthesis consultant
on the project and president of CC. Medical Inc. (New Brunswick, NJ), "We can
start to think about wrist usage, elbow, even shoulder usage for people who
have lost an entire arm." One amputee has so mastered the device that he can
play a keyboard instrument with it. 

Conventional prosthetic hands have a metal claw or a soft-plastic hand with a
thumb and four fingers, but only the thumb and first two fingers move.
Moreover, their movement is limited to opening and closing at the same time. 

The prototype prosthetic at present operates only, the thumb, middle finger,
and little finger, future models are expected to work all five digits. The
system consists of the artificial hand; a silicon sleeve that is custom
fitted over the lower arm; three sensors inside the sleeve; and wiring from
the sensors to a computer and on down to the hand. Each sensor detects the
motion of one tendon that would normally move a particular finger, and the
computer then relays signals to that finger. 


Visual Implant Might Restore Sight to the Blind 

An implantable visual prosthesis being investigated at the Illinois Institute
of Technology may eventually restore a version of eyesight to the blind. The
research team is headed by Philip Troyk, associate professor of electrical
and computer engineering. 

The implants would be used to electronically stimulate a persons visual
cortex, that part of the brain responsible for processing and analyzing
light. The researchers are developing both the electronics and the hermetic
packaging for the 1 in. long by 1 in. high by 1/4 in. long device. 

The unit consists of four ceramic submodules, each containing custom ICs
controlling 64 channels, for a total of 256 channels. The hermetically sealed
device would be placed under the skin of a patients skull; wires from the
device would be inserted into the brain. A coil of wire worn on the patients
head would both power and communicate with the device. After converting the
original image to electronic form, the data would be transmitted to the
visual cortex and the patient would see the images as points of light. The
researchers hope that the plasticity of the brain will, over time, make sense
of the information and allow patients to see areas of gray and whole images,
not just points of light. 

The device may be ready for implantation within five years. The research is
being supported by a three-year, $1 million grant from the National
Institutes of Healths Neuroprosthesis Program.

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Implant Offers Sight to the Blind

From: R&D Magazine - October, 1998, page 122

Philip Troyk and his research team at the Illinois Institute of Technology,
Chicago (312/567-6902), are developing a visual prosthesis which may enable
blind people to visualize their surroundings. The implantable device
electronically stimulates the brain's visual cortex so that it converts
images into understandable electronic data. 

Patients using the device will first see only points of light, but
researchers believe they will learn to create whole images from the patterns.
The technology may provide blind patients with enough visual informatgion to
work on computers. 

The devices are implanted in the patients' skulls and connected to their
brains with wires. A coil of wire on the patient's head would serve to both
power and communicate with the device. 

Composed of four ceramic submodules containing integrated circuits, each
measuring 2.5 cm x 2.5 cm x 0.6 cm. Researchers believe that they will be
able to deliver a working device in three years. The first of these
prostheses may be implanted in patients within five years.


