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INNOVATION FOR INDEPENDENCE
ISSUE 103 JUNE/JULY 2015 £6.95
Device may allow prosthetic hands to feel sensations By Nicola Hyde RESEARCHERS have developed a novel device that may allow individuals to feel hot, cold and the sense of touch through a prosthetic device.
The ulnar nerve, one of three main nerves in the forearm, is the largest nerve in the body unprotected by muscle or bone and is connected to the ring finger and pinkie finger on the hand.
A team of engineers and researchers at Washington University in St. Louis is working to change that so those with upper limb prosthetics can feel hot and cold and the sense of touch through their prosthetic hands.
It’s the nerve that is stimulated when a hit to the elbow triggers the “funny bone.”
Daniel Moran, PhD, professor of biomedical engineering in the School of Engineering & Applied Science and of neurobiology has received a three-year, nearly $1.9million grant from the Defense Advanced Research Projects Agency (DARPA) to test the device that would stimulate the nerves in the upper arm and forearm. If it works, upper-limb amputees who use motorised prosthetic devices would be able to feel various sensations through the prosthetic, which would send sensory signals to the brain. Daniel, whose expertise is in motor neurophysiology and brain-computer interfaces, and his team have developed an electrode designed to stimulate sensory nerve cells in the ulnar and median nerves in the arms.
The median nerve in the upper arm and shoulder is connected to the other fingers on the hand, so together, the two nerves control movement and sensations including touch, pressure, vibration, heat, cold and pain in all of the fingers. People using arm prosthetics have to rely on their vision to use them properly, Moran said. To pick up a cup of coffee, they have to be able to see the cup, place the fingers of the prosthesis around it and lift it. They are unable to feel whether the cup is in their hand, if the cup is hot or cold, or if they are about to drop it. By enabling the ability to feel, users will have more control over the prosthesis. The team developed a macro-sieve peripheral nerve interface designed to stimulate regeneration of the ulnar and median nerves to transmit information back into the central nervous system.
Limbcare has been announced as a winner of the Queens Award for voluntary service. The charity, which supports amputees and their families, was founded five years ago by quad amputee Ray Edwards MBE (pictured above). As a quad amputee Ray is aware of the emotional and physical challenges facing new amputees and their families. He said: “Servicemen and women get great support from the military and the wonderful Help for Heroes if they have a limb amputated – but civilians have no such support. Limbcare helps to fill that gap by offering, among other things, emotional support and advice. In particular Limbcare is there to let amputees and their families know they are not alone. For many amputees it’s the knowledge that someone else has ‘been there too’ which is the most important.”