Health Team

System helps amputee patients better control artificial limbs

Posted February 11, 2009 5:42 p.m. EST
Updated March 9, 2009 5:12 p.m. EDT

For amputee patients who have some nerves reattached, better control of advanced prosthetics is possible.

Several months after losing both of his arms while working as an electrical lineman, Jesse Sullivan became the first person to have the experimental surgery.

“I didn't know what was going to happen, but I didn't have anything to lose,” Sullivan said.

Dr. Todd Kuiken, of the Rehabilitation Institute of Chicago, developed a technique to take arm nerves and “move them to different muscles in the residual limb or chest.”

The brain remembers to stimulate those nerves, which helps him to close a prosthetic hand.

Sullivan’s surgery helped pave the way for dozens of patients.

Now, researchers have found a new control system that allowed five targeted muscle reinnervation, or TMR, patients to complete 10 different elbow, wrist and hand motions quickly and consistently with a virtual arm on a computer screen.

The system helped three of those patients go on to successfully control very advanced prosthetic prototypes, even though they had had only limited training.

The study is published in the Journal of the American Medical Association.

Researchers developed a computer program to better read the signals that the reattached nerves send.

Patients can control – to a degree – the motion of their wrists and can do more hand-grasping patterns with their real prostheses, Kuiken said.

“There’s a whole lot more movement there than before – because now, when I go home, instead of just open/close, I practice all of these movements,” Sullivan said.

Researchers plan to refine the control system further and would like to eventually give people with amputations the ability to feel where there arm is as they move it.