Bionic system helps paralyzed hands.

Tiny electrodes implanted inside the arm of a paralyzed man are helping him regain some function in his hand. The implants are part of a bionic system that is undergoing a clinical trial by Stanford University physicians at the Palo Alto (Calif.) Veterans Affairs Medical Center. Dennis Canoy, who had the system implanted in March, 1994, says the biggest change in his life so far is that he can eat dinner, watch television, and write a letter with minimal assistance for the first time in 10years. Canoy sustained a broken neck in a May, 1984, auto accident. The injury left him paralyzed from the top of the chest down, but still able to move his shoulders and elbows. Shoulder movement is crucial because they give the computer the command to move the hands. Researchers at other project centers have been working on a voice-activated system that would eliminate the need for shoulder movement, but it is far from becoming a usable alternative.

Rod Hentz, professor of functional restoration and chief of hand surgery at the Stanford School of Medicine, and his colleagues implanted a platinum electrode in each of seven muscles in Canoy's right wrist. When an electrical current is sent through to one of the electrodes, the associated muscle contracts. The wires of the electrodes tunnel through his arm and connect to a matchbook-sized box implanted in his upper right chest. Another wire from the box goes to an electrode in his neckline, near the collarbone--one of the few areas where Canoy still has feeling. The purpose of this electrode is to give him a little shock to tell him whether the system is on and working properly.

In addition to the...