Doctors have long thought that microelectronics could bring movement to patients paralyzed by stroke. Often, the patient's muscles are in good condition: They just can't receive or respond to signals from the brain. With the right combination of sensors, microchips, and electrodes, doctors reasoned, many of these patients could be back on their feet.
The problem has been coordinating stimulation of several groups of muscles simultaneously. That's essential to induce complex movements such as clasping a glass of water. This month, researchers at Tohoku University and NEC San'ei Co.--a subsidiary of Japanese giant NEC Corp.--will start shipping a system constructed around a Zylog Z-80 microprocessor that can deliver electric impulses to 16 different muscles at once.
In contrast to earlier systems, which were heavy and clumsy to operate, the Japanese group has condensed the control unit into a waist pack slightly bigger than a Sony Walkman. The patient sends instructions to the microcomputer by blowing into tubes attached to a mouthpiece. The computer recognizes the desired motion, and sends out the necessary signals to a network of electrodes. For now, NEC is shipping samples only to a select group of Japanese hospitals. If the response is good, the company could begin commercial shipments this year, for prices under $10,000.