Patients paralyzed by strokes or spinal cord lesions are now able to regain certain functions. Microcomputers are being perfected that stimulate certain programmed activities such as grasping and walking. Fine wire leads convey electrical impulse initiated by the microcomputer to either peripheral nerves or directly to the muscles responsible for the desired movement.

The program is initiated by the subtle movement of muscles not affected by the paralysis. Sensors connected to the microcomputer are attached to the skin overlying functional muscles and are able to detect electrical activity associated with movement of the underlying muscles. For example, a person with both legs paralyzed may have such a sensor attached to the abdomen. The abdominal muscles, normally involved in walking, are stimulated by descending tracts when walking is initiated by CNS centers. The resultant abdominal muscle activity is detected by the sensor, which activates the program that stimulates the appropriate sequence of muscles, and the paralyzed person walks. Similarly, a quadriplegic can initiate certain grasping actions by subtle movements of the shoulder, neck, or face, where specific sensors can be placed.

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