Development of an EMG recording device from stimulation electrodes for functional electrical stimulation.

A device that records voluntary EMG from a pair of surface stimulation electrodes has been developed for functional electrical stimulation (FES). The device can apply to a small muscle on which it is difficult to locate both the stimulation electrodes and recording electrodes. The device utilizes photo-MOS relays to disconnect the stimulator when it is not active, to ground the electrodes after delivering the stimulation pulses, and to drop the gain of the EMG amplifier during the stimulus period. The device is able to detect the voluntary EMG of a small muscle from the stimulation electrodes for the EMG-controlled FES system.