Electromyographic study relating to shoulder motion: control of shoulder joint by functional electrical stimulation.

The purpose of this study is to create the standard stimulation patterns of shoulder motion from electromyographic (EMG) data in 13 healthy human volunteers in order to control the movement of the paralyzed shoulder in quadriplegic and hemiplegic patients by functional electrical stimulation (FES). Simultaneous EMG measurement was made at 24 points of 17 major muscles relating to shoulder motion. Since the number of the output channels in the portable FES apparatus is limited, 12 major muscles were selected from statistically processing these EMG data and stimulation patterns were created based on the EMG data of these muscles. Thus three standard stimulation patterns were created to move the shoulder, i.e., (i) 90° flexion to 90° horizontal abduction, (ii) 90° flexion to 20° horizontal adduction, and (iii) 90° abduction to 90° horizontal adduction. With the created stimulation patterns, the restoration of the shoulder motion in plegic patients was successful and it will be reported in the next paper.