重心動揺検査と積分筋電図の相関について

抄録

Posturography (PG) and integrated electromyography (EMG) were recorded simultaneously and their inter-dependence was examined. Surface electrodes were placed on the skin over the triceps surae bilaterally because these muscles control the center of foot pressure to maintain stability in the standing position. Electro-myograms were integrated with a time constant of 0.1 sec. Two oscillations, one from PG and one from integrated oscillations of EMG, were correlated. As long as body sway was limited to a small area, the two waves showed no correlation. However, with larger body sway, the correlation was higher. Oscilations in the antero-posterior (A-P) direction showed the highest correlation of PG and EMG. On the other hand, when oscillations were in the right-left (R-L) direction the correlation of PG and EMG was lower. These findings indicate that A-P oscilla-tion and R-L oscillation are independent in PG in the standing position. The positive correlation between PG and EMG implies that the pivot of body sway is in the ankle joint. These findings support the theory that body sway oscillation resembles that of an inverted pendulum.