CORRELATION OF COMPOUND ACTION-POTENTIAL AND ELECTROMYOGRAPHY WITH FACIAL MUSCLE TENSION

Functional electric stimulation is a new method for dynamic rehabilita tion of paralyzed muscles. The output of such prosthetic devices needs to be modulated by some index of the muscle movement. In facial paral ysis a measure of the muscle contractions of the normal contralateral side seems to be an appropriate input. In the rabbit, we simultaneousl y measured the compound action potential of the buccal branch of the f acial nerve, the electromyogram of the zygomaticus major muscle, and t he muscle twitch tension through strain gauge. The compound action pot ential, electromyogram, and strain gauge each had a sigmoidal relation ship to stimulus intensity, The compound action potential peak-to-peak amplitude was found to have a linear correlation to the peak twitch t ension of the corresponding facial muscle. The electromyogram response , although more variable, also had a linear correlation with muscle co ntraction. The possibility of predicting the contraction of facial mus cles before they actually occur is discussed in the context of availab le and future functional electric rehabilitation models,