Electronic Reanimation of Facial Paralysis—A Feasibility Study

Abstract

We set out to adapt the concept of functional electrical stimulation to the reanimation of the paralyzed face. In the New Zealand white rabbit model we studied the strength-duration curves of both innervated and denervated facial muscles. We next studied the electromyographic signals corresponding to different strengths of contraction of innervated facial muscles. With Teflon-coated stainless steel electrodes implanted at opposite ends of the denervated muscle groups under study, bipolar stimulation yielded useful mimetic function that was modifiable by varying the voltage output and the rate of pulse generation. We demonstrated that an electronic circuit can indeed respond to the voltage generated within a functioning facial muscle, and then reproducibly trigger a corresponding graphic signal in synchrony with the mimetic function. The next step will be to adapt an electronic circuit that will deliver a predetermined electrical current to a denervated facial muscle in response to a determined generated voltage in the contralateral corresponding innervated facial muscle.