Closed Loop Microfabricated Facial Reanimation Device Coupling EMG-Driven Facial Nerve Stimulation with a Chronically Implanted Multichannel Cuff Electrode

Permanent facial paralysis and paresis (FP) results from damage to the facial nerve (FN), and is a debilitating condition with substantial functional and psychological consequences for the patient. Unfortunately, surgeons have few tools with which they can satisfactorily reanimate the face. Current strategies employ static (e.g., implantation of nonmuscular material in the face to aid in function/cosmesis) and dynamic options (e.g., gracilis myoneurovascular free tissue transfer) to partially restore volitional facial function and cosmesis. Here, we propose a novel neuroprosthetic approach for facial reanimation that utilizes electromyographic (EMG) input coupled to a chronically implanted multichannel cuff electrode (MCE) to restore instantaneous, volitional, and selective hemifacial movement in a feline model. To accomplish this goal, we developed a single-channel EMG-drive current source coupled with a chronically implanted MCE via a portable microprocessor board. Our results demonstrated a successful feasibility trial in which human EMG input resulted in FN stimulation with subsequent concentric contraction of discrete regions of a feline face.