Distal electrical stimulation produces facial nerve regenerative and anti-synkinetic effects comparable to proximal electrical stimulation

Abstract Several reports indicate that electrical stimulation (ES) promotes peripheral nerve regeneration, primarily when applied proximal to the site of injury. However, when considering its application in facial nerve palsy, which is most commonly of viral origin, the lesion is typically located within the temporal bone, rendering proximal stimulation challenging. Therefore, despite its therapeutic potential, ES has not been successfully translated into clinical treatment for facial nerve palsy. The present study investigated whether distal ES could achieve regenerative and anti-synkinetic effects comparable to those of proximal stimulation using a rat facial nerve crush model. The animals were divided into three groups: no stimulation, proximal ES, and distal ES. Functional recovery was assessed using the eye blink reflex and whisker movement, whereas synkinesis was evaluated using electromyography and retrograde labeling. Both proximal and distal ES significantly promoted functional recovery and reduced synkinesis compared to controls. Importantly, the effects of distal stimulation were comparable to those of proximal stimulation across all assessments. These findings suggest that stimulation applied at a site distal to the injury—which, unlike proximal stimulation, does not require surgical exposure of the lesion itself—can achieve regenerative and anti-synkinetic effects comparable to proximal stimulation. This proof-of-concept evidence, while not a direct demonstration of clinical efficacy, supports further preclinical evaluation of distal ES as a potential therapeutic strategy for facial nerve palsy.