Bell's palsy–associated blepharospasm relieved by aiding eyelid closure

Abstract

The efficacy of the blink reflex is maintained by adaptive control mechanisms. We describe a 39-year-old woman with the rare complication of blepharospasm-like symptoms appearing contralateral to an eyelid weakened by facial nerve palsy. The hyperexcitable blink reflex may be a maladaptive consequence of adaptive systems but was not accompanied by an expected increase in main sequence slope. Eyelid spasms were eliminated by the implantation of a gold weight to assist closure of the paretic eyelid. We suggest that aiding closure of the weak eyelid in this case caused a reduction in blink system excitability via the same compensatory mechanisms that initially produced the eyelid spasm. Data also suggest that blink-adaptive systems act via changes in reflex excitability and/or main sequence relationships, and that these may be regulated either synergistically or independent of one another.