Explains synkinetic movement following facial palsy, and crocodile tears and gustatory lacrimation. But no history of facial weakness. Irritation of sensory portion causes direct stimulation of motor segment. Ephaptic contact may depolarize axons orthodromically or antidromically. Mass effort of polarity changes in areas where decreased resistance lowers the firing threshold in damaged or ischemic nerves.
Damaged area excites axons antidromic impulses which activate facial nuclei motorneurons.
Anticonvulsants are not useful. Clinical Features 1. Involuntary bursts of tonic or clonic movements of the facial muscles. Mean age 45 years. Most frequently occurs first in the eyelids.