Electrodiagnostic study in delayed facial palsy after closed head injury.

The time course of electrical reactions in this condition varied much from that after section of the facial nerve or after Bell's palsy. It was at least a week before denervation could be suspected in the latter conditions by electrodiagnostic methods. In post-traumatic delayed facial palsy we have demonstrated electrical reactions showing denervation at the time of palsy or even a few days before, and this is probably related to its pathogenesis. Denervation occurred in 82% of cases which is about double the incidence in Bell's palsy.