Serial electrophysiological study on two infants with acute facial palsy.

Two infants with acute unilateral facial palsy were examined serially as to the electrically and mechanically elicited blink reflex, photo-evoked eyelid microvibration and auditory brainstem response (ABR). The results indicated that in hemifacial palsy beside the affection of the facial nerve also central pathways in the brainstem were involved in the pathogenetic processes. In particular, a neurapraxic change of the facial nerve itself in one case played an important role in pathogenesis, while a wide spread involvement was observed in another case. The clinical recovery of a patient with a wide spread involvement was more prolonged. We suggest that serial determinations of blink reflexes and ABR are helpful in clarifying the underlying pathogenetic processes concerning the brainstem affection during facial nerve palsy.