Auditory brain stem response and audiologic tests in idiopathic facial nerve paralysis.

Idiopathic facial nerve paralysis is believed by some to represent one aspect of a polyneuropathy. Conventional audiologic tests have not demonstrated involvement of the auditory portion of the eighth cranial nerve in this disorder. A case history is given of a patient with this disorder and an associated abnormal auditory brain stem response (ABR). Our study involved onetime evaluations of 17 patients with idiopathic facial nerve paralysis of varying durations. Each examination included clinical presentation and history, an audiogram, acoustic reflex, and ABR. Another patient had abnormal acoustic reflex test results ("unibox" pattern) suggestive of a brain stem lesion. On reexamination concurrent recovery of the paralysis and acoustic reflex was demonstrated. No auditory system disturbances secondary to the paralysis were detectable by ABR in this survey. The concurrent recovery of the "unibox" acoustic reflex and the facial paralysis suggests the association of a brain stem lesion with idiopathic facial nerve paralysis in this case.