Auditory-evoked brain-stem responses and auditory disorders in patients with Bell's palsy.

Out of 121 patients examined with acute unilateral facial paralysis, 93 were determined to have idiopathic facial palsy (Bell's palsy). The examination included pure-tone and speech audiometry, stapedial reflex recordings, temporal bone radiography and auditory-evoked brain-stem response testing (ABR). If a retrocochlear lesion was suspected, computed tomography or magnetic resonance imaging was performed. Patients with sensorineural hearing loss affecting all frequencies were compared to one group with hearing loss affecting only high frequencies and to another group with ABR findings suggesting a cochlear lesion. No association could be made between the etiology of these pathological results and the concurrent facial paresis. Most of them were probably caused by unrelated disorders of the auditory system. In cases with prolonged inter-peak latencies representing brain-stem responses, abnormal ABRs could be caused by the same pathology as the paralysis. This might well suggest the presence of a neuropathy in both the central auditory system and the facial tracts.