Auditory brain-stem evoked potentials in Bell's palsy.

In an attempt to assess objectively the integrity of the auditory pathways in patients suffering from Bell's palsy, an audiometric evaluation was performed and auditory brain-stem evoked potentials (ABEP) were obtained from 24 patients within the first week from the onset of facial weakness. Despite negative audiometric findings, significant ABEP abnormalities (greater than 2.5 SDs) were observed for 25% of the sample. In each case the ABEP deviation suggested prolonged brain-stem conduction time; for some patients the aberration was only apparent with an increased stimulus repetition rate. The ABEP measures were found to be independent of the side or severity of the paralysis, the acoustic reflex, or reported dysacusis. The ABEP was of no value in predicting recovery of facial muscle function. It is suggested that the facial paralysis may be only the overt manifestation of a generalized pathologic condition.