Auditory brainstem evoked potentials in sudden deafness.

Auditory Brainstem Evoked Potentials (ABEP) were recorded from 53 adult subjects suffering from sudden deafness at the time of examination. The onset of sudden deafness was up to three years prior to the study. ABEP were recorded in response to 75 dBHL clicks presented at rates of 10/sec and 40/sec. ABEP peak latencies as well as interpeak latency differences, and also the effect of increasing stimulus rate, were determined for each patient and compared with the clinical symptoms. The psychoacoustic and ABEP detection thresholds were also compared. A highly significant correlation was observed between ABEP detection threshold and the psychoacoustically determined hearing threshold, and the differences between them were found to be insignificant. The results of this study indicate a central component in sudden deafness. This impairment manifests itself in abnormal effects of increasing stimulus rate on ABEP, and may be related to reduced central synaptic efficacy.