Auditory-evoked brain stem response in patients with tumors in the internal auditory meatus

Abstract

Effects of pathologies in the internal auditory meatus on the auditory-evoked brain stem response (BSR) were assessed in two patients with tumors. In a patient with the facial neurimona, wave I of the BSR was recorded, alone. In a patient with acoustic neurinoma, the intervals between wave I latency and wave V latency were markedly delayed compared to those of the normal.
In order to clarify the interpretation of the results, the effects of middle and inner ear pathologies on the BSR were assessed in four patients with conductive and sensory hearing losses. In these patients the disappearance of the waveform of the BSR was not observed and the intervals between wave I latency and wave V latency fell within the normal range.
The data were interpreted as showing that the disappearance of certain BSR components, especially those following wave II, as well as an increase in the difference between wave I and wave V latencies can be used as indices of pathology of the internal auditory meatus.