Auditory Brain Stem Responses in Patients with Acoustic Tumor and Other Cerebellopontine Angle Tumors

Abstract

Auditory brain stem responses in five patients with cerebellopontine angle tumor were studied and the results were compared between the acoustic tumor and other cerebellopontine angle tumors. In cases of acoustic tumor, all five waves were unable to record. In cases of other cerebellopontine angle tumors not originated from the acoustic nerve (meningioma and cholesteatoma), auditory brain stem responses showed only the initial wave I after the affected ear was stimulated. On the other hand, auditory brain stem responses showed only the initial three waves (I-III) after the not-affected ear was stimulated.
The wave I represents the response of the auditory nerve and the latter four waves are generated in the brain stem auditory system. The wave V of the not-affected ear is suspectedly influenced crossly from the lesion mainly in the inferior colliculus.