False-negative brainstem auditory evoked potential recordings in a case of multiple acoustic neuroma.

A case history is reported to demonstrate that electrophysiological testing (brainstem auditory evoked potentials, BAEP and stapedius reflex) may fail in the search for cerebello-pontine angle tumours. The clinical history began with repeated episodes indicating a disorder of the vestibular system. Repeated testing of BAEP exhibited normal curves before and after surgery on the right side. This case serves as a reminder that normal BAEP do not necessarily exclude the presence of an acoustic neuroma developing in the immediate vicinity of the vestibular nerve.