Brainstem auditory evoked response sensitivity: comparison with other neurologic tests in the detection of retrocochlear lesions.
Brainstem auditory evoked response (BAER) tests were obtained in 3 patients with suspected retrocochlear lesions. Subsequently, CT scans and the surgical procedure demonstrated tumors of about the same size (2 cm) in the cerebellopontine angle. One was an VIIIth-nerve schwannoma, one a meningioma, and one a VIIth-nerve neuroma. BAER recordings were analyzed with results of other tests: conventional audiometry, stapedius reflex measurements and electronystagmography (ENG). A striking finding was a normal BAER in the patient with the VIIIth-nerve schwannoma. ENG recordings in this case showed ipsilateral impairment of optokinetic nystagmus. The BAER was abnormal in the other 2 patients. A consistent abnormality for the 3 patients was absence of stapedius reflex in the ear in question. This study disclosed the advantage of utilizing a battery of tests in the investigation of retrocochlear lesions. The ENG recordings should include evaluation of the vestibulo-oculomotor pathways.
Benitez
J T
JT
Division of Otoneurology, William Beaumont Hospital, Royal Oak, Mich.
Arsenault
M D
MD
D000158:Acoustic Impedance Tests; D000328:Adult; D001299:Audiometry; D002528:Cerebellar Neoplasms / Q000175:diagnosis*; D002530:Cerebellopontine Angle; D003390:Cranial Nerve Neoplasms / Q000175:diagnosis; D004584:Electronystagmography; D005072:Evoked Potentials, Auditory; D005154:Facial Nerve; D005260:Female; D006801:Humans; D008297:Male; D008579:Meningioma / Q000175:diagnosis; D008875:Middle Aged; D009463:Neuroma / Q000175:diagnosis; D009464:Neuroma, Acoustic / Q000175:diagnosis