Abstract
Auditory brainstem response (ABR) testing has been a major tool in the diagnosis of neurootogenic diseases like the acoustic tumors, because of its high sensitivity. Several investigators have reported the sensitivity of ABR testing in the diagnosis of acoustic tumors as 90% or greater. Recently, with the availability of improved imaging modalities, some patients who had normal ABRs were diagnosed to have acoustic tumors. Some investigators have therefore reported that ABR had a much lower sensitivity than expected. To evaluate these reports, a series of 50 cases of (55ears) acoustic tumors who attended the out patient clinic at the Nippon Medical School were analyzed. The ABR abnormalities were classified into one of the following categories: 1. Partial wave disappearance. 2. Prolongation of the latency, wave I to V. 3. No response. I lears (20%) showed partial wave disappearance. 27ears (54%) showed prolongation of the interpeak latency, wave I to V. 16ears (30%) showed no response. Thus, all patients with acoustic tumors had abnormal ABRs in our series. Our results suggest that ABR testing when carried out by specialized hands is a valuable method in the screening of acoustic tumors.
