Objectives: To determine the sensitivity of auditory brainstem response (ABR) testing for detecting acoustic neuromas and to determine whether the test is less sensitive for detecting small tumors.
Design: Retrospective review of the medical charts of 58 patients with acoustic neuroma who had all of the data necessary for inclusion in the study.
Setting: University-affiliated referral practice of one neurotologist.
Patients: Patients with acoustic neuromas who had both ABR tracings and magnetic resonance imaging films available for review.
Main outcome measures: Positive ABR and negative ABR results correlated with tumor size.
Results: Tumor size ranged from 0.4 to 7 cm. The overall sensitivity of ABR in diagnosing acoustic neuromas was 90%. However, ABR was progressively less sensitive with decreasing tumor size. Only 7 (58%) of the 12 tumors 1 cm or smaller were detected by ABR.
Conclusion: Auditory brainstem response testing cannot be relied on for detection of small acoustic neuromas and should not be used as a criterion to determine whether magnetic resonance imaging should be performed when an acoustic neuroma is suspected clinically.