RETHINKING THE USE OF AUDITORY BRAIN-STEM RESPONSE IN ACOUSTIC NEUROMA SCREENING

The ability of magnetic resonance imaging (MRI) to detect very small a coustic tumors has triggered many to rethink the use of auditory brain stem response (ABR) in the screening of acoustic tumors, To assess ABR accuracy, we conducted. a retrospective study of 388 surgically treat ed patients. Of these patients, 111 had complete databases including b oth preoperative MRIs and ABRs. The ABR was abnormal by wave V interau ral latency difference in 106 (95%) of the cases, Although our overall sensitivity was 95%, sensitivity varied according to tumor size, ABR was abnormal or absent for all tumors (100%) larger than 2 cm in diame ter, for 98% of tumors 1.1 to 2 cm in diameter, and for only 89% of tu mors less than or equal to 1 cm in diameter. Ramifications of this in the decision-making process are presented. Criteria for cut-off values are also discussed.