AUDITORY BRAIN-STEM RESPONSE - A COMPARISON OF DIFFERENT INTERPRETATION STRATEGIES FOR DETECTION OF CEREBELLOPONTINE ANGLE TUMORS

In this retrospective study (111 tumor; 1370 non-tumor patients), the effectiveness of the auditory brainstem response for identifying cereb ellopontine angle tumors was studied using different criteria to inter pret the test. Individual ABR features were examined. The I-V was best (sensitivity = 82%; specificity = 97%) but present for only 44% of th e population I-III (sensitivity = 50%; specificity = 96%) and III-V (s ensitivity = 30%; specificity = 97%) were worst. Ninety-three percent of patients had V and ILDV, with good results (sensitivity = 74% and 8 1% respectively; specificity = 93% each). Three interpretation strateg ies were compared: (I)included the latencies of V, ILDV, I-V, III-V an d I-III and ILDI-V, (2) excluded III-V and I-III, (3) used I-V and ILD I-V when available; V and ILDV otherwise. When corrected for hearing l oss, strategy 3 provided significantly better specificity (91%) than s trategy 1 (87%), with no significant difference in sensitivity (92% an d 93%, respectively).