SENSITIVITY OF AUDITORY BRAIN-STEM RESPONSE IN ACOUSTIC NEUROMA SCREENING

Auditory brainstem response (ABR) is the reference screening technique for acoustic neuromas, but because of a few false negatives and the i ncreasing performance of magnetic resonance imaging (MRI), its role as the standard method has been questioned. We assessed sensitivity of s creening tests in 89 patients with surgically proc en acoustic neuroma s. Sensitivity of ABR was 92%: 94% for extracanalicular neuromas and 7 7% for intracanalicular neuromas. For stapedius reflex (SR), sensitivi ty was 84% and for caloric vestibular response (CVR) 86%. The combined sensitivity of ABR + SR was 97% and of ABR + RS + CVR 98%. For false negatives, the greatest diameter including the intracanalicular portio n was always less than 18 mm, with a mean of 15 mm, and none of these tumours reached the brainstem. For patients with unilateral cochleo-ve stibular deficit, we propose ABR and SR as first-line screening tests. These tests are repeated at 6 months and at 1 year in the case of nor mal results. MRI is ordered for patients whose auditory threshold is t oo low and for those whose ABR or SR results favour retrocochlear dise ase.