Auditory brain-stem response and hearing threshold in cerebellopontine angle tumours

The auditory brain-stem responses (ABR) in 19 patients with confirmed cerebellopontine angle tumours are evaluated in relation to the hearing threshold as obtained by pure-tone audiometry. ABR pathological alterations, in terms of either absence or presence of components, appear to relate to the suprathreshold stimulus intensity and to match the changes which can be observed in subjects with normal hearing, when stimulated at the equivalent suprathreshold intensity. Of the diagnostic indexes considered (I-V interval, IT5, delta V), IT5 and delta V could be evaluated in the largest patient population. They may be used in combination to enhance their sensitivity in retrocochlear lesion detection.