Auditory brainstem response. Sensory assessment by bone conduction masking.

Auditory brainstem response (ABR) thresholds to clicks were determined for 15 normal hearing adults and for four patients with conductive, sensorineural, or mixed hearing losses. Conductive losses were created in five of the normal hearing adult subjects for which threshold assessment was repeated. The response to a click at 5 dB above threshold was masked with a high-pass, bone-conducted noise. For both the patients and the normal subjects, subtracting 15 dB from the amount of noise required to mask this ABR response approximated sensory threshold. Tympanometry was performed on all patients, except one exhibiting unilateral congenital atresia, to confirm middle ear status.