High-resolution CT scanning and auditory brain stem response in congenital aural atresia: patient selection and surgical correlation.

Thirty patients with congenital aural atresia underwent CT scanning and/or auditory brain stem response (ABR) testing in a 20-month period. Eighteen patients had unilateral atresia and 12 had bilateral atresia. Twelve patients subsequently had surgery for repair of their atresia. CT scanning was not electively done until the patient was at least 2 years of age, while ABR testing was often performed in the first few months of life. Nineteen patients had CT scanning and 27 had ABR testing. The CT technique was found to offer specific advantages not previously observed in other methods of radiographic evaluation: (1) the course of the facial nerve was more easily traced and (2) the presence (or absence) of a stapes was more easily noted. The ABR was measured for monaural air-conduction as well as mastoid-placement bone conduction click stimuli; simultaneous multielectrode two- or four-channel recordings were employed. With this measuring technique it was not only possible to enhance wave I detection but, more important, the laterality of ABR wave I could be noted.