Audiometric study of the neonate: impedance audiometry. Behavioural responses and brain stem audiometry

The following clinical measurements of acoustic impedance were carried out successfully on 25 neonates. Average compliance was 0.48 cm3, with a range from 0.28 to 0.81 cm3. Tympanometry showed a high percentage of maximum compliance curves with positive pressures. In a notably high percentage, the stapedial reflex was combined with generalized body movements and was therefore considered a behavioural response. Behavioural responses of the child were also observed separately. Ipsilateral stimulation did not evoke a measurable stapedius reflex in any of the cases, but with contralateral stimulation some babies did show this reflex. The most intense behavioural responses occurred when white noise was used as the stimulus. Of the 25 children studied with impedance audiometry, 10 were evaluated audiologically by brain stem electric potentials. The latency of wave V was within the normal range in all the cases. Electric response audiometry could be a promising method for audiological evaluation of the neonate.