Impedance Audiometry in Neonates

Abstract

Acoustic impedance measurements were performed on 400 ears of 188 normal neonates using the 1722 middle ear analyzer (Grason-Stadler) with a 220-Hz probe frequency. Most of the data were obtained while the neonates were asleep without anesthesia.
The measurement could not be accomplished in only thirteen percent of all the ears. Sixty-five percent of the tympanograms showed an atypical AD type configuration, namely a large, smooth notched curve without a steep peak. Sixteen percent showed a double peak, and this percentage became less after the second week of life. The types of tympanograms were not correlated with the birth weight of the neonates. A clear stapedial reflex was obtained in only three percent.