Averaged Electroencephalic Audiometry in Infants

Abstract

Normal, preterm, and high-risk infants were tested at one, three, six, and 12 months of age using AEA. Few responded at 20 or 0 dB HL at any age. At one month, the lowest responses observed for the normal group averaged 43 dB HL, in contrast to an average of 59 dB HL for infants in the preterm and high-risk groups. At three months, the majority of infants in the normal and preterm categories yielded their lowest response at 40 dB HL. In contrast, infants in the high-risk group failed to yield the majority of their responses below 60 dB HL until age six months. Behavioral problems encountered in many of the infants at 12 months made it necessary to terminate testing prematurely. We do not know whether the inability to obtain responses at low hearing levels is due to procedural problems entirely or in part to immature neurological development beyond the peripheral auditory process. Infants could be prepared for testing easily at one and three months of age. In contrast, older subjects offered considerable resistance and were especially annoyed when conventional recording procedures necessitated that their movement be restricted. In this regard, telemetry was found to be most helpful since the coupling of the transmitter and receiver was by an FM radio frequency and not by wires as in conventional recording. However, movement artifact during testing was a significant problem regardless of the recording method employed.