ABR Screening of High‐Risk Infants: Effects of Ambient Noise in the Neonatal Nursery

Abstract

This investigation examined ABR waveforms obtained at five signal intensities (20, 30, 40, 60, and 80 dB nHL) for adults and at three signal intensities (20, 40, and 80 dB nHL) for infants. ABR recordings were obtained in a quiet condition and repeated for three different intensity levels (40, 50, and 60 dBA) of background noise characteristic of a neonatal intensive care unit. The subjects were ten adults and ten infants whose ABRs were judged normal when measured at 20 dB nHL in the quiet condition. Results indicated that high levels of ambient noise (up to 60 dBA) did not influence either absolute wave V or interwave latencies measured for stimulus intensities of 60 and 80 dB nHL. ABR waveforms obtained at stimulus intensities often used for screening (i.e., 20, 30 or 40 dB nHL), however, were substantially altered for some subjects as a function of increasing levels of ambient noise. This observation was most apparent for the infant population and has important implications for the design of infant ABR screening programs.