Identification of neonatal hearing impairment: Summary and recommendations

Objectives: This article summarizes the results of a multi-center study, "I dentification of Neonatal Hearing Impairment," sponsored by the National In stitutes of Health. The purpose of this study was to determine the performa nce characteristics of three measures of peripheral auditory system status, transient evoked otoacoustic emissions (TEOAEs), distortion product otoaco ustic emissions (DPOAEs), and auditory brain stem responses (ABR), applied in the neonatal period in predicting hearing status at 8 to 12 mo corrected age. Design: The design and implementation of this study are described in the fi rst two articles in this series. Seven institutions participated in this st udy; 7179 infants were evaluated. Graduates of the neonatal intensive care unit and well babies with one or more risk factors for hearing loss were ta rgeted for follow-up testing using visual reinforcement audiometry (VRA) at 8 to 12 mo corrected age. Neonatal test performance was evaluated using th e VRA data as the "gold standard." Results: The major results of the study are described in the nine articles preceding this summary article, TEOAEs in response to an 80 dB pSPL click, DPOAEs in response to L1 = 65 and L2 = 50 dB SPL and ABR in response to a 3 0 dB nHL click performed well as predictors of permanent hearing loss of 30 dB or greater at 8 to 12 mo corrected age, All measures were robust with r espect to infant state, test environment and infant medical status, No test performed perfectly. Conclusions: Based on the data from this study, the 1993 National Institute s of Health Consensus Conference-recommended protocol-an OAE test followed by an ABR test for those infants failing the OAE test-would result in low r eferral rate (96 to 98%). TEOAEs for 80 dB pSPL, ABR for 30 dB nHL and DPOA Es for L1 = 65 dB SPL and L2 = 50 dB SPL perform well in predicting hearing status based on the area under the relative operating characteristic curve , Accuracy for the OAE measurements are best when the speech awareness thre shold or the pure-tone average for 2.0 kHz and 4 kHz are used as the gold s tandard, ABR accuracy varies little as a function of the frequencies includ ed in the gold standard. In addition, 96% of those infants returning for VR A at 8 to 12 mo corrected age were able to provide reliable ear-specific be havioral thresholds using insert earphones and a rigorous psychophysical VR A protocol.