Comparison of distortion product otoacoustic emissions with auditory brain-stem response for clinical use in neonatal intensive care unit

Objectives: This study compares the clinical usefulness of distortion produ ct otoacoustic emissions (DPOAEs) with the auditory brainstem response (ABR ) for neonates in the neonatal intensive care unit for the evaluation of he aring impairment. Methods: Both DPOAEs and ABR were performed on 36 neonates (67 ears) on the same day. We defined neonates as having normal hearing when the thresholds of wave V of ABR were less than or equal to 45 dB hearing level. Results: (1) We could not obtain DPOAEs at f2 = 977 Hz in neonates with nor mal hearing because of high noise floors. DPOAE recording time was 36 min s horter than that of ABR. (2) We defined as normal DPOAEs, the number of fre quencies which showed the DPgram-noise floor greater than or equal to 4 dB was greater than or equal to 4 at 6 f2 frequencies, from 1416 Hz to 7959 Hz . (3) Normal thresholds of ABR and normal DPOAEs showed the same percentage s, i.e. 68.7%, but the percentage of different results between ABR and DPOA Es was 6.0%. Conclusions: Our study indicates that DPOAEs represent a simple procedure, which can be easily performed in the NICU to obtain reliable results in hig h-risk neonates. Results obtained by DPOAEs were comparable to those obtain ed by the more complex procedure of ABR. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.