Transient evoked otoacoustic emissions (TEOAEs) in new-borns: normative data

Objective: Early diagnosis and rehabilitation of congenital hearing loss ar e mandatory in order to achieve a satisfactory linguistic and cognitive dev elopment. A universal hearing screening in order to identify congenital hea ring losses before 3 months of age is required. Methods: TEOAEs are an easy to perform, short lasting, not invasive and low-cost test with a high sens itivity. 320 at term new-borns (640 ears) without any risk factor for heari ng loss underwent TEOAEs. The new-borns were screened 3 days after birth. T hose who failed the first test were retested when possible before the disch arge from the hospital. ABR was performed 3 months later in cases who faile d TEOAE. Results: The median TEOAE sampling time was 98 s, the median test duration was 14 min. The mean stimulus amplitude was 80 dB peSPL in the lef t ear and 81 dB peSPL in the right ear, noise levels within the external me atus during sampling were 44 dB SPL on the right ear and 43 dB SPL on the l eft one, noise contained within the response (A-B difference) was 8.65 dB S PL in the left ear and 8.74 dB SPL in the right ear, mean TEOAEs amplitudes were 21.49 dB SPL and 21.78 dB SPL in the right and left ear respectively, the mean lower and upper limit of the spectrum being 678 and 5720 Hz. Acco rding to these criteria 494/640 ears (77.2%) passed the test at the first r ecording, while TEOAEs resulted to be absent in 146/640 ears (22.8%). A ret est was performed successfully before the discharge from the Hospital in 30 /640 ears (4.7%). An ABR recording within the third month of life was sched uled as out-patient in the 58 new-borns (116 ears, 18.2%) who failed the te st. 18 of them (36 ears, 5.6%) did not complete the program, 19 new-borns ( 38 ears, 11.8%) showed a normal ABR, while two new-borns (four ears, 0.6%) failed ABR after 3 months. A second ABR performed after 6 months was normal . Conclusions: TEOAEs recording seems at now the test of choice for a unive rsal hearing screening. However, a greater standardization of criteria both in performing the test and in evaluating the results is needed. (C) 1999 E lsevier Science Ireland Ltd. All rights reserved.