External and middle ear effects on infant hearing screening test results.

This study investigated the relationship between external and middle ear factors and hearing screening results by automated auditory brain stem response (ABR) and transient-evoked otoacoustic emissions (EOAEs). The ears of 200 healthy newborns aged 5 to 48 hours underwent screening by ABR and EOAE, followed by otoscopic examination. The pass rates for ABR and EOAE were 91% and 58.5%, respectively. On otoscopic examination, 28% (112/400) ears had occluding vernix obscuring the view of the tympanic membrane. Cleaning of vernix was successfully performed in all but 2 ears that had occluding vernix. Cleaning of vernix significantly increased the pass rates of all 400 ears for ABR and EOAE to 96% and 69%. Decreased tympanic membrane mobility was found in 22.7% (90/396) of ears that were evaluated otoscopically. Decreased tympanic membrane mobility had a significant effect on EOAE screening; only 33.4% of ears passed EOAE testing. Decreased tympanic membrane mobility did not significantly affect pass rates for ABR screening; 95% of these ears passed the automated ABR screen. Implications for newborn hearing screening are discussed.