DISTORTION-PRODUCT AND CLICK-EVOKED OTOACOUSTIC EMISSIONS OF PRETERM AND FULL-TERM INFANTS

Full-term and preterm infants were evaluated with click-evoked and dis tortion-product otoacoustic emissions (CEOEs and DPOEs). The CEOEs and DPOEs recorded from each individual ear were analyzed by calculating the root-mean-square levels within half-octave bands. The fail criteri on of the OE tests was that the half-octave RMS DPOE or CEOE levels of an ear under test were below the 10th percentile of full-term newborn s in two or more bands. The DPOE data were collected from 118 ears of 61 premature babies; 80 (68%) ears passed the DPOE test, 30 (25%) ears without middle ear effusions failed the test, and 8 (7%) ears with ef fusions also failed. The CEOE data were collected from 128 ears of 65 premature babies; 102 (80%) ears passed the CEOE test, 18 (14%) ears w ithout middle ear effusions failed the test, and 8 (6%) ears with effu sions also failed. In 23 of 80 ears (29%) that passed the DPOE test an d in 23 of 102 ears (23%) that passed the CEOE test, RMS OE levels of preterm infants were above the 90th percentile of full-term newborns. The analyses of the combined DPOE and CEOE data obtained from a group of 25 ears of full-term newborns and from a group of 72 ears of preter m babies showed statistically significant correlations between the DPO E and CEOE root-mean-square levels in each of the half-octave bands in the 1.4 to 4 kHz region. For 42 preterm infants tested with auditory brain stem response (ABR), specificity was 86% for CEOE and 74% for DP OE. All infants who failed the ABR also failed OE tests. To the best o f our knowledge, this study is the first using combined DPOEs, CEOEs, and ABRs for preterm babies. It showed the feasibility of DPOEs and CE OEs for this population.