Brainstem auditory response findings in late preterm infants in neonatal intensive care unit

Aim: To examine brainstem auditory function at term in late preterm infants admitted to neonatal intensive care unit (NICU). Methods: Fifty-two preterm infants, born at 33-36 week gestation, were recruited in an NICU and were studied at term using brainstem auditory evoked response (BAER). Results: Compared with normal term infants, BAER wave V latency in the NICU preterm infants was increased at 51 and 91/sec (p < 0.05, 0.05). Intervals of III-V and I-V were increased at all 21, 51 and 91/sec clicks (p < 0.05-0.01), which was more significant at higher than lower rates. Interval ratio of III-V/I-III was increased significantly at 51 and 91/sec (p < 0.05 and 0.01). Wave I and III latencies and I-III interval did not differ significantly from normal controls at any click rates. All amplitudes of waves I, III and V amplitude tended to be reduced at higher rates, while wave I amplitude was reduced significantly at 91/sec clicks. Conclusion: There were BAER abnormalities in the NICU late preterm infants, suggesting compromised brainstem auditory function. Compared with a basically normal BAER in low-risk late preterm infants previously reported, the abnormalities suggest that perinatal problems or complications adversely affect the late preterm auditory brainstem.