Very low birthweight (VLBW) infants who had prolonged oxygen dependence due to chronic respiratory problems, typically neonatal chronic lung disease (CLD), are at high risk of neurodevelopmental impairment. To assess the effect of CLD on neonatal auditory function we studied brainstem auditory evoked response (BAER) in VLBW infants who suffered CLD but no other major perinatal complications or problems. At 37-42 week postconceptional age, the latencies of waves I, III and V in CLD infants were all significantly longer than in normal term infants (all p<0.001). The differences between CLD infants and the term controls were greater for the later waves than for the earlier waves. Abnormally prolonged wave latency (>2.5 SD of the mean measurement) was seen in 7 (21.2%) CLD infants for wave I, suggesting peripheral auditory impairment, 8 (24.2%) for wave III and 14 (42.4%) for wave V. I-V interval in CLD infants was significantly longer than in the term controls (p<0.001). Seven (21.2%) infants had abnormally prolonged I-V interval, suggesting brainstem or central auditory impairment. Of these infants, 2 had both prolonged wave latencies and prolonged I-V interval, suggesting both peripheral and central auditory impairment. Similar abnormalities were found in CLD infants when compared with the BAER in birthweight- and age-matched healthy VLBW infants without CLD.
Conclusion: Neonatal auditory function is impaired, both peripherally and centrally, at term age in VLBW infants who suffer neonatal CLD.