Normal brainstem responses in moderately preterm infants

Aim: The aim of this study was to detect any differences in brainstem auditory evoked responses (BAERs) to different click rates between moderately preterm and term infants. Methods: BAER was recorded with 21-91/s clicks at term age (37-42 weeks postconceptional age) in 39 moderately preterm infants (gestation 33-36 weeks). The results were compared with 37 healthy term infants. Results: The latencies of waves I, III and V, and I-V interval in preterm infants were all similar to term infants at all click rates. The I-III interval decreased slightly and differed from term infants at 91/s (ANOVA, p < 0.05), while the III-V interval increased slightly. The III-V/I-III interval ratio increased slightly and differed from term infants at 91/s (p < 0.05). Wave amplitudes were similar in the two groups of infants, except an increase in wave V amplitude at 91/s in preterm infants (p < 0.05). No significant differences were found in BAER click rate-dependent changes between the two groups. Conclusion: No marked differences were found in BAER at any click rates at term age between moderately preterm and term infants, suggesting that moderately preterm birth does not have a marked effect on neonatal BAER. BAER normal data and criteria from term infants can generally be used for moderately preterm infants.