Maximum length sequence BAER at term in low-risk babies born at 30–32 week gestation

Thirty babies born at 30–32 week gestation without any major perinatal problems were studied at term with brainstem auditory evoked response (BAER) to detect any abnormalities in central auditory function in low-risk very preterm babies. The BAER was recorded and analyzed at 37–42 week postconceptional age using maximum length sequence technique (MLS). The data obtained were compared with those of 38 normal term controls. Wave I and III latencies in the very preterm babies did not show any significant differences from the controls at all repetition rates of click stimuli used (91–910 s−1). Wave V latency and I–V interpeak interval tended to increase at all click rates, and differed significantly from the controls at the highest rate 910 s−1 (P<0.05). Both III–V interval and III–V/I–III interval ratio increased significantly at all click rates, particularly at 455 and 910 s−1 (P<0.05–0.001). On the other hand, I–III interval tended to decrease. None of wave I, III and V amplitudes showed any abnormalities. Neither did V/I nor V/III amplitude ratios. These results suggest that development of the central auditory system is slightly delayed, which can be shown by MLS BAER at very high rate-stimulation, in low-risk very preterm babies.