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.