Neural conduction impairment in the auditory brainstem and the prevalence in term babies in neonatal intensive care unit

•Term babies in neonatal intensive care unit (NICU) are at high risk of brain damage and neurological impairment.•The present study found that neural conduction in the auditory brainstem was impaired in NICU term babies, which occurred in one-third babies.•NICU term babies are at risk of the impairment and the high rates in maximum length sequence brainstem auditory evoked response enhance early detection of the impairment.

ObjectiveTo detect neural conduction abnormality in the auditory brainstem in term babies in the neonatal intensive care unit (NICU), determine prevalence of the abnormality, and assess if maximum length sequence (MLS) technique improves early detection of the abnormality.MethodsOne hundred and six term babies were recruited, and studied by recording and analysing MLS brainstem auditory evoked response (BAER). Interpeak intervals were analysed in detail, which were then compared with those in normal term babies.ResultsWave V latency and I-V and III-V intervals in MLS BAER were increased in the NICU term babies at all click rates 91-910/s, particularly at 455 and 910/s (p < 0.05-0.001). No major abnormalities were found in wave I and III latencies and I-III interval. The abnormal increase in I-V and III-V intervals were seen in significantly more cases at 455 and 910/s in MLS BAER than at 21/s in conventional BAER (X2 = 10.92-13.88, all p < 0.01). As a whole, 38 (35.8%) of the NICU babies had abnormal III-V and/or I-V intervals in MLS BAER, which was significantly more than 13 (12.2%) in conventional BAER (X2 = 16.14, p < 0.01).ConclusionThere is neural conduction impairment in the auditory brainstem in NICU term babies, which occurs in one-third of these babies.SignificanceTerm babies in NICU are at risk of neural conduction impairment in the auditory brainstem. High click rates in MLS BAER enhance early detection of the impairment.