Term neonates receiving intensive care at high risk of brainstem auditory impairment.

Functional integrity of the auditory brainstem was examined using maximum length sequence brainstem auditory evoked response in 72 term neonates who were receiving intensive care. Compared with normal term controls, the neonates receiving intensive care showed an increase in wave V latency and I to V and III to V interpeak intervals of the response. Wave V latency was significantly increased at very high click rates 455 and 910/s. I to V and III to V intervals were significantly increased at all 91 to 910/s, particularly 455 and 910/s, while I to III intervals were slightly increased. III to V/I to III interval ratios were increased at 455 and 910/s clicks. The slopes of wave V latency-rate, I to V interval-rate, III to V interval-rate and III to V/I to III-interval-ratio-rate functions were significantly steeper than in normal controls. These abnormalities suggest that neonates receiving intensive care are at high risk of brainstem, mainly more central regions, auditory impairment. The MLS BAER abnormalities and brainstem auditory impairment might be the result of collective adverse effects, produced by more than one perinatal risk factor.