Impaired neural conduction in the auditory brainstem of high-risk very preterm infants.

OBJECTIVE

To test the hypothesis that neural conduction in the auditory brainstem is impaired in high-risk very preterm infants.

METHODS

Eighty-two very preterm infants (gestation 28-32 weeks) with various perinatal problems or complications were studied at term using maximum length sequence (MLS) brainstem auditory evoked response (BAER) with click rates 91-910/s. The data were compared with those in 31 age-matched low-risk very preterm infants and 44 normal gestation (term) infants.

RESULTS

High-risk very preterm infants showed a general increase in MLS BAER wave latencies and interpeak intervals. Wave V latency, and III-V and I-V intervals in high-risk very preterm infants were significantly longer than in normal term infants at all click rates, particularly higher rates. I-III interval was significantly longer, and III-V/I-III interval ratio was significantly greater at higher rates. These latency and intervals in high-risk very preterm infants were also longer, though relatively less significantly, than in low-risk very preterm infants. Click rate-related changes in major MLS BAER variables in high-risk infants were more significant than in the two groups of controls.

CONCLUSIONS

There were major abnormalities in MLS BAER variables that mainly reflect central neural conduction in high-risk very preterm infants. The abnormalities were relatively less significant when compared with low-risk very preterm infants than with normal term infants.

SIGNIFICANCE

Neural conduction in the auditory brainstem, mainly the more central regions, is impaired in high-risk very preterm infants. The impairment is largely attributed to the associated perinatal problems, and partially related to very preterm birth.