Postnatal functional status of the brainstem auditory pathway in term infants after perinatal hypoxia-ischemia.

OBJECTIVES: To examine postnatal changes in the impaired brainstem auditory pathway in term infants after perinatal hypoxia-ischemia (HI).

METHODS: Brainstem auditory evoked response (BAER) was studied at 2-4 months of age in term infants who suffered perinatal HI. The BAER data obtained at various click rates in these infants were compared with those in age-matched normal term controls to detect any abnormalities.

RESULTS: The infants after HI showed a slight elevation in BAER threshold. Four (9.8%) infants had threshold elevation. At 21/s clicks, there was a slight decrease in wave I latency, and a slight increase in wave III and V latencies. However, the I-V and I-III intervals in these infants were significantly increased ( p  < .05 and .05), whereas III-V interval was slightly increased. At higher click rates of 51 and 91/s, all BAER variables showed similar changes, with only small variations. An abnormal increase in the I-V and/or I-III intervals was seen in 4 (9.8%) infants, who were not associated with BAER threshold elevation.

CONCLUSIONS: At 2-4 months of age, around 20% of the infants after perinatal HI showed a moderate degree of either peripheral or central impairment of the brainstem auditor pathway. Monitoring postnatal changes could provide valuable information for postnatal care of infants after perinatal HI.