Brainstem Auditory Response Findings in Very Preterm Babies in the Intensive Care Unit

Abstract

Background: There is a need to increase our understanding of whether there is compromised brainstem auditory function in very preterm babies in intensive care. Objectives: To evaluate brainstem auditory function in preterm babies born at 32 weeks of gestation or earlier in the intensive care unit to detect any abnormality and the prevalence of the abnormality. Methods: We analyzed the brainstem auditory evoked response (BAER) at term in 156 babies born at 32 weeks of gestation or earlier in an intensive care unit. The data were compared to those of normal term babies to detect any differences. Results: The threshold of BAER was elevated in babies born at 32 weeks of gestation or earlier. All BAER wave latencies were significantly increased. The I-V interpeak interval was also increased. The amplitudes of BAER components tended to be reduced. Twenty-five (16.0%) babies in the intensive care unit had a BAER threshold elevation (>20 dB normal hearing level), suggesting peripheral auditory dysfunction. Thirty-three (21.1%) had an increased I-V interval, and 3 (1.9%) had a decreased V/I amplitude ratio, suggesting central or brainstem auditory dysfunction. Some babies had more than one BAER abnormality. As a whole, 51 (32.7%) babies had BAER abnormalities. Conclusion: Very preterm babies in the intensive care unit are at a high risk for auditory dysfunction. At term, 1 in 3 of these babies has peripheral and/or central auditory dysfunction.