Auditory brainstem response in hyperbilirubinemic rat: Part I.

The effect of hyperbilirubinemia on the auditory brainstem response (ABR) of rats and its change by hyperosmolality were examined. The ABR wave I did not change significantly. In bilirubin-loaded rats, the latencies of wave II and IV were prolonged and the amplitudes decreased. Bilirubin injection damaged the central auditory pathway but the peripheral auditory pathway was spared. These ABR changes were reversible in the acute phase of hyperbilirubinemia. Mannitol administration hastened the appearance of the ABR peaks and the recovery of the changed ABR. This tendency was more remarkable in latency changes than in amplitude changes.