Audiologic evaluation of neonates with severe hyperbilirubinemia using transiently evoked otoacoustic emissions and auditory brainstem responses.

Abstract

To audiologically clarify the lesion site and to test the reliability of transiently evoked otoacoustic emissions (TEOAEs) in hearing screening of hyperbilirubinemic neonates. Eleven neonates with severe hyperbilirubinemia who had exchange transfusion in the neonatal intensive care unit of an academic hospital over a 3-year period were included in this study. They were tested with auditory brainstem response (ABR) and TEOAEs after exchange transfusion during hospitalization or at an immediate follow-up visit after discharge. Follow-up ABR tests were performed when infants showed significant hearing loss. ABR and TEOAE tests were performed on the 11 neonates with severe hyperbilirubinemia after exchange transfusion. Follow-up ABR tests were carried out in 3-month intervals in the four neonates who showed abnormal or no response on initial ABR. Four neonates showed abnormal or no response and the other seven demonstrated normal response in ABR. All 11 neonates passed TEOAEs. Two neonates showed improvement in auditory function at 3- or 6-month follow-up ABR. The results of this study indicate that the site of lesion in hearing loss caused by hyperbilirubinemia may be at the retrocochlear location while the cochlea remains intact. TEOAEs may have limitations in evaluation of hearing in the neonates with hyperbilirubinemia.