Evaluation of Auditory Brainstem Responses (ABR) in Healthy Term Infants with Elevated Bilirubin Levels Requiring Exchange Transfusion

Hyperbilirubinemia is a common neonatal abnormality. Severe hyperbilirubinemia is a risk factor for auditory system injury. Auditory brainstem responses (ABR) are important in early diagnosis of hearing impairments in healthy term infants with elevated bilirubin levels requiring exchange transfusion. During a two- year- period (2007 – 2009), in a prospective descriptive analytical study, in Tehran Milad Hospital, 64 (32 female, 32 male), healthy term (> 37 weeks) infants, who required treatment or were treated with phototherapy or received exchange transfusion for elevated bilirubin levels or jaundice, were studied. After obtaining a written consent from their parents, the infants were tested with auditory brain responses and results were analyzed using SPSS 16 software. No significant correlation was found between ABR and age, weight, bilirubin level or ABO blood group. Nineteen out of 64 infants received exchange transfusion. Three out of 19 infants (16%) exhibited abnormal ABR and 16 infants (84%) had normal ABR. There was no significant correlation between exchange transfusions and ABR (P>0.05). The results pointed out that 14% of the infants with elevated bilirubin who required exchange transfusion had abnormal ABR. This indicates that elevated bilirubin levels even without inducing kernicterus should be considered as risk factors for hearing impairments. Further studies are needed on how long these tests may remain abnormal.