Auditory brainstem responses in neonatal hyperbilirubinemia and effect of therapy

Objectives; To determine the effect of neonatal hyperbilirubinemia on auditory brainstem responses (ABRs) and evaluate ABR responses to lowering of bilirubin levels.

prospective case control trial

tertiary referral center.

60 neonates (40 cases & 20 controls). Term appropriate for date(AFD) neonates with uncomplicated birth history and bilirubin level of ≥ 13 mg/dL were included as cases, those with bilirubin value of < 13 mg/dL were taken as controls.Interventions; First BERA examination was carried out within 24 hrs of the diagnosis of hyperbilirubinemia and repeat examination was done when total serum bilirubin came down to < 13 mg/dL with treatment. Comparisons were made between cases (before & after therapy) and controlResults; No abnormality in neonates with bilirubin < 18 mg/dL. Abnormal ABRs were observed in 24(60%) of the 40 cases studied, with therapy it reverted back to normal in 15(62%). The commonest abnormality noted was prolonged latency of wave V(42.5%), followed by prolonged latency of wave III(35%) and wave I(22.5%). Prolonged latency of wave I was found in only those with bilirubin > 20mg/dL. Inter peak latency of wave IV (Brain stem conduction time) was prolonged in 8 cases; it reverted to normal in all cases. Prolonged inter peak latency of wave I-III was observed in 7 cases, of which it reverted to normal in 6. Absent waves reappeared in 4 out of 5 cases, but abnormal amplitude ratios reverted to normal in only one of the 7 cases in which it was abnormal.Conclusions; about 60% of term A FD neonates with serum bilirubin of > 18mg/dL will demonstrate ABR changes. Most of these changes revert to normal early after therapy, indicating need for aggressive therapy in this subgroup of neonates.