BERA in Newborns with Hyperbilirubinemia

Abstract

BACKGROUND: Neonatal hyperbilirubinemia is a common problem seen in the newborn period, is usually mild and transient without long-lasting sequelae. Bilirubin induced neurologic damage may occur and auditory pathway is the most sensitive past to bilirubin toxicity. Auditory brainstem response (BERA) provides an electro physiologic means of assessing ascending auditory pathway and to localise the lesion. AIMS: To assess the effect of bilirubin toxicity on brainstem auditory pathway among neonates with hyperbilirubinemia using BERA and compare with control of normal newborns. MATERIAL AND METHODS: BERA was recorded in twenty five term newborns admitted to Tertiary care hospital, with hyperbilirubinemia at level exceeding exchange transfusion (mean bilirubin level 25.4+/- 4.66 mg/dl). They were compared with 25 term normal newborns without any risk factor for hearing impairment. The results were analysed by Gaussian test (Z), student unpaired ‘t’ test, chi square test and Mann-Whitney U test. RESULTS: At least one of waves I, III and V was absent in 8% of newborn with hyperbilirubinemia. There was statistically significant prolongation of mean latencies of waves III and V and mean I-V interwave latency in hyperbilirubinemia newborn compared to normal neonates . Auditory threshold was elevated in 6 out of 25 jaundiced newborn. Significant positive correlation between BERA abnormalities and bilirubin levels was found with respect to presence of waves I, III and V and auditory threshold. No significant positive correlation was found between bilirubin levels and BERA latencies. CONCLUSION: BERA abnormalities were noted in form of absence of waves I, III, V,prolongation of latency and interwave latencies and increased auditory threshold in newborns with hyperbilirubinemia as compared to normal neonates. BERA abnormality was also found to be transient and was normal in most of these patients during follow up.