Prospective Evaluation of Hearing Status in Neonatal Hyperbilirubinemia

Elevated bilirubin levels in neonates are commonly seen both physiologically and in pathological conditions. There are few articles describing the effects of elevated bilirubin levels on the auditory system. The objectives of this paper was to study the prevalence of hearing impairment in neonates with hyperbilirubinemia and assess outcome/reversibility of hearing impairment in these neonates with follow-up hearing evaluation. This was a prospective single centre, case control study. Cases: neonates, total bilirubin levels >15 mg/dl. Controls: <15 mg/dl. Exclusion criteria included neonates with neonatal hypoxia, intrauterine infections, sepsis or meningitis, infants with a family history of hearing loss, low birth weight, ototoxic medications, external and middle ear pathology. Otoacoustic emission testing (OAE) was done at birth. Neonates who fail OAE were advised follow up with Brainstem Evoked Response Audiometry (BERA) after 2 months. Neonates having abnormal BERA waves were called for follow up at 6 months. Out of 57 cases, 3 had failed OAE and had normal BERA waves on follow up at 2 months. Out of 60 controls, 5 had failed OAE and follow up BERA for 3 patients were normal and 2 babies were lost to follow up. No statistical significance in hearing impairment in hyperbilirubinemia v/s normal babies was noted. Elevated bilirubin levels in the absence of any other risk factors may not show significant changes in the hearing screening. Some effect owing to the p value close to being significant in cases has been noted. The same may not contribute to permanent hearing impairment as first OAE changes may be transient and seem to revert with age.