Brain-stem auditory evoked potentials in at-risk infants and follow up assessment in Sri Lanka

Abstract

Background: The effect of various risk factors on hearing impairment (HI) in infants has not been studied extensively in Sri Lanka until now. Objectives:To determine the influence of perinatal risk factors on the brainstem auditory evoked potentials (BAEP) in infants in Sri Lanka and to assess the follow up BAEP waveforms of infants with elevated hearing thresholds after 6 months. Method:We recorded BAEP waveforms of 100 eligible at-risk infants using auditory click stimuli. Prematurity, prolonged neonatal intensive care unit (NICU) stay >5 days, very low birth weight (VLBW), hyperbilirubinaemia, ototoxic medications, mechanical ventilation, meningitis and sepsis were the perinatal risk factors considered. Risk factors of HI were determined using multiple logistic regression modeling. We did a follow up assessment after 6 months in 26 infants with elevated hearing thresholds and compared the data of the two assessments.Results: Prematurity (odds ratio: 3.08, 95% CI: 1.05-9.04, p=0.04) and prolonged NICU stay (odds ratio: 3.67, 95% CI: 1.00-13.49, p=0.05) were the significant risk factors for developing HI as indexed by increased BAEP threshold levels. Seventeen out of 26 infants attended the follow up study and five improved.