Incidence evaluation of SNHL in high risk neonates

Objective: to evaluate hearing in high-risk neonates to find the incidence of congenital and early acquired sensory-neural hearing loss. Study Design and Setting: The study was designed as a consecutive cases, hospital based study in a tertiary care hospital. Patients: The subjects were 70 normal born neonates and 70 high-risk neonates. The 70 neonates with various high risks included in the study had family history of deafness, prematurity, IUGR, asphyxia, perinatal infections, hyperbilirubinemia, neonatal sepsis, meaningitis, ototoxicity and fetal malformations. Interventions: The study was conducted over a period of two years from Sep 2000 to Aug 2002. BERA using Octavus neuro-otological computer and a main unit BERA module with integrated preamplifier was performed within first 28 days of life and at 6 months follow up. Results: 44 out of 140 neonates showed abnormalities on initial BERA testing. 28 ears out of 67 ears (44 neonates) had losses confirmed at repeat BERA. Wave V was considered to determine the threshold of hearing and was found to be consistently present in neonates and also the wave. Hyperbilirubinemia (18 cases) and prematurity (29 cases) were the most commonly observed. The cases of Hyperbilirubinemia showed raised thresholds, absolute latencies and Wave I abnormalities (suggesting affection of eighth nerve). In the cases of Prematurity, 8 ears showed raised threshold at follow up. Asphyxia was found in 5 cases and is known to affect the auditory nerve. Family history of deafness found in 3 cases showed X-linked inheritance in one case and autosmal recessive inheritance in the others. Perinatal Rubella was observed in two cases, which showed hearing loss. Congenital malformations were seen in 7 cases (Waardenberg, Downs, Hydrocephalus and T-O Fistula). Neonatal Sepsis was observed in 3 cases and is known to affect the eighth nerve. IUGR was observed in 3 cases, two had normal hearing while one had no waveforms. Conclusion: BERA should be used as a screening tool to test the auditory function in all high-risk neonates.