DISCUSSION
Unconjugated bilirubin crosses blood brain barrier and causes damage in
terms of hearing and neurodevelopmental. Indirect bilirubin, is strongly
neurotoxic for under developed neural system, especially when the
indirect bilirubin concentration exceeds the albumin binding capacity.
The phenomenon of deposited indirect bilirubin in basal ganglia as well
as in the vestibule- cochlear nuleus causes a neurological syndrome
called kernicterus as well as sensorineural hearing loss (SNHL). BERA
detects SNHL and aids in early diagnosis and management.
The present study found a significant association between peak serum bilirubin levels and BERA changes. The percentage of abnormal BERA in the present study (51.95%) was higher as compared to studies conducted by Agrawal et al[9] (23.3%) and Sharma et al[10] (22.5%). Saluja et al[11] found out that 6/13 (46.15%) had abnormal BERA \soutafter treatment. after phototherapy or exchange transfusion. The observation was similar to the present study in which 89.67% neonates who underwent exchange transfusion had abnormal BERA. Studies in Iran by Bardaranfar et al[12] and Okhravi et al[13] also showed a significant association between BERA and hyperbilirubinemia. Carlos et al[14] also found that the frequency of sensory neural hearing loss SNHL in children with a history of exchange transfusion treated at a 3rd level hospital in Mexico City was high (15%). P Shankar and Manjunath[15] found the incidence of hearing loss in NNH to be 8.6%. However, the studies, done by Chen et al[16] and Duman et al[17], were not in concordance with the present study. Table.3. summarizes the results of BERA in different studies.