Objective: To determine the initial Brainstem Auditory Evoked Response (BAER) abnormalities in neonates with hyperbilirubinemia and the possible reversibility of abnormal BAER after therapy.
Design: Prospective cohort study.
Setting: Tertiary care hospital.
Subjects: 30 term neonates with hyperbilirubinemia (S. bilirubin < 15 mg/dl) as cases and 25 normal term neonates as controls.
Methods: Duration of study was from August 1995 to August 1996. BAER were recorded before therapy at peak hyperbilirubinemia, after therapy, and the age of 2-4 months using electric response audiometer (Nihon Neuropack Four Machine). Denver Development Screening Test (Denver II) was performed at 1 year of age.
Results: Seventeen out of thirty (56.7%) neonates with hyperbilirubinemia showed abnormalities on initial BAER. Commonest abnormality seen was raised threshold of wave V in 12 neonates (40%). Other abnormalities observed were absence of all waves at 90 dB (23.3%), prolongation of latencies of various waves (26.7%) and prolongation of various intervals (26.7%). Abnormalities in BAER correlated significantly with bilirubin level. After therapy abnormalities reverted back to normal in 10 cases but persisted in 7 out of 17 (41.17%) cases with initial abnormal BAER. Development screening at 1 yr was abnormal in 3 infants all of whom had persistent abnormalities in BAER.
Conclusion: Serial BAER is a useful, non invasive tool to detect neurodevelopment delay secondary to neonatal hyperbilirubinemia.