Auditory brainstem response for Sri Lankan children under 5 years of age: Normativedata

For years Sri Lankan Audiologists resorted to western norms in the interpretation of Auditory Brainstem Response (ABR) in the absence of national standards. The study focused on establishing normative data on ABR for Sri Lankan children below 5 years.

ABR was performed on 258 healthy children between 6 weeks and 5 years of age to gather data on absolute latencies and inter-peak latencies.All inter-aural differences were within 0.2-0.4ms. The mean inter-aural difference for the study sample was significantly small (-0.0204ms to 0.0286ms). Mean values of absolute latencies for waves I, III, V for the 6-week age group at 30dBnHL were 3.33 ms, 5.91 ms and 8.27 ms respectively. Mean values of inter-peak latencies of wave I-III, III-V, I-V were 2.08 ms, 2.36 ms and 4.76 ms respectively for the 6-week age group at 30 dBnHL.

The normative ABR data obtained in this study may be used across audiology clinics in Sri Lanka as a baseline measurement to diagnose hearing loss among children from infancy to 5 years of age when children are tested in their natural sleep and insert earphones are used. The mean value plus 2 standard deviations for each ABR measure may be used as the upper limit cutoff values.  Hence this study helps eliminate misdiagnosis and under-diagnosis of hearing loss in children.