Auditory brainstem responses as a clinical evaluation tool in children after perinatal encephalopathy

Auditory brainstem responses (ABR) reveals the neurophysiological status of the neural axis. In this study we compared the ABR of healthy children, under 1-year-old, with children who suffered from perinatal encephalopathy (PE).

The purpose of this study was to characterize the ABR differences between children with PE and healthy children in order to identify groups with specific neurophysiological profiles, associated with their neurological condition.

Thirty-six children with perinatal encephalopathy (PE) and 36 healthy children, ages 1-12 months, were studied. The variables considered were: latencies of waves I, II, N1, III, V, and N2; interpeak latency interval (IPL) of waves I-III, III-V, and I-V; as well as amplitudes of waves I, III, and V. The results were analyzed using ANOVA, as well as Ji(2), and Ward's cluster analysis.

The absolute latencies of the ABR showed an inverse correlation with the children's age. Latencies of waves I, II, N1, V, and N2, IPL III-V, and amplitude of waves III and V show significant differences (p<0.05) between healthy and PE children. Children with PE showed greater absolute latencies and larger wave amplitudes than the control group. Ward's cluster analysis, used to define the groups with similar functional characteristics, revealed three groups: fast, intermediate, and slow-responders, depending on their wave latencies and IPL wave amplitudes. These groups were gender- (p<0.03), age- (p<0.0001), and neurological damage- (p<0.01) related.

Our data clearly show that the ABR obtained from PE children differ from ABR obtained from healthy children. PE infants showed larger wave latencies, intervals amplitudes than the control group. Three functional profiles resulted from the groups established using the Ward's method, and these indicate their neurological functional condition.