Study of auditory evoked potentials in autism.

Background: electrophysiological assessment of hearing in autistic individuals.

Aim: to characterize the findings obtained in the electrophysiological assessments of autistic individuals, as well as to compare these to the results obtained for individuals of the same age who present typical development.

Method: 16 individuals with autism (study group) and 25 normal individuals (control group), ranging in age from eight to 20 years underwent anamnesis, pure tone audiometry, speech audiometry, acoustic immitance measures, brainstem auditory evoked potential (BAEP), middle latency response (MLR) and cognitive potential (P300).

Results: the study group presented altered results in all auditory evoked potentials, showing statistically significant differences when compared to the control group. Concerning the types of alterations found in the study group the following results were observed: higher occurrence of lower brainstem alteration in the BAEP, both (electrode and ear effects occurring simultaneously) in the MLR, and absence of response in the P300. In the quantitative data analysis, statistically significant differences between the groups were found only for the BAEP regarding the latencies of waves III and V and interpeaks I-III and I-V.

Conclusion: autistic individuals present altered BAEP and P300, suggesting impairment in the brainstem auditory pathway and cortical/subcortical areas.