RESUMO
BACKGROUND: Abnormalities on electroencephalography (EEG) results have been reported in a high percentage of children with Autism Spectrum Disorder (ASD). The purpose of this study was to explore the prevalence of EEG abnormalities in a clinical population of pre-school children with Autism Spectrum Disorder and the differences in terms of the following phenotypic characteristics: adaptive behavior, executive functioning, severity of Autism Spectrum Disorder core symptoms, and comorbidity symptoms. METHODS: A cross-sectional analysis of 69 children who attended the Autism Spectrum Disorder early diagnosis program with electroencephalography and clinical diagnosis was performed. A battery of questionnaires was also made to parents to evaluate emotions, behavior, and functional skills for daily living. RESULTS: Out of 69 pre-school children with Autism Spectrum Disorder, twenty nine (42%) had abnormalities in electroencephalography results. The group with abnormal epileptiform electroencephalography exhibited more impairment in executive functioning and social-relationship coexisting symptoms. CONCLUSIONS: The presence of an abnormal epileptiform electroencephalography in pre-school children with ASD already suggests a worse development in clinical features.