Correlations between EEG abnormalities and clinical phenotypes in a population of children with autism spectrum disorder

EEG abnormalities (EA) have recently been proposed as a way to understand the pathophysiology of the Autism Spectrum Disorder (ASD). The present study aims to determine whether there are peculiar correlations between EA in autistic patients and clinical phenotypes. We collected information about patient's past medical and developmental history and investigated clinical phenotypes using the observation and standardized instruments in a cohort of 111 outpatients with ASD or at risk for ASD. Then we proceeded to investigate the association between EA and phenotypic characteristics. In our cohort we found a significant frequency (90%) of moderate/severe autism spectrum symptoms (corroborated by results from standardized tests, such as ADOS-2). Epileptiform EA detected in our sample were mainly focal, with a predominantly left fronto-central temporal region localization. Generalized or widespread epileptiform EA during sleep EEG was significantly correlated with non-verbal profile, greater impairment in terms of social interaction, and higher ADI-R scores in the communication and language scale. In the current study, the presence of widespread epileptiform EA correlates with a more severe clinical presentation, in particular with a non-verbal profile and impairment in social interaction. The prevalent detection of focal EEA in the left fronto-central temporal region could demonstrate the hypothesis of dysfunction of the mirror neuron system and Wernicke’s area. However, it is necessary to understand if EA may be considered an epiphenomenon of the underlying neural dysfunction or whether there is a causal relationship with the autism phenotypes. • EEG studies have the potential to make important contributions to understanding the pathophysiology of ASD. • Epileptiform EEG abnormalities in our sample were mainly focal, predominantly in a left fronto-central temporal localization. • epileptiform abnormalities during sleep EEG were correlated with greater impairment in interaction and communication. • the correlation between EEA and impairment in interaction could support the dysfunction hypothesis of the mirror neuron system and Wernicke’s area.