[Interest of electroencephalogram in autism]

Autism spectrum disorders (ASD) have been associated with physiopathology in cerebral organization and function. Electroencephalography is a noninvasive technique that provides information about brain electrocortical activity. Electroencephalographic (EEG) studies using power spectra have documented differences associated with ASD, particularly in frontal areas that have been functionally linked to cognitive functions that are disrupted in individuals with ASD. Furthermore, EEG studies confirm coherence changes in individuals with ASD. Many studies have also reported high rates of interictal epileptiform EEG abnormalities in children with ASD with or without history of seizures. Several polysomnography studies have confirmed the presence of disrupted sleep architecture in children with ASD. Polysomnographic abnormalities include reduction of REM sleep, longer sleep latency, increased arousals, lower sleep efficiency, increased stage 1 sleep and decreased slow wave sleep as well as decreased density of spindle activity. The objective of this review is to present research data on the EEG findings in patients with ASD, with emphasis on their power EEG, coherence EEG, epileptiform EEG abnormalities and sleep disorders.