Abstract:
Autism spectrum disorder (ASD) is a neurodevelopment disorder characterized by a persistent impairment of communication and social interaction and restricted, repetitive and stereotyped behaviours. Compared with the healthy population, patients with ASD have an increased incidence of epilepsy (2–3% vs. 5–46%, respectively); moreover, several authors have identified the presence of EEG abnormalities in subjects with ASD, in the absence of a diagnosis of epilepsy, with a prevalence ranging from 6.7 to 61%. The EEG abnormalities can include non-epileptiform abnormalities (such as slow activities or asymmetries in background rhythm), and epileptiform abnormalities (spikes or sharp waves, slow waves, generalized wave-spike or generalized polyspikes). Although there is no consensus among researchers, it seems that the EEG anomalies occur more frequently in temporal regions and are revealed during sleep recording. Although the epileptiform abnormalities are considered an expression of underlying brain dysfunction, it is still unclear how these functional abnormalities are related to the clinical phenotype.
However, epileptiform abnormalities were significantly higher in patients with severe forms of autism. Moreover, a higher prevalence of epileptiform abnormalities was found in patients with simple and complex stereotypies, aggressive behavioural patterns, self-harm and hyperactivity. On the other hand, the presence of epileptiform abnormalities was significantly lower in patients with normal cognitive functioning than those with a lower intellectual level. Based on these data, studies suggested that EEG abnormalities are a neurophysiological biomarker for the severity of cognitive and behavioural problems associated with ASD.
