Peculiarities of EEG diagnostics in children with autism spectrum disorders

Autism spectrum disorders are now occupying an increasingly large niche among childhood diseases and, according to some experts, have the potential to become a pandemic. Unlike many other disorders, autism spectrum disorders do not have a clear, unified mechanism, either at the cellular, molecular or structural levels. Currently, much literature is devoted to this topic, but there is no scientific consensus about the true reason. Despite a similar clinical picture, the etiopathogenetic mechanisms of these disorders can be different: from dysontogenesis and genetic mutations to exogenous factors. This article presents EEG patterns for various phenotypes and causes of autistic disorders. The functional variability of the brain functioning at different stages of the disease is observed. Theta rhythm (long-lasting and correlating with regression periods) dominates in the EEG picture of autistic disorders in Fragile X syndrome, Rett syndrome and atypical childhood psychosis. This fact makes it possible to assume that the pattern is peculiar to severe autistic disorders. In case of mild autism spectrum disorders or during remission, the beta-rhythm index and the sensorimotor rhythm increase. The alpha rhythm is often abnormal and falls off the age norms in frequency characteristics. Alpha rhythm indicates a favorable prognosis for patients with autism spectrum disorders. The functional variability of the brain functioning at different disease stages was observed.