Prevalence, Significance and Clinical Characteristics of Seizures, Epilepsy and Subclinical Electrical Activity in Autism

This manuscript reviews epilepsy, seizures and/or subclinical electrical discharges (SEDs) in individuals with autism spectrum disorder (ASD), including prevalence of epilepsy and SEDs, clinical characteristics of this ASD subgroup and seizure types. The prevalence of epilepsy in ASD is higher than the prevalence of epilepsy in typically developing individuals and depends on age and gender as well as comorbid genetic, metabolic and intellectual abnormalities. Studies suggest that, in ASD, the prevalence of clinical seizures increases with age and that adults with ASD and epilepsy have greater behavioral and cognitive problem as well as elevated mortality. Temporal and frontal lobe epilepsies as well as electrical status epilepticus during sleep syndromes share characteristics with ASD yet these syndromes are rarely diagnosed in ASD. The prevalence of SEDs is very high in ASD. Studies suggest that SEDs and epilepsy share common underlying neuropathology but that children with epilepsy have greater cognitive and behavioral impairments than those with SEDs. Studies, mostly on children with epilepsy, provide evidence that SEDs are related to cognitive impairment. One study suggests that the patterns of temporal and frontal SEDs are related to the ASD diagnosis. These studies are consistent with the cognitive and behavioral abnormalities associated with temporal and frontal lobe epilepsies. This adds support for that fact that SEDs are significant. However, carefully controlled studies on the significance of SEDs in ASD are lacking. [N A J Med Sci. 2015;8(3):113-122. DOI: 10.7156/najms.2015.0803113]