Electroencephalogram abnormalities in children with autism spectrum disorders.

Children with an autism spectrum disorder (ASD) often are evaluated with electroencephalogram (EEG) studies to assess their risk for seizures or other underlying abnormalities. Their risk is estimated at 7% - 42%. EEG studies were conducted on a subgroup of children while following established practice parameters for evaluating children for ASD. Abnormal EEG results were obtained in 85 (27%) of the 316 children evaluatedfor ASD. Within the subset of abnormal results, 64 children had autism, 10 had an ASD or milder presentation, 6 had another developmental disorder, 3 had Rett syndrome, had Down syndrome, and 1 had Wolf-Hirshhorn syndrome. The abnormal EEG findings included epileptiform abnormalities in 55 patients (65%), and slowing in only 13 patients (15%). The focality of the epileptiformfindings included 26 (30%) in the temporal areas, 24 (28%) in the central area, 20 (23%) in the frontal area, and 7 (8%) in the occipital area. These findings confirm the importance of ongoing medicalfollow-up for children with ASDs, especially for those with abnormal EEG results.