The high prevalence of epilepsy in children with autism supports a neurobiologic etiology for autism. It remains unclear whether seizures and epileptiform activity on the EEG are causative or comorbid. It is also uncertain if focal epileptiform EEG abnormalities may be associated with stable cognitive impairment. Even less clear is whether these EEG abnormalities can result in the combination of language and social dysfunction seen in autistic spectrum disorders.