Abstracts

RATIONALE: Epilepsy occurs in 10-30% of individuals with autism. A retrospective review of EEG (including video EEG) data of 38 children diagnosed with autism over 2 year period is presented. The association between autism and specific epileptiform EEG abnormalities is not firmly established. It has been suggested that the routine awake EEG frequently shows epileptiform abnormalities. This retrospective study addresses the utility of the routine EEG in the evaluation of children with autism.
METHODS: A retrospective review of EEG[ssquote]s and Video EE[ssquote]s was performed in all children referred with a diagnosis of autism within last two years. EEG was performed at one location (SUNY) and reviewed by one of the authors (M.A.). The EEGs of all patients were recorded on 18-channel instruments with electrodes placed according to the international 10-20 System, using digital tracing monitor that enables review of both referential and bipolar montages. The recording was done during awake, sleep, photic stimulation and hyperventilation, when possible. EEG[ssquote]s were classified as normal, abnormal but not epileptiform (e.g. slowing of the background), abnormal epileptiform with focal onset, and abnormal epileptiform with generalized onset. Children with more than one unprovoked seizure and/ or epileptiform EEG were diagnosed with epilepsy.
RESULTS: Thirty eight children (34 males) with a diagnosis of autism were refered for EEG. Three patients had additional diagnoses, one of Asperger syndrome and two of Landau-Kleffner syndrome. Age range was 1 to 15 years. In 12 children episodic events thought to be seizures were described, and two had history of febrile convulsions. EEG was abnormal in 13 children, of which seven had epileptiform abnormalities- focal in three patients and generalized in four patients. Six of seven children with epileptiform EEG had clinical seizures. In two children with a normal 48 hour video EEG, review of home video revealed evidence of partial complex seizures. Of the 26 children without clinical seizures, one had an abnormal epileptiform EEG.
CONCLUSIONS: Epilepsy was diagnosed in 23.7 % of children with autism referred for EEG. In 16% there were episodic events and epileptiform EEG, 5% had clinical seizures with a normal EEG. The prevalence of epilepsy are higher than chance event and supports prior studies showing that epilepsy and autism are comorbid phenomena and may be related to a common brain abnormality. Epilepsy should be suspected in children in the autism spectrum who have paroxysmal events. Review of home or school videos in addition to routine EEG may help in clarifing the diagnosis. In our study, routine EEG without clinical seizures in children with autism had yield of only 4%, and it is not recommended as routine clinical practice.