Objectives: So-called “idiopathic” autism which showed no major complications before the diagnosis is well-known as one of the risk factors for epilepsy. This prospective follow-up study aimed to clarify the characteristics of epilepsy in the autism; onset of epilepsy, seizure types, EEG findings and epilepsy outcome and the differences as a group between the autism with epilepsy and those without epilepsy.
Methods: One hundred thirty individuals with the autism or atypical autism diagnosed in childhood followed up over 10 years and were evaluated almost every year up to ages 18–35 years. Their medical records related to perinatal conditions, IQ, social maturity scores and several factors of epilepsy were reviewed at the time of October in 2005.
Results: Thirty three of the follow-up group or 25% showed epileptic seizures. The onset of epilepsy was distributed from 8 to 26 years of age. Two types of seizure were observed; partial seizure with secondarily generalized and unclassified grand mal (details unknown). Although 18% of the non-epileptic group showed epileptic discharges on EEG, 68% of the epileptic one revealed epileptiform EEG findings before the onset of epilepsy. Two thirds of the epileptics were considered to be active. No difference was obtained concerning the sex ratio, typical/atypical ones and past history of febrile seizures between the epileptic and non-epileptic groups. Lower IQ, lower social maturity score and more frequent occasion of psychotropics prescribed were seen in the epileptic group compared to in the non-epileptic one.
Conclusion: Idiopathic autism as well as “symptomatic” autism was reconfirmed as the high risk factor for epilepsy. The first epileptic seizure appeared over 8 years old. Major seizure types seemed to be partial seizures with secondarily generalized. Epileptiform EEG findings predict the following epileptic seizures in adolescence/early adulthood. Epilepsy is one of unfavorable factors on prognosis for individuals with autism.
