Frequent association of autism spectrum disorder in patients with childhood onset epilepsy.

Autism spectrum disorder (ASD) has a close relationship with epilepsy. This study retrospectively examined patients with epilepsy associated with ASD. Among the 519 patients with epilepsy, 79 patients (15.2%) had ASD. Sixty-two patients had idiopathic ASD and 17 had secondary ASD. The epilepsy patients with idiopathic ASD were retrospectively analyzed. There were 47 males and 15 females, ranging from 2 to 43 years of age (median 11 years). The most frequent age at the onset of seizures was 4 years, and 85% occurred before 10. ASD was detected after the onset of epilepsy in 29 cases (46.8%), and eight of them had been overlooked for more than five years. Most of these were high-functioning ASD cases. The most frequent type of seizure was a complex partial seizure (CPS; 68%). Paroxysmal activities on EEG were localized in the frontal area in about half of the cases. Multiple anti-epileptic drugs were used in 33.8% cases (two in 17.7%, three in 16.1%), and 67.3% of the patients were seizure-free for more than two years. An amelioration of the autistic symptoms occurred after epilepsy treatment in five cases (8%). CPS with frontal paroxysms occurring from one to nine years of age seems to be characteristic of epilepsy associated with ASD.