Risk of recurrence after an initial unprovoked seizure.

A cohort of 424 patients was followed to determine the patterns of risk for recurrence after an initial unprovoked seizure. Overall, the risk of recurrence was 36% by 1 year, 48% by 3 years, and 56% by 5 years. The risk of subsequent seizures was lower for patients with idiopathic seizures than for those whose seizures had a presumed etiology. Among cases for which initial seizure was classified as idiopathic, EEG abnormalities, abnormal neurologic examination findings, and initial partial seizures were identified as significant independent predictors of higher recurrence risks.