POPULATION-BASED STUDY OF SEIZURE DISORDERS AFTER CEREBRAL INFARCTION

We performed the first population-based study that determined the magn itude of the risk and identified the factors predictive of developing seizure disorders after cerebral infarction. Five hundred thirty-five consecutive persons without prior unprovoked seizures were followed fr om their first cerebral infarctions until death or migration out of Ro chester, Minnesota. Thirty-three patients (6%) developed early seizure s (within 1 week), 78%; of which occurred within the first 24 hours af ter infarction. Using multivariate analysis, the only factor predictiv e of early seizure occurrence was anterior hemisphere location of infa rct (odds ratio 4.0; 95% CI 1.2 to 13.7). Twenty-seven patients develo ped an initial late seizure (past I week), whereas 18 developed epilep sy (recurrent late seizures). Compared with the population in the comm unity, the risk during the first year was 23 times higher for initial late seizures and 17 times higher for epilepsy. The cumulative probabi lity of developing initial late seizures was 3.0% by 1 year, 4.7% by 2 years, 7.4% by 5 years, and 8.9% by 10 years. Independent predictive factors on multivariate analysis for initial late seizures were early seizure occurrence (hazard ratio of 7.8 [95% CI 2.8 to 21.7]) and stro ke recurrence (3.1 [1.2 to 8.3]). Both early seizure occurrence (16.4 [5.5 to 49.2]) and stroke recurrence (3.5 [1.2 to 10.5]) independently predicted the development of epilepsy as well. We also found that ear ly seizure occurrence predisposed those with initial late seizures to develop epilepsy.