A longitudinal study on epilepsy: with special reference to recurrence of seizure after long seizure-free period.

The clinical course was investigated of 137 epileptic patients who had been under continuous observation and therapy for the past 11 to 23 years. When a remission of epilepsy was defined as a seizure-free period for three years and a relapse was defined as an occurrence of seizures after the remission, the remission rate was 45%, but 32% of the subjects had experienced the relapse. When the term of three years in the definition of remission and relapse was altered to five years, the rates of remission and relapse shifted to 36% and 20%, respectively. A relapse of seizure was found more often in grand mal of primary generalized epilepsy than other types of seizures. Especially, no relapse was observed in benign epilepsy of children with centro-temporal EEG foci.