Abstracts

Rationale: We intended to elucidate the whole clinical course of Dravet syndrome (DS), from infancy through adulthood, for the first time. Methods: Subjects were 32 patients with DS (14 with typical DS and 18 with borderline DS) who were followed from childhood to at least 18 years of age. Their seizures, abilities, and electroencephalogram (EEG) findings were investigated and statistically analyzed. Results: The clinical findings of the patients with typical DS and those with borderline DS became largely similar in adolescence and adulthood. Seizures were intractable in all patients, but suppressed in six (18.8%) during follow-up. Thirty-five (87.5%) of the 40 apparently generalized convulsive seizures that were recorded during ictal EEG at 7 years of age or later were of focal origin. The seizure-free outcomes were significantly correlated with the experience of less than three episodes of convulsive status epilepticus, and also with disappearance of spikes on the follow-up EEGs. The mental outcomes of relatively good intellectual ability were correlated with the presence of occipital alpha rhythms in the background activity of the follow-up EEGs. Conclusions: Prevention of the occurrence of convulsive status epilepticus was indicated to be critically important for the improvement of seizure prognosis in DS.