Abstracts

Rationale: SMEI (or Dravet syndrome) is an intractable epileptic encephalopathy occurring in the first year of life in a previously normal infant. Patients present recurrent and usually febrile seizures, resulting frequently in status epilepticus. Other seizure types including myoclonic, absence and partial seizures occur later with concomitant developmental delay and ataxia. Cognitive outcome is poor and only a few data are reported in the literature showing global mental retardation, severe impairment of language and autism spectrum disorders. In order to better delineate the cognitive outcome in this syndrome, we performed a prospective study in our series of typical SMEI as first described by C. Dravet. Methods: Cognitive scales used were Brunet-Lezine or WPSSI, according to the patient’s age. Parent’s Conners and Achenbach scales were performed to assess the behavior of the child. Daily life possibilities of the child were examined with Vineland scale. Analysis were performed regarding 4 age-groups : less than 15 months, 16-47 months, 4-6 years and above 7 years. Results: We evaluated 64 children, aged 1-20 years: 53 had quantified scores and 23 had at least 2 evaluations. Evaluation was not achieved in 11 patients because of major behavioural impairments in 9 and lack of communication in 2. Seventy two percent of children have SCNA1 mutation. Regarding global mental level, all children less than 15 months (n=8) were normal but none after 4 years. Over 4 years, 42 out of 57 evaluations showed mild or moderate delay. Only 7 evaluations showed severe delay. Regarding language, all patients were able to produce at least isolated words. 55% (29 out of 53) aged over 4 were able to produce coherent sentences including 17 children over 7 years. Behavior was normal in 25 to 32% over 15 months. Between 15 months and 6 years, hyperactivity and attentional disorders predominated (26 to 41%) whereas conduct disorders predominated after 7 years (53%). Outcome was not correlated to SCN1A mutation status. No significant correlation was found between outcome and the age of onset, the number of status epilepticus and the age of the first status. Conclusions: Our series shows better cognitive and behavioural outcome than previously reported, mainly on language and socialization. This could be explained by new AEDs therapy for SMEI.