EPIDEMIOLOGIC FEATURES OF INFANTILE SPASMS IN ICELAND

We determined the average annual incidence of epilepsy characterized b y infantile spasms (IS) in Iceland based on the 13 cases identified in a 10-year interval (1981-1990). The cumulative incidence was 3 in 10, 000 five births. Males were more frequently affected than females. All patients responded completely (10) or partially (3) to ACTH or steroi d therapy. At follow-up, all children with cryptogenic IS are seizure- free and have developed normally intellectually. One of the children w ith cryptogenic IS has mild spastic diplegia. All children in the symp tomatic group are mentally retarded, and 5 of 7 continue to have unpro voked seizures. We detected no evidence for familial aggregation, and the incidence of seizures or epilepsy did not appear to be increased i n first-degree relatives of cases. The proportion of cases with a favo rable outcome was greater than that reported in most clinical series.