The Natural History of Infantile Spasms

Abstract

Thirty infants with the syndrome of infantile spasms and mental retardation occurring before the age of 1 year have been followed by clinical and eeg examinations for periods of two to six years. None were treated with corticotrophin or steroids. There was a steady reduction in the number still having spasms and at 3 years over half the patients were free of them. Focal or major fits occurred in one-third of the total and did not show the same tendency to disappear with age. The eegs became more organized and at 3-31/2 years more than one-third were normal. Hypsarrhythmia was rare by this age but was found even at 6 years. Mental improvement was much rarer and only two patients became mentally normal. The mortality rate was 13% by 3 1/2 years. There was little difference between the symptomatic and cryptogenic groups with regard to the rate of disappearance of spasms and eeg improvement. Mental retardation, however, was less severe in the cryptogenic group even at 1 year and this group showed a slight but definite general improvement later, whereas none occurred in the symptomatic group.