Prognostic factors of infantile spasms from the etiological viewpoint.

We investigated the prognostic factors for mental and physical development and seizure control by dividing the subjects into various etiologic groups in 200 patients with infantile spasms, all of whom (except 48 who died) were aged six years or older. The results were as follows: 1) Intermediate (4-12 mos) onset was found to be a favorable prognostic factor for seizure control in cryptogenic cases, although there was no relation between the age of onset and prognosis in other etiologic groups. 2) There was a significant correlation between the treatment lag and long-term prognosis for mental and physical development only in cryptogenic cases. A short treatment lag (0-2 mos) was associated with a good prognosis. All cryptogenic patients who had no relapse after ACTH therapy developed normally, although in symptomatic cases, there was no correlation between the relapse and the outcome.