A retrospective evaluation of 26 case records of patients with diagnoses of symptomatic infantile spasms and classic hypsarrhythmia is reported from the Division of Pediatric Neurology, University of Minnesota Medical School, Minneapolis, MN. Seventeen (65%) had complete control of spasms and 9 did not respond. Both responders and nonresponders received similar ACTH dosages (87.4 and 84.5 U/m2, respectively). High-dose ACTH (>100 U/m2) was not more effective than lower dose regimens. Favorable outcome was associated with late onset (>8 months of age) and prompt treatment (1 month of onset). Responders either improved or did not deteriorate in development, whereas nonresponders were more impaired neurologically. 
COMMENT. The control of seizures in responders occurred in 1.6 weeks (0.5-6), and hypsarrhythmia disappeared in all. Despite the symptomatic nature of the infantile spasms and pre-treatment neurologic abnormalities, the results of moderate and relatively short duration ACTH dosage can be satisfactory provided seizure onset is delayed until after 4 months of age and treatment is initiated promptly. High dose regimens with increased risk of serious toxicity are apparently not justified. The need for early diagnosis and treatment has been emphasized previously.