The time taken to develop intractability of epilepsy was determined prospectively in a cohort of 613 children followed in the Connecticut Study for a median of 9.7 years and reported by researchers from Northern Illinois University, DeKalb, IL; University of California Los Angeles, CA; Yale Medical School, New Haven, CT; and Albert Einstein College of Medicine, Bronx, NY. Intractability was defined in two ways: 1) 2 drugs failed, 1 seizure/month (average) for 18 months (stringent definition), and 2) failure of 2 drugs. Delayed intractability was defined as 3 or more years after epilepsy diagnosis. Intractability (stringent form) developed in 83 children (13.8%), and the 2-drug definition of intractability was met by 142 (23.2%). Intractability was delayed in 26 (31.3%) children meeting stringent and in 39 (27.5%) meeting the 2-drug definition. Intractability varied with the epilepsy syndrome and was delayed more often in focal than catastrophic (including encephalopathic) epilepsies (stringent: 46.2 vs 14.3%, p=0.003; 2-drug: 40.3 vs 2.2%, p<0.0001). Early remission preceded delayed intractability in 65.4 to 74.3% of cases. After developing intractability, 20.5% entered remission, and 13.3% were seizure-free at last follow-up. Referral to surgery may be delayed for 20 or more years, because of this interim period of remission. 
COMMENT. In the earlier Dutch study of 453 children with newly diagnosed epilepsy followed prospectively for 5 years , significant variables for the worst outcome group included a symptomatic or cryptogenic etiology, early age at onset, and a history of febrile seizures. Of 108 (24%) patients with a terminal remission (TS) of <1 year, 27 had intractable seizures at 5 years. Of patients receiving 2 or more AEDs, almost 60% had a TR5 >1 year. AEDs were successfully withdrawn in 227 (59%). The course of epilepsy was constantly favorable in 51%, steadily poor in 17%, remitting after intractability in 25%, and deteriorating in 6% (Ped Neur Briefs August 2004;18:57-59).