Abstracts

Rationale: A large retrospective study of adults assessed for epilepsy surgery found that many had epilepsy onset in childhood with a significant remission followed by intractable epilepsy (Berg et al Ann Neurol. 2006;60:73-9). Our prospective study documents the frequency of this distressing sequence of events. Methods: We selected patients from the Nova Scotia Childhood Population-based Cohort with symptomatic or cryptogenic partial epilepsy (SFE) and follow up ?10 years. Benign focal epilepsy syndromes were excluded. A significant remission was defined as ?1 year seizure free. Results: Two groups of patients were analyzed: 1) all in the cohort with mental retardation and SFE, 2) a convenience sample (about 50% of those in the cohort) with normal intelligence and SFE. Of the 51 with SFE and mental retardation, age of epilepsy onset averaged 5 4.3 years and average follow up was 22.2 4 years. At the end of follow up, average age was 26.6 4.8 years, when 13 (25%) had intractable epilepsy and one had successful epilepsy surgery. Only 3 had a significant remission, ranging from 1.5 to 4.8 years. The time from epilepsy onset to the beginning of the remission was 0.8 to 5.5 years. One patient attempted to discontinue AED treatment during remission. In each case remission was again followed by intractable epilepsy. Of the 81 with normal intelligence and SFE, age of onset averaged 7.2 4.5 years and follow up averaged 26.9 4.9 years. Age at the end of follow up averaged 34 6.8 years. Eleven (14%) had epilepsy surgery of whom 6 had a significant remission prior to surgery lasting 1 year (n=1), 1-3 years (n=4) and 5 years (n=1). The interval between epilepsy onset and the start of remission was <1 year (n=2), 1.5-4.5 years (n=3) and 8 years (n=1). Three attempted to discontinue AED treatment during remission although intractable seizures returned promptly. An additional 10 (12%) patients with normal intelligence and SFE developed intractable epilepsy but did not undergo surgery. Five had a significant remission lasting 1-2 years (n=4) and 5 years (n=1). The interval between onset of epilepsy and the start of remission was <1 year (n=1), 6 years (n=1), 10-13.4 years (n=4). Five had attempted to discontinue AED treatment during their remission. Combining the groups, 35 of 132 (27%) had intractable epilepsy with/without epilepsy surgery. 69% of intractables had a significant but transient remission ?1 year although only 4 had a remission >4 years. Nine (26%) attempted to discontinue AED treatment during remission. Conclusions: Over 10-30 years of follow up, about two thirds of children with intractable symptomatic or cryptogenic focal epilepsy will have a substantial but temporary remission. The remissions usually begin after a few years of active epilepsy and most are relatively short (< 2 years) but in ~25% are long enough to attempt discontinuing AED treatment. At least 5 years of remission is needed before children with intractable partial epilepsy can be nearly certain that their epilepsy has resolved.