Abstracts

Rationale: There are two desirable outcomes in childhood onset epilepsy – few seizures and good social outcome. To assess the likelihood of the combination of these two2 outcomes this study addresses children with focal onset seizures that evolve to bilateral clonic movements (FBTC) (previously focal with secondary generalization). FBTC was chosen because children with most other seizure types have too many seizures to count. Methods: Patients with FBTC were selected from the Nova Scotia population-based study of childhood onset epilepsy with ≥20 years follow up. Eligible patients had 2 or more unprovoked seizures including at least one focal onset seizure that evolved to bilateral tonic clonic (FBCT) and a follow up of >20 years. Patients with Rolandic epilepsy were excluded. The total number of lifetime FBCT seizures was assessed prospectively and categorized as 1-5, 6-10, 11-20, 20-99 and >100. Cases were restricted to those with normal intelligence to allow evaluation of social outcome at the end of follow up. Social outcome was assessed by a semi-structured interview and based on eight adverse outcomes (no high school graduation, unemployment, living alone, no long term romantic partner (>3months), at least one close friend, an unplanned pregnancy outside a stable relationship (>6 months), a DSM mood disorder, or other major psychopathology and personal poverty. A good social outcome was defined the absence of any of these adverse social outcomes. Results: There were 166 eligible patients with normal intelligence, focal onset seizures that evolved to bilateral tonic clonic (FBTC) and ≥20 year follow up (mean 27.7±4 , range 24-42 years). Numbers of FBTC seizures were: 1-5 n= 48(29%); 6-10 n=33(20%); 11-20 n=27(16%); 21-99 n=29(17%); >99 n=34(20%); uncertain 4. Of the 166, social outcome data was available for 148. Overall 30% had had no adverse social outcomes. For those with <6 total seizures, 19 (43%) had no adverse social outcomes and of those with <11 total seizures, 30/73 (41%) had no adverse social outcomes. Thus, an excellent outcome of <6 seizures and a good social outcome occurred in 12.5% (43% of 29%). Of those with >10 seizures 14/73 (20%) had no adverse social outcomes with no statistical difference with increasing seizure numbers beyond 10. The rate of adverse social outcomes for those with <11 versus those with >10 seizures was statistically different (p=0.004).Of the total of 166 patients, 40% had ≥10 seizures plus ≥1 adverse social outcome. Once ≥10 seizures had occurred, 80% had ≥1 adverse social outcome. However, of the 166 with FBTC, only 67 had FBTC alone with no focal aware and no focal with impaired awareness seizures. Of those with FBTC alone, 29% had <6 seizures and no adverse social outcomes and 50% had <11 seizures and no adverse social events. Of those with >10 seizures, 22% had no adverse social outcomes. For those with FBTC + focal with impaired awareness seizures, the rate of adverse social events for those with <11 FBTC seizures versus those with >10 FBTC seizures was not statistically different (p=0.2).Of the 59 with FBTC plus focal seizures with impaired awareness, 22% had no adverse social events. Of this group 12.3% had <6 FBTC and no adverse social events. Of the 11 with FBTC plus focal aware seizures, 64% had no adverse social events. Of the 18 with FBTC plus both focal aware and focal with loss of awareness, 33% had no adverse events. Conclusions: Only 12% of normally intelligent children with focal onset seizures that evolve to bilateral clonic movements (FBTC) had relatively “easy going” epilepsy with a total of <6 FBTC seizures and normal social outcome over a >25 year follow up. An additional 7% had the less satisfactory outcome of 6-10 FBTC but normal social outcome. For those children who experienced >10 seizures, 80% had ≥1 major adverse social outcome. Relatively “easy going” epilepsy with few FBTC seizures and a good social outcome is sadly uncommon. Funding: No funding