Abstracts

Rationale: Recent studies have documented neuropsychological functioning beginning soon after seizure onset (e.g., Fastenau et al., 2009, Neurology; Hermann et al., 2006, Brain; Oostrom et al., 2003, Pediatrics), but there are no truly prospective studies documenting neuropsychological functioning before seizure onset and following those children longitudinally. We prospectively examined neuropsychological functioning in a small group of healthy children who later developed seizures. Methods: In a 3-year prospective study, 350 children ages 6-14 years were identified following their first recognized seizure, and 253 healthy siblings were recruited as controls. Of the 253 siblings, 15 developed seizures during the 36-month follow-up period; 8 of those had completed NP prior to the seizure (some siblings entered the study before age 6 and were ineligible for NP at that time due to their age), and 5 of those with baseline NP repeated testing after seizure onset. NP at baseline (M=2.8 months after first seizure for the original seizure group) yielded 4 age-corrected factors: Language, Verbal Memory & Learning, Processing Speed, Attention/Executive/Construction skills (higher scores are better) (Byars et al., 2007, Epilepsia). Analysis of variance (ANOVA) was used to compare siblings without seizures to siblings with seizures on NP at baseline, NP at 36-months, and NP change from baseline to 36 months. Tukey s method was used to adjust for multiple comparisons.Results: The siblings with seizures did not differ from siblings without seizures at baseline (i.e., before they developed seizures) on any of the NP factor scores (p>.10), and the differences between those groups yielded small effect sizes (Cohen s d ranging from +0.01 to -0.29). At the 36-month follow-up (after onset of seizures), however, the siblings with seizures scored well below the siblings without seizures on all four NP factor scores. Although the parametric comparisons of means did not reach statistical significance with this very small sample size, the effect sizes were medium to large (Cohen s d ranging from -0.37 to -0.87). Most dramatic were declines in Language and Processing Speed in the siblings with seizures compared to stability in the siblings who never developed seizures during the 3-year study period (see Figure).Conclusions: In this group of children who were tested before their first-ever seizure and again after seizure onset, there appeared to be dramatic declines in Language and Processing Speed. This finding parallels changes observed in a subgroup of the original seizure cohort, which was followed 3 years following the first seizure. Although this study is limited by very small sample size, it provides a unique and truly prospective window into the earliest NP changes following the very first seizure. Funded by NIH/NINDS R01 NS22416 (PI: Austin).