Abstracts

Rationale: Studies involving pediatric epilepsy suggest that overall cognitive ability remains relatively stable after surgical intervention, but much of the literature examines cognition shortly after surgery. In some studies involving long-term cognitive outcome, there is indication of improvement in cognitive function in certain populations. Continued investigation of factors that impact long-term cognitive outcomes is warranted. The current study aims to investigate these long-term cognitive outcomes as they relate to EEG status. Methods: Pediatric participants (N = 24) with pharmacoresistant epilepsy were seen for neuropsychological evaluation pre- and post-surgical intervention. Neuropsychological evaluation included an assessment of intellectual functioning (Overall IQ, Verbal IQ, and Nonverbal IQ) as well as determination of post-surgical seizure status. Post-surgical evaluation occurred at least three years following surgical intervention (M = 4.57, SD = 1.62). EEG status at the time of most recent neuropsychological evaluation was classified as normal (or with non-epileptiform slowing) versus abnormal (epileptiform spikes). One-way repeated measures ANOVA was used to assess the overall change in intellectual function across time. Independent samples t-tests were used to explore the relationship of EEG status with IQ change scores. Results: At the time of long-term follow-up evaluation, 17 participants were classified as Engel I status, while 4 were classified as Engel II, and 3 were classified as Engel III. When all participants were analyzed, there were no significant changes in Full Scale IQ (M = -1.33, SD = 12.45) or Nonverbal IQ (M = -2.42, SD = 15.29) across time. However, Verbal IQ (M = -6.25, SD = 11.41) decreased significantly from pre- to post-surgery neuropsychological evaluation [F(1,23)=7.196, p = 0.013]. When considering EEG status at post-surgery evaluation, there was a trend towards a significant difference between groups for change in Nonverbal IQ [t(19.95) = 1.795, p = 0.088). Children and adolescents classified with abnormal EEG at follow-up neuropsychological testing exhibited greater deficits in measures of nonverbal skills (M = -9.13, SD = 10.84) when compared to children with Normal/Slow EEG (M = 0.94, 16.36), whose nonverbal skills remained generally stable across time. Conclusions: Few studies investigate the long-term cognitive outcomes of children and adolescents with epilepsy who undergo surgical intervention. Here, we provide evidence that while overall intellectual function remains stable in most participants, Verbal IQ and Nonverbal IQ may be differentially affected. Factors such as abnormal EEG post-surgery may impact outcomes. With more systematic long-term follow-up assessment, additional variables such as seizure status, surgical location, and neuroimaging variables may further explain variance in outcome. Funding: No funding