Abstracts

Rationale: About half of childhood pharmacoresistant epilepsies have malformations of cortical development [MCDs, including cortical dysplasias (FCDs)]. Although MCDs are a major pathology in pediatric epilepsy, little is known about their postoperative cognitive outcomes. This study characterized cognitive outcomes in children and young adults with MCDs who underwent resective epilepsy surgery and sought to identify factors associated with postoperative cognitive outcomes.

Methods: 98 patients [age=13.5 years, 47% female, 75% unilobar resection, 46% included temporal lobe resection] completed comprehensive neuropsychological evaluations before and 6-12 months after surgery. Change scores were calculated and categorized as improved, no change, declined using reliable change indices for children with epilepsy (RCIs; Busch, 2015). Base rates of change were calculated for each cognitive domain. Chi-square and Exact Tests examined group differences as a function of pathology type (i.e., FCDs vs. other MCDs), and a series of univariate logistic regressions was constructed where dependent variable was postoperative decline (vs no decline) or improvement (vs no improvement) and independent variables were demographic, disease, and surgical variables including pathology subtype. Finally, postoperative outcome across domains (No Decline, Focal Decline, Global Decline or No Improvement, Focal Improvement, Global Improvement) was examined using univariate ordinal logistic regressions.

Results: There was a large proportion of children whose scores remained stable or improved following surgery (74-100%) within the individual cognitive domains (Figure 1). When declines were observed, they were most often in language (26%), followed by verbal memory (16%) and executive function (15%). Children with MCDs had shorter duration of epilepsy and were more likely to have resections that included the temporal lobe than those with FCDs, but there were no differences in cognitive outcome as a function of pathology subtype. Patients with lower preoperative cognition were more likely to show improvements and less likely to show declines in most cognitive domains. Improvements in visuospatial skills and verbal memory were associated with surgery in the nondominant hemisphere.

Conclusions: There was a large proportion of children whose scores remained stable or improved following surgery (74-100%) within the individual cognitive domains (Figure 1). When declines were observed, they were most often in language (26%), followed by verbal memory (16%) and executive function (15%). Children with MCDs had shorter duration of epilepsy and were more likely to have resections that included the temporal lobe than those with FCDs, but there were no differences in cognitive outcome as a function of pathology subtype. Patients with lower preoperative cognition were more likely to show improvements and less likely to show declines in most cognitive domains. Improvements in visuospatial skills and verbal memory were associated with surgery in the nondominant hemisphere.

Funding: This study was funded by the American Epilepsy Society (Junior Investigator Research Award) and The Cleveland Clinic Epilepsy Center