Abstracts

Rationale: Post-operative neuropsychological outcomes are critical to the reaching the ultimate goal of precision medicine such that we are able to determine optimal approaches and timing of surgery in youth with epilepsy. This is the first report of postoperative neuropsychological outcomes in a multisite consortium.

Methods: 244 children (ages 6 months to 20 years old, 46.3% female, 80.3% White, 84% Non-Hispanic) who underwent surgery and had pre- and post-operative surgical data for any of four indices from an intellectual functioning measure (e.g., Verbal IQ (VIQ); Nonverbal IQ (NVIQ), Working Memory Index (WMI), Processing Speed Index (PSI)) or nine subscale scores from a parent-reported executive functioning measure (Behavior Rating Inventory of Executive Functioning (BRIEF)) were included. This sample had abnormal MRI (76%); 51.5% underwent left hemisphere surgery, 43.8% right, and 4.7% (bilateral or midline), 33.7% were intended to be pallative rather than definitive procedures, 68.8% were seizure free or had a 90% reduction at a mean follow up of 21 months (range 1 month-6 years). Repeated measures analyses were conducted to assess group change. Reliable Change Indices (RCI) cutoffs were applied to determine percentages of meaningful change on an individual basis (Decline, No Change, Improvement). Change scores across measures were correlated with epilepsy characteristics.

Results:
Across 12 sites, a majority of children (87-60%) had a measure of IQ change, while a subset (29%) had pre and post BRIEF data (Table 1). Average follow-up was 14 months (range 6 months to 4 years). Only two scores were different on a group basis: working memory performance was worse after surgery (p=.026), while parent report of emotional control (p=.048) was improved. There were trends for parent report of inhibitory control and organization of materials to be improved. Across all measures, there was substantial individual variability with 7-33% of children showing improvements and 13-29% showing declines according to RCI cutoff scores (Figure 1). Earlier age of seizure onset was correlated with greater VIQ and PSI change. Older age at postoperative testing and longer time since surgery was significantly associated with improvement in some aspects of EF. Location of surgery and seizure outcome was not significantly associated with neuropsychological outcomes.




Conclusions:
While mean change was significant for more fluid cognitive skills such as working memory and aspects of EF, all measures had a subset of children who had meaningful change, either improvement or decline. Preliminary analyses examining age at onset, testing, and time since surgery are related to some outcomes. Other neuropsychological domains will be examined in future work. Additional analyses are also needed, including prediction models, to better determine the children who are greatest risk for decline or most likely to improve in functioning.




Funding: Pediatric Epilepsy Research Foundation