Parent Reported Executive Functioning Does Not Predict Memory Dysfunction in Pediatric Epilepsy and Attention-Deficit/Hyperactivity Disorder
Objective: Epilepsy and Attention-Deficit/Hyperactivity Disorder (ADHD) children are vulnerable to executive functioning and memory difficulties. The interaction between EF and memory is important to consider as EF impairments may put children at risk for experiencing memory difficulties which can impact their academic performance and quality of life. However, the evidence for the impact of EF on memory is very limited with only two studies to date focusing on this association (Rzezak et al., 2012; Sepeta et al., 2017). This was the first study to research the impact of executive dysfunction on memory in the pediatric epilepsy and ADHD population. Method: All participants (n=104) underwent a comprehensive neuropsychological evaluation to assess current level of cognitive functioning. The total sample was further subdivided into four diagnostic groups: intractable epilepsy group, controlled epilepsy group, comorbid epilepsy/ADHD group, and ADHD group. The Behavior Rating Inventory of Executive Function (BRIEF) was used to examine parent-reported executive functioning, while the California Verbal Learning Test – Children’s (CVLT-C) and Children’s Memory Scale (CMS: Stories, Dots, and Faces subtests) were used to measure memory. Results: FSIQ, BRIEF GEC, and age of seizure onset provided a statistically significant prediction of every delayed memory score for the epilepsy group [(CMS Stories Delay (F(3, 67) = 5.972, p = .001), (CVLT-C LDFR (F(3, 67) = 5.593, p = .002), (CMS Faces Delay (F(3, 66) = 3.918, p = .012), (CMS Dots Delay (F(3, 67) = 3.391, p = .023)]. Similarly, FSIQ and BRIEF GEC provided a statistically significant prediction for a majority of the memory scales [(CMS Dots Delay (F(2, 27) = 5.824, p = .008), (CVLT-C LDFR (F(2, 27) = 5.318, p = .011), (CMS Stories Delay (F(2, 27) = 4.055, p = .029)]. However, FSIQ was the only unique predictor for both the epilepsy and ADHD groups. Regarding memory, the epilepsy group demonstrated average recognition, learning efficiency, learning slope, total word recall, and immediate and delay recall scores. The ADHD group also demonstrated average immediate and delay recall scores, initial attention, as well as no interference effects. There were significant diagnostic group differences such that the epilepsy group exhibited significantly lower scores on CMS Faces Delay (U = 666, p = .002) compared to the ADHD group. Additionally, the intractable epilepsy group had significantly lower CMS Story Delay memory scores compared to that of the controlled epilepsy and ADHD groups (F(3, 100) = 4.14, p = .008), as well as significantly lower CMS Dot Delay memory scores compared to that of the ADHD group (F(3, 100) = 2.90, p = .039). Conclusions: Overall, this study found that intellectual functioning, executive functioning, and age of seizure onset were significant predictors for every delayed memory score in children with epilepsy. Similarly, intellectual and executive functioning were significant predictors for the majority of the delayed memory scores in children with ADHD. However, intellectual functioning was the only unique predictor in both models. Regarding memory, the overall epilepsy group produced significantly lower scores on contextual visual memory whereas the intractable epilepsy group obtained significantly lower scores on visual-spatial memory compared to that of the children with ADHD. Additionally, the intractable epilepsy group demonstrated significantly lower verbal story memory than the ADHD and the controlled epilepsy groups. Despite obtaining significantly lower memory scores than the children with ADHD, the epilepsy groups still achieved average memory scores as well as an average learning slope and total word recall. These findings are inconsistent with previous research which has demonstrated children with epilepsy have significant memory difficulties. However, research in this area has been inconsistent where some studies were unable to demonstrate a relationship between epilepsy and memory difficulties. Our limited sample and small number of children with temporal lobe epilepsy likely contributed to these inconsistent findings and lack of memory weaknesses. It is difficult to determine whether the memory problems that children with epilepsy demonstrate are unique and go beyond their intellectual weaknesses. Therefore, intellectual functioning appears to have a predictive effect on children’s memory and is important to control in future studies.