Abstracts

Rationale: A number of studies have suggested that females have a relative advantage for verbal memory as compared to males in normal populations, although this finding has not been universal. This has also been demonstrated in several studies of adults with temporal lobe epilepsy. A recent report sought to determine if this finding also extends to children with intractable epilepsy. Boys and girls were compared on their performance across several memory measures including delayed story recall, immediate and delayed word-list learning, delayed complex design recall, and delayed face recognition (Smith ML, Elliott I, & Naguiat A, 2009). These authors found that girls demonstrated an advantage over boys on delayed recall of stories and on the learning phase of the word list. No other memory differences were observed between the groups. The current study sought to replicate this research in an independent sample of children with left temporal lobe epilepsy. Methods: 22 children (10 boys, 12 girls) who were candidates for left temporal lobe resection underwent neuropsychological evaluation prior to undergoing epilepsy surgery. Children ranged in age from 6 to 15 years (mean=11.14 (2.9)) The groups were not different in terms of age, age at seizure onset or duration of epilepsy. The Girls group was slightly older than the Boys group (avg. 11.75 vs. 10.4), but not significantly so. Memory performance of Boys and Girls was compared using select subtests from the Children s Memory Scale (i.e., story memory, word pair learning, spatial learning, and facial recognition). FSIQ for the Girls group was higher and had a medium effect size (d=.58). Given the relatively small sample size in each of the two groups, effect sizes (Cohen d) were used to examine group differences rather than relying on traditional significance testing (i.e., p values). Moderate to large effect sizes (i.e., .5 and higher) were considered meaningful. Results: Girls demonstrated better memory performance than Boys on all delayed memory measures (d range = .57 to .71) with the exception of facial recognition (d range = .19 to .48). Girls also demonstrated superior immediate recall of stories (d = .628) as compared to Boys. No other significant differences were observed between the groups on immediate memory tasks (d range =.129 to .312). Conclusions: Consistent with the findings of Smith et al. (2009), girls in the current study obtained higher scores than boys on a delayed story recall measure and did not demonstrate any significant differences in delayed facial recognition. The current study extends those findings by demonstrating differences in memory performance on measures of word pair recall and delayed recall of spatial locations in a sample of children with intractable left temporal lobe epilepsy. The reason for the observed sex differences is unclear, but may be a reflection of a difference in neurocognitive plasticity proposed by Trenerry et al (1995). Future research will seek to determine whether these differences are also observed post-operatively, and whether sex confers differential risk for memory outcome following temporal lobe resection.