Abstracts

Rationale: Previous work has shown sex differences in episodic memory among children with epilepsy, with girls showing an advantage in verbal but not visual memory.  We sought to determine whether: 1) girls would also exhibit an advantage in aspects of semantic memory, specifically, naming, and 2) whether potential sex differences in naming might be related to laterality of seizure onset. Clinically, baseline strengths vs. weakness might carry different risks to naming with epilepsy surgery.  We administered recently developed, pediatric auditory and visual naming tests to boys and girls with left and right hemisphere epilepsy.  Based on adult studies and preliminary pediatric findings that show poorer auditory naming among left (dominant) than right hemisphere epilepsy patients, together with reported sex differences in verbal memory, we hypothesized that girls with left hemisphere epilepsy might exhibit stronger naming ability than boys with left hemisphere epilepsy. Methods: Participants were 63 children (mean age: 12.4 SD=2.1; mean FSIQ:  92.5 SD=12.1) with unilateral epilepsy (35 left, 17 girls; 28 right, 14 girls). The Visual Naming Test consisted of 36 color photographs of familiar items and the Auditory Naming Test consisted of 36 descriptions of familiar items.  Naming was assessed using both accuracy and time based measures: Number correct within 20 seconds (i.e., untimed), in < 2 seconds (i.e., automatic retrieval),  > 2 seconds (delayed responses), Tip-of-the-tongues (TOT, i.e., items named in 2-20 seconds or after 20 seconds following a phonemic cue) and a summary score combining two of these scores (Correct in 2 seconds – correct in 2-20 seconds).  Independent sample t-tests assessed potential naming and demographic differences between girls and boys in the left and right hemisphere groups. Results: Children with left and right hemisphere epilepsy were comparable in age (left: 11.6, SD=2.9; right 12.0, SD=2.6) and FSIQ (left: 93.6, SD=7.4; right: 90.1, SD=12.5).  Similar to prior findings, the left hemisphere group showed poorer naming scores than the right hemisphere group on the auditory naming task (P < .05).  Within the left and right hemisphere groups, there were no differences between girls and boys in age or FSIQ (all P > 0.05). However, within the left hemisphere group, girls had significantly higher scores than boys for all auditory and visual naming scores (all P < 0.03). By contrast, there were no sex differences in naming within the right hemisphere group (all P > 0.20). Conclusions: Analysis of sex differences in naming in children with unilateral epilepsy revealed significantly poorer naming among boys with left hemisphere epilepsy, yet no effect of sex on naming in children with right hemisphere epilepsy.  These results suggest that language might be less lateralized in girls, or that verbal function in boys might more vulnerable to the deleterious effect of seizures in the dominant hemisphere.  Results raise questions regarding relative vulnerability to surgical intervention among boys and girls with left hemisphere epilepsy. Funding: NIH Grant R01 NS 35140Ironshore did not fund or contribute to this research