Sex and gender differences in memory in epilepsy: a systematic review and meta-analysis

Memory impairments are highly prevalent in patients with epilepsy, yet important gaps remain in the understanding of potential sex and gender differences. This systematic review and meta-analysis aim to synthesize the available evidence on sex and gender differences in memory functioning in adults and children with epilepsy, and to explore the relevance of the epilepsy type, the side of seizure focus, the hemispheric dominance for language, the educational level and the age group in these differences.

The study followed PRISMA guidelines and was registered in PROSPERO (CRD420251006928). Studies were retrieved from Web of Science, PubMed/MEDLINE, Embase, and Scopus.

The systematic search yielded 1,261 records, from which 32 studies were selected. Women scored higher than men in immediate verbal memory, both at baseline (g = 0.34; 95% CI = 0.23, 0.44; p < 0.0001) and after epilepsy surgery (g = 0.30; 95% CI = 0.15, 0.44; p < 0.0001). This advantage was also observed in delayed verbal memory, at baseline (g = 0.30; 95% CI = 0.19, 0.41; p < 0.0001) and after surgery (g = 0.25; 95% CI = 0.09, 0.41; p = 0.0018). In contrast, men outperformed women in immediate visual memory, both before (g = -0.13; 95% CI = -0.22, -0.03; p = 0.01) and after surgery (g = -0.17; 95% CI = -0.33, -0.01; p = 0.04). No significant differences were observed in working memory or delayed visual memory. Effect sizes favoring women in verbal memory were significantly smaller in studies including only patients with temporal lobe epilepsy compared to mixed epilepsy types. The effect size for postsurgical delayed verbal memory was moderated by the side of seizure focus: studies including a greater proportion of patients with left-hemisphere epilepsy showed poorer postsurgical delayed verbal memory. Hemispheric dominance for language, age, and educational level did not moderate sex-gender differences in memory.

These findings underscore the importance of incorporating sex and gender variables in neuropsychological assessment and intervention planning, offering evidence-based recommendations.