Relationship between atypical language lateralization and cognition in pediatric patients with drug-resistant focal epilepsy: role of working memory.

INTRODUCTION

Language lateralization is typically characterized by left-hemisphere dominance; however, atypical language organization occurs more frequently in pediatric patients with drug-resistant focal epilepsy (DRFE), likely reflecting adaptive neuroplastic mechanisms. Because surgical treatment is the standard of care for DRFE, understanding the relationship between language organization and cognitive functioning is essential to minimize postoperative deficits during ongoing neurodevelopment. This study aimed to characterize language lateralization using functional magnetic resonance imaging (fMRI) and examine its association with cognitive performance in pediatric patients undergoing presurgical evaluation.

METHODS

A retrospective study included 17 children aged 6-16 years with drug-resistant epilepsy evaluated between 2022 and 2025 at a tertiary epilepsy center. All patients underwent fMRI language paradigms targeting receptive, expressive, and mixed functions, alongside comprehensive neuropsychological assessment using the Wechsler Intelligence Scale for Children-Fourth Edition and the Evaluación Neuropsicológica Infantil battery. Language lateralization was quantified using a lateralization index and classified as typical left, bilateral atypical, or right atypical. Descriptive statistics, Spearman correlation analyses, and simple linear regression models were performed.

RESULTS

Seventeen patients were analyzed (mean age 11.65 years). Cognitive performance was globally below age expectations, with most participants classified within borderline or very low intellectual ranges. Atypical language lateralization was observed in approximately 80% of cases, predominantly right-hemisphere organization. Bilateral atypical lateralization showed a tendency toward lower cognitive scores. Negative correlations were identified between lateralization index and working memory and visuospatial measures, although these associations lost significance after correction for multiple comparisons. Regression analysis indicated that language organization explained part of the variance in working memory performance.

DISCUSSION: Atypical language organization is highly prevalent in pediatric DRFE and may represent adaptive cortical reorganization. These findings highlight the relevance of fMRI language mapping for presurgical planning and understanding neurocognitive outcomes in developing brain.