Functional Connectivity As a Tool to Ascertain Language Localization in a Group of Children with Intractable Epilepsy

Introduction:We investigated the relationship between lateralization indices based on the of Brodmann areas (BA) connectivity and language fMRI paradigms in a group of children with intractable epilepsy. Methodology:Intra-hemispheric ROI-to-ROI connectivity was assessed in 36 epileptic children (24 females) mean age 15.3 years, utilizing resting-state fMRI.Left vs right asymmetries were investigated between (1) BA pairs (pair-wise connectivity: PWC); (2) BA modules (global BA module connectivity: GBA); and (3) cerebral hemispheres (global hemispheric connectivity: GHC).Connectivity strength was graded in T scores (Z normalized values).Lateralization Index (LI) scores based on T values were obtained in all three assessments.Only LI with 2 SD above the mean were considered as significant lateralized pairs.Additionally, simple algebraic difference between left and right T values were obtained (TDIF).Results: Connectivity-related LI of significant pairs (predictors) were regressed against Language-fMRI-based LIs.Sensitivity and specificity of significant predictors were found.Interactions with demographics, seizure features, and neuropsychological scores were also performed.Comparisons between T value-groups (per side and per BA) were performed utilizing double-sided T-tests.The null hypothesis was rejected for P < 0.05. Conclusion:There was no statistical difference between left and right GHC strength (P = 0.57), or by GBA-LI (LI = 0.0004).6 BA pairs showed significant PWC-LI (> 0.424): BA9-BA19 (0.429); BA22-BA46 (-0.529);BA39-BA46 (0.679); BA39-BA42 (0.534); BA41-BA45 (-0.496); and BA42-BA46 (0.464). 5 BA pairs showed significant PWC-TDIF (> 3.32): BA9-BA47 (4.19); BA9-BA19 (3.81); BA21-BA45 (3.49); BA39-BA45 (3.90); and BA40-BA44 (-3.61).BA39-BA46 had a sensitivity of 80% for language lateralization of both language domains.