Predictors of atypical language lateralization in focal epilepsy: A mega-analysis of fMRI evidence

Authors

Freya Prentice, Developmental Neurosciences Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK.
Lara Chehabeddine, Developmental Neurosciences Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK.
Maria Helena Eriksson, Developmental Neurosciences Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK.
Jennifer Murphy, School of Psychology, University of Surrey, Guildford, UK.
Leigh N. Sepeta, Center for Neuroscience Research, Children's National Hospital, George Washington University, Washington, District of Columbia, USA.
William D. Gaillard, Center for Neuroscience Research, Children's National Hospital, George Washington University, Washington, District of Columbia, USA.
Madison M. Berl, Division of Neuropsychology, Children's National Hospital, Washington, District of Columbia, USA.
Frédérique Liégeois, Developmental Neurosciences Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK.
Torsten Baldeweg, Developmental Neurosciences Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK.

Document Type

Journal Article

Publication Date

5-5-2025

Journal

Epilepsia

DOI

10.1111/epi.18422

Keywords

epilepsy surgery; fMRI; language lateralization; language plasticity

Abstract

OBJECTIVE: To identify predictors of language lateralization derived from functional magnetic resonance imaging (fMRI) in children and adults with left- and right-sided focal epilepsy. METHODS: We conducted a mega-analysis of data from 914 individuals from 24 samples. We used multilevel models to identify predictors of language lateralization in left and right hemisphere epilepsy groups. We assigned each participant a clinical predictor score to explore whether there was a cumulative influence of predictors on increasing atypical language lateralization. RESULTS: Left hemisphere epilepsy was a predictor of greater atypical language lateralization in the combined sample. Additional predictors of atypical language lateralization included left/ambidextrous handedness in both the left and right hemisphere groups, and longer duration of epilepsy, frontal lobe involvement, and history of a stroke or other precipitating injury in the left hemisphere group only. There was a cumulative effect of predictors in the left hemisphere groups. Eighty percent of individuals with four or more predictors had atypical language lateralization, compared to 19% of individuals with no predictors, other than left hemisphere epilepsy. SIGNIFICANCE: Consistent with theories of language plasticity, we demonstrated a robust effect of early acquired left hemisphere injury on language lateralization. There was also a subtle effect of duration of epilepsy, perhaps reflecting increasing bilaterality with age in adulthood. The association between left/ambidextrous handedness and atypical language lateralization in the left and right hemisphere groups likely reflects both genetic and epilepsy-associated effects. The total number of predictors identified for an individual could serve as an indication for presurgical language fMRI, when surgical management is considered.

APA Citation

Prentice, Freya; Chehabeddine, Lara; Eriksson, Maria Helena; Murphy, Jennifer; Sepeta, Leigh N.; Gaillard, William D.; Berl, Madison M.; Liégeois, Frédérique; and Baldeweg, Torsten, "Predictors of atypical language lateralization in focal epilepsy: A mega-analysis of fMRI evidence" (2025). GW Authored Works. Paper 7303.
https://hsrc.himmelfarb.gwu.edu/gwhpubs/7303

Department

Neurology