AUTHOR=Kuchukhidze Giorgi , Siedentopf Christian , Unterberger Iris , Koppelstaetter Florian , Kronbichler Martin , Zamarian Laura , Haberlandt Edda , Ischebeck Anja , Delazer Margarete , Felber Stephan , Trinka Eugen 

TITLE=Language Dominance in Patients With Malformations of Cortical Development and Epilepsy

JOURNAL=Frontiers in Neurology

VOLUME=Volume 10 - 2019

YEAR=2019

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2019.01209

DOI=10.3389/fneur.2019.01209

ISSN=1664-2295

ABSTRACT=Objective: Language function may be reorganized in patients with malformations of cortical development (MCD). This prospective cohort study aimed assessing language dominance in a large group of patients with MCD and epilepsy by use of functional MRI (fMRI). 
Methods: Sixty-eight patients (40 women) aged 10 - 73 years (median 28.0; interquartile range 22-41) with MCD and epilepsy underwent 1.5 Tesla MRI and fMRI (word generation task). Single-subject image analysis was performed with statistical parametric mapping (SPM12). Language lateralization indices (LIs) were defined for statistically significantly activated voxels in Broca's and Wernicke's areas using the formula: LI = (VL -VR)/(VL + VR) x100, where VL  and VR were sets of activated voxels on the left and on the right respectively. Language laterality was considered typical if LI was between +20 and +100 or atypical if LI was between +19 and -100.
Results: FMRI signal was elicited in 55/68 (81%) patients. In 18/55 (33%) patients, language dominance was typical and in 37/55 (67%) - atypical (in 68% – right hemispheric; in 32% – bilateral). There was a tendency of occurrence of an atypical language dominance in left-handers and in patients with left-hemispheric and bilateral MCD vs. right-hemispheric MCD as well as in those with left-hemispheric and bilateral vs. right-hemispheric seizure foci.  Language dominance was not influenced by other electro-clinical and imaging features.
Conclusions: In this prospective study on a large group of patients with MCD and epilepsy, about two-thirds had atypical language dominance. These results may contribute to assessing risks of post-surgical language deficits and could assist in planning of "cortical mapping" with intracranial electrodes in patients who undergo pre-surgical assessment.