title: Resting-state functional connectivity predicts the strength of hemispheric lateralization for language processing in temporal lobe epilepsy and normals.
abstract: In temporal lobe epilepsy (TLE), determining the hemispheric specialization for language before surgery is critical to preserving a patient's cognitive abilities post-surgery. To date, the major techniques utilized are limited by the capacity of patients to efficiently realize the task. We determined whether resting-state functional connectivity (rsFC) is a reliable predictor of language hemispheric dominance in right and left TLE patients, relative to controls. We chose three subregions of the inferior frontal cortex (pars orbitalis, pars triangularis, and pars opercularis) as the seed regions. All participants performed both a verb generation task and a resting-state fMRI procedure. Based on the language task, we computed a laterality index (LI) for the resulting network. This revealed that 96% of the participants were left-hemisphere dominant, although there remained a large degree of variability in the strength of left lateralization. We tested whether LI correlated with rsFC values emerging from each seed. We revealed a set of regions that was specific to each group. Unique correlations involving the epileptic mesial temporal lobe were revealed for the right and left TLE patients, but not for the controls. Importantly, for both TLE groups, the rsFC emerging from a contralateral seed was the most predictive of LI. Overall, our data depict the broad patterns of rsFC that support strong versus weak left hemisphere language laterality. This project provides the first evidence that rsFC data may potentially be used on its own to verify the strength of hemispheric dominance for language in impaired or pathologic populations.
authors.affiliation: Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania; Department of Neurosurgery, Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Gaëlle E
authors.initials: GE
authors.lastname: Doucet
authors.forename: Dorian
authors.initials: D
authors.lastname: Pustina
authors.forename: Christopher
authors.initials: C
authors.lastname: Skidmore
authors.forename: Ashwini
authors.initials: A
authors.lastname: Sharan
authors.forename: Michael R
authors.initials: MR
authors.lastname: Sperling
authors.forename: Joseph I
authors.initials: JI
authors.lastname: Tracy
mesh_terms: D000328:Adult; D001921:Brain / Q000098:blood supply / Q000473:pathology*; D001931:Brain Mapping; D004569:Electroencephalography; D004833:Epilepsy, Temporal Lobe / Q000150:complications* / Q000473:pathology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007806:Language Disorders / Q000209:etiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D012044:Regression Analysis; D012146:Rest
chemical_list: D010100:Oxygen
keywords: hemispheric dominance; language; laterality index; resting-state functional connectivity; temporal lobe epilepsy