title: Intrasubject reproducibility of presurgical language lateralization and mapping using fMRI.
abstract: BACKGROUND
  fMRI is becoming a standard tool for the presurgical lateralization and mapping of brain areas involved in language processing. However, its within-subject reproducibility has yet to be fully explored.
  
  
  OBJECTIVE
  To evaluate within-test and test-retest reliability of language fMRI in consecutive patients undergoing evaluation for epilepsy surgery.
  
  
  METHODS
  Thirty-four unselected patients were investigated once (within-test reliability) and 12 patients twice (test-retest reliability). The imaging series consisted of an alternating 25-second synonym judgment condition with a 25-second letter-matching condition repeated 15 times. Reproducibility of activation maps of the first and second half of session 1 or activation maps of sessions 1 and 2 was evaluated by comparing one global and three regional lateralization indexes (Broca's area, remaining prefrontal cortex, temporoparietal area) and on a voxel-by-voxel basis (intraclass correlation coefficient, percentage overlap, correlation of t-values).
  
  
  RESULTS
  Global and regional language lateralization was achieved with high reliability within and across sessions. Reproducibility was evenly distributed across both hemispheres but not within each hemisphere. Frontal activations were more reliable than temporoparietal ones. Depending on the statistical threshold chosen, the voxel-by-voxel analysis revealed a mean overlap of activations derived from the first and second investigation of up to 48.9%.
  
  
  CONCLUSIONS
  Language fMRI proved sufficiently reliable for the determination of global and regional lateralization of language representation in individual unselected patients with epilepsy.
authors.affiliation: Department of Epileptology, University of Bonn, Germany. guillen.fernandez@fcdonders.kun.nl
authors.forename: G
authors.initials: G
authors.lastname: Fernández
authors.forename: K
authors.initials: K
authors.lastname: Specht
authors.forename: S
authors.initials: S
authors.lastname: Weis
authors.forename: I
authors.initials: I
authors.lastname: Tendolkar
authors.forename: M
authors.initials: M
authors.lastname: Reuber
authors.forename: J
authors.initials: J
authors.lastname: Fell
authors.forename: P
authors.initials: P
authors.lastname: Klaver
authors.forename: J
authors.initials: J
authors.lastname: Ruhlmann
authors.forename: J
authors.initials: J
authors.lastname: Reul
authors.forename: C E
authors.initials: CE
authors.lastname: Elger
mesh_terms: D000293:Adolescent; D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D004292:Dominance, Cerebral; D004828:Epilepsies, Partial / Q000503:physiopathology / Q000601:surgery; D005260:Female; D006801:Humans; D007802:Language; D007806:Language Disorders / Q000517:prevention & control; D007807:Language Tests; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000517:prevention & control; D011300:Preoperative Care; D015203:Reproducibility of Results; D012660:Semantics