title: Retrospective Analysis of Interobserver Spatial Variability in the Localization of Broca's and Wernicke's Areas Using Three Different fMRI Language Paradigms.
abstract: OBJECTIVE
  To determine interobserver spatial variability in language area localization using three commonly employed language tasks.
  
  
  METHODS
  With institutional review board approval, 125 fMRI time series from 50 different clinical language cases were retrospectively reviewed by three blinded readers who selected 3-dimensional points representing the perceived center of Wernicke's and Broca's areas using three language tasks (semantic decision, SD; sentence comprehension, SC; and silent word generation, WG). Point dispersion values were then calculated using the perimeter of the 3-dimensional triangle defined by the three readers' selections.
  
  
  RESULTS
  After resolving interobserver laterality disagreements, there was no difference in spatial variability between the three tasks (P = .069). The SD task had the fewest interobserver laterality disagreements (P = .028) and the SC task had fewer failed localizations for Broca's area (P = .050) and Wernicke's area (P = .013).
  
  
  CONCLUSIONS
  While there were no differences between interobserver spatial variability in language area localization between the three tasks, language task choice impacts the accuracy of fMRI language area identification because tasks vary in their rates of interobserver laterality disagreements and failed localizations. A combination of tasks including one with low laterality disagreements (eg, SD) and one with few failed localizations (eg, SC) may offer the best combination.
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, MN.
authors.forename: David F
authors.initials: DF
authors.lastname: Black
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, MN.
authors.forename: David R
authors.initials: DR
authors.lastname: DeLone
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, MN.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Kaufmann
authors.affiliation: Department of Health Sciences Research, Mayo Clinic, Rochester, MN.
authors.forename: Patrick D
authors.initials: PD
authors.lastname: Fitz-Gibbon
authors.affiliation: Department of Health Sciences Research, Mayo Clinic, Rochester, MN.
authors.forename: Rickey E
authors.initials: RE
authors.lastname: Carter
authors.affiliation: Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN.
authors.forename: Mary M
authors.initials: MM
authors.lastname: Machulda
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, MN.
authors.forename: Kirk M
authors.initials: KM
authors.lastname: Welker
mesh_terms: D000293:Adolescent; D000328:Adult; D001931:Brain Mapping; D065711:Broca Area / Q000502:physiology*; D002648:Child; D005260:Female; D006801:Humans; D064795:Intraoperative Neurophysiological Monitoring / Q000379:methods*; D007802:Language; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D062211:Spatio-Temporal Analysis; D065813:Wernicke Area / Q000502:physiology*; D055815:Young Adult
keywords: Broca's area; Wernicke's area; fMRI; language lateralization