title: FMRI lateralization of expressive language in children with cerebral lesions.
abstract: OBJECTIVE
  Lateralization of language function is crucial to the planning of surgery in children with frontal or temporal lobe lesions. We examined the utility of functional magnetic resonance imaging (fMRI) as a determinant of lateralization of expressive language in children with cerebral lesions.
  
  
  METHODS
  fMRI language lateralization was attempted in 35 children (29 with epilepsy) aged 8-18 years with frontal or temporal lobe lesions (28 left hemisphere, five right hemisphere, two bilateral). Axial and coronal fMRI scans through the frontal and temporal lobes were acquired at 1.5 Tesla by using a block-design, covert word-generation paradigm. Activation maps were lateralized by blinded visual inspection and quantitative asymmetry indices (hemispheric and inferior frontal regions of interest, at p<0.001 uncorrected and p<0.05 Bonferroni corrected).
  
  
  RESULTS
  Thirty children showed significant activation in the inferior frontal gyrus. Lateralization by visual inspection was left in 21, right in six, and bilateral in three, and concordant with hemispheric and inferior frontal quantitative lateralization in 93% of cases. Developmental tumors and dysplasias involving the inferior left frontal lobe had activation overlying or abutting the lesion in five of six cases. fMRI language lateralization was corroborated in six children by frontal cortex stimulation or intracarotid amytal testing and indirectly supported by aphasiology in a further six cases. In two children, fMRI language lateralization was bilateral, and corroborative methods of language lateralization were left. Neither lesion lateralization, patient handedness, nor developmental versus acquired nature of the lesion was associated with language lateralization. Involvement of the left inferior or middle frontal gyri increased the likelihood of atypical language lateralization.
  
  
  CONCLUSIONS
  fMRI lateralizes language in children with cerebral lesions, although caution is needed in interpretation of individual results.
authors.affiliation: Brain Research Institute, Heidelberg, Victoria, Australia.
authors.forename: Dianne P
authors.initials: DP
authors.lastname: Anderson
authors.forename: A Simon
authors.initials: AS
authors.lastname: Harvey
authors.forename: Michael M
authors.initials: MM
authors.lastname: Saling
authors.forename: Vicki
authors.initials: V
authors.lastname: Anderson
authors.forename: Michael
authors.initials: M
authors.lastname: Kean
authors.forename: David F
authors.initials: DF
authors.lastname: Abbott
authors.forename: R Mark
authors.initials: RM
authors.lastname: Wellard
authors.forename: Graeme D
authors.initials: GD
authors.lastname: Jackson
mesh_terms: D000293:Adolescent; D000654:Amobarbital / Q000494:pharmacology; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D002648:Child; D004827:Epilepsy / Q000175:diagnosis* / Q000601:surgery*; D017034:Epilepsy, Frontal Lobe / Q000175:diagnosis / Q000503:physiopathology; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis / Q000503:physiopathology; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology / Q000601:surgery; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007802:Language; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D011300:Preoperative Care / Q000379:methods; D013702:Temporal Lobe / Q000503:physiopathology / Q000601:surgery
chemical_list: D000654:Amobarbital