title: Presurgical language lateralization assessment by fMRI and dichotic listening of pediatric patients with intractable epilepsy.
abstract: OBJECTIVE
  The aim of this study was to evaluate the clinical use of a method to assess hemispheric language dominance in pediatric candidates for epilepsy surgery. The method is designed for patients but has previously been evaluated with healthy children.
  
  
  METHODS
  Nineteen patients, 8-18 years old, with intractable epilepsy and candidates for epilepsy surgery were assessed. The assessment consisted of two functional MRI protocols (fMRI) intended to target frontal and posterior language networks respectively, and a behavioral dichotic listening task (DL). Regional left/right indices for each fMRI task from the frontal, temporal and parietal lobe were calculated, and left/right indices of the DL task were calculated from responses of consonants and vowels, separately. A quantitative analysis of each patient's data set was done in two steps based on clearly specified criteria. First, fMRI data and DL data were analyzed separately to determine whether the result from each of these assessments were conclusive or not. Thereafter, the results from the individual assessments were combined to reach a final conclusion regarding hemispheric language dominance.
  
  
  RESULTS
  For 14 of the 19 subjects (74%) a conclusion was reached about their hemispheric language dominance. Nine subjects had a left-sided and five subjects had a right-sided hemispheric dominance. In three cases (16%) DL provided critical data to reach a conclusive result.
  
  
  CONCLUSIONS
  The success rate of conclusive language lateralization assessments in this study is comparable to reported rates on similar challenged pediatric populations. The results are promising but data from more patients than in the present study will be required to conclude on the clinical applicability of the method.
authors.affiliation: Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden ; Department of Speech and Language Pathology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Fritjof
authors.initials: F
authors.lastname: Norrelgen
authors.affiliation: Department of Neuroradiology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Lilja
authors.affiliation: Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Ingvar
authors.affiliation: Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Åmark
authors.affiliation: Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Peter
authors.initials: P
authors.lastname: Fransson
mesh_terms: D000293:Adolescent; D001931:Brain Mapping / Q000379:methods*; D002648:Child; D004827:Epilepsy / Q000601:surgery*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007802:Language; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011300:Preoperative Care
keywords: Children; Dichotic listening; Epilepsy surgery; Language lateralization; Neurodevelopmental disorders; fMRI