title: Role of functional MR in determining language dominance in epilepsy and nonepilepsy populations: a Bayesian analysis.
abstract: OBJECTIVE
  To determine the role of functional magnetic resonance (MR) imaging in assessing hemispheric language dominance in epilepsy and nonepilepsy populations.
  
  
  METHODS
  A Bayesian analysis study was performed. The study was based on data from the published literature; thus, institutional review board approval was not required. The literature was reviewed to obtain pretest probabilities and likelihood ratios, which were analyzed to determine the posttest probability of language dominance by using functional MR imaging. Pretest probabilities of different hand dominances in epilepsy and nonepilepsy populations were obtained from the largest studies available in the literature. Likelihood ratios were derived from the sensitivity and specificity of functional MR imaging by using electrocortical stimulation (ECS) and the Wada test as reference standards.
  
  
  RESULTS
  Likelihood ratios for functional MR in determining language dominance were 9.3 and 12.3 with ECS and the Wada test as reference standards, respectively. Use of functional MR increased the final posttest probabilities of hemispheric language dominance in epilepsy and nonepilepsy populations. In the nonepilepsy population, regardless of hand dominance, there was very high posttest probability (>or=96%) of a correlation between functional MR hemisphere activation and definite left-hemisphere language dominance. In the epilepsy population with right-hand dominance or ambidexterity, there was very high posttest probability (>or=95%) of a correlation between functional MR hemisphere activation and definite left-hemisphere language dominance. In the left-handed nonepileptic subjects, there was high posttest probability (81%-83%) of a correlation between functional MR hemisphere activation and definite right-hemisphere language dominance. In the left-handed epilepsy population, there was high posttest probability (80%-97%) of a correlation between functional MR hemisphere activation and definite left-hemisphere language dominance. In the epilepsy population with ambidexterity, there was high posttest probability (80%-87%) of correlations between functional MR hemisphere activation and both definite right-hemisphere and bilateral language dominance.
  
  
  CONCLUSIONS
  Use of functional MR increases importantly the posttest probabilities of hemispheric language dominance in multiple subgroups of individuals with and without epilepsy.
authors.affiliation: Department of Radiology and Health Outcomes, Policy and Economics Center, Miami Children's Hospital, 3100 SW 62nd Ave, Miami, FL 33155, USA. smedina@post.harvard.edu
authors.forename: L Santiago
authors.initials: LS
authors.lastname: Medina
authors.forename: Byron
authors.initials: B
authors.lastname: Bernal
authors.forename: Jeniffer
authors.initials: J
authors.lastname: Ruiz
mesh_terms: D001499:Bayes Theorem; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods*; D002986:Clinical Trials as Topic / Q000706:statistics & numerical data; D004292:Dominance, Cerebral; D004827:Epilepsy / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007802:Language; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity