title: Unilateral intracarotid amobarbital procedure for language lateralization.
abstract: OBJECTIVE
  The determination of language dominance as part of the presurgical workup of patients with pharmacoresistant epilepsies has experienced fundamental changes. With the introduction of noninvasive functional magnetic resonance imaging (fMRI), the number of patients receiving intracarotid amobarbital procedures (IAPs) for assessment of language dominance has decreased considerably. However, recent studies show that because of methodologic limitations of fMRI, IAP remains an important tool for language lateralization. The current study examines whether unilateral instead of bilateral IAP is an adequate way to apply IAP with reduced invasiveness.
  
  
  METHODS
  We retrospectively examine the predictive value of unilateral IAP for the results of bilateral IAP based on a sample of 75 patients with various types of language dominance. Target parameters are the prediction of the language-dominant hemisphere and the identification of patients with atypical language dominance. For language assessment based on unilateral IAP, we introduce the measure hemispheric language capacity (HLC).
  
  
  RESULTS
  Unilateral IAP performed on the side of intended surgery quantifies language capacity contralateral to the intended surgery. It detects atypical (bilateral or right) language dominance in the majority of patients. Experience with a separate series of 107 patients requiring presurgical language lateralization shows that in >80%, bilateral IAPs are redundant.
  
  
  CONCLUSIONS
  Unilateral IAP is principally sufficient for language lateralization in the presurgical evaluation of patients with pharmacoresistant epilepsies. Necessity of bilateral IAP is restricted to few indications (e.g., callosotomy). In times of noninvasive language lateralization, we propose unilateral IAP as the method of choice for the verification of doubtful (bilateral) fMRI activation patterns.
authors.affiliation: Department of Epileptology, Universiy of Bonn, Bonn, Germany. j.wellmer@gmx.de
authors.forename: Jörg
authors.initials: J
authors.lastname: Wellmer
authors.forename: Guillen
authors.initials: G
authors.lastname: Fernández
authors.forename: Detlef B
authors.initials: DB
authors.lastname: Linke
authors.forename: Horst
authors.initials: H
authors.lastname: Urbach
authors.forename: Christian E
authors.initials: CE
authors.lastname: Elger
authors.forename: Martin
authors.initials: M
authors.lastname: Kurthen
mesh_terms: D000293:Adolescent; D000328:Adult; D000654:Amobarbital / Q000008:administration & dosage / Q000494:pharmacology; D001931:Brain Mapping / Q000379:methods; D002343:Carotid Artery, Internal; D002540:Cerebral Cortex / Q000187:drug effects* / Q000502:physiology* / Q000503:physiopathology; D002648:Child; D004827:Epilepsy / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery; D005260:Female; D007839:Functional Laterality / Q000187:drug effects* / Q000502:physiology*; D006801:Humans; D007269:Injections, Intra-Arterial; D007802:Language; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care
chemical_list: D000654:Amobarbital