title: Speech mapping using depth electrodes: The "electric Wada".
abstract: OBJECTIVE
  The Wada test is the gold standard for identification of the side of speech dominance but is associated with risk of angiography and requires patient cooperation. We report a method to verify speech laterality using implanted electrodes in patients undergoing stereo-encephalography (SEEG).
  
  
  METHODS
  Four pediatric patients with frontal lobe drug-resistant epilepsy underwent implantation of multiple SEEG electrodes using framed stereotaxy to identify the epileptogenic zone, including electrodes placed bilaterally into the pars opercularis of each inferior frontal gyrus from a superior parasagittal entry point. Biphasic stimulation at 50Hz, 0.3ms pulse width, up to 10mA was administered to distal contacts during a reading task.
  
  
  RESULTS
  Speech arrest upon stimulation was obtained when stimulating distal contacts in the inferior frontal gyrus on one side with no effect on the contralateral side, establishing language laterality in every patient. This information was used to plan subsequent surgical treatment. There were no adverse events of implantation or stimulation.
  
  
  CONCLUSIONS
  Brain mapping using SEEG electrodes is feasible and can be used to lateralize speech dominance. In cases of frontal lobe epilepsy in which electrodes will be implanted bilaterally for recording of ictal activity, this technique may make the Wada test unnecessary.
authors.affiliation: The Neurological Institute, University Hospital Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States.
authors.forename: Fernando
authors.initials: F
authors.lastname: Alonso
authors.affiliation: The Neurological Institute, University Hospital Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Sweet
authors.affiliation: The Neurological Institute, University Hospital Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States. Electronic address: Jonathan.Miller@UHHospitals.org.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Miller
mesh_terms: D000293:Adolescent; D001931:Brain Mapping / Q000295:instrumentation / Q000379:methods*; D002648:Child; D000069279:Drug Resistant Epilepsy / Q000175:diagnosis / Q000601:surgery*; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000295:instrumentation / Q000379:methods*; D005260:Female; D005625:Frontal Lobe / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D013060:Speech / Q000502:physiology*; D013238:Stereotaxic Techniques / Q000295:instrumentation
keywords: Brain mapping; SEEG; Speech dominance; Stereo-encephalography; Wada test