title: "Virtual" lesioning of the human oropharyngeal motor cortex: a videofluoroscopic study.
abstract: OBJECTIVE
  To use focal cortical inhibition and create a "virtual" lesion in the oropharyngeal motor cortex in healthy subjects to determine whether this provokes swallowing dysfunction.
  
  
  METHODS
  Intervention study: before and after cortical stimulation.
  
  
  METHODS
  Tertiary care center.
  
  
  METHODS
  Healthy adult volunteers (N=9; age range, 21-44y) participated in the study.
  
  
  METHODS
  Active or sham 1-Hz repetitive transcranial magnetic stimulation (rTMS) over the cortical sites in each hemisphere evoking the largest mylohyoid motor-evoked potentials (mMEPs) to single pulse transcranial magnetic stimulation.
  
  
  METHODS
  Videofluoroscopic assessment was performed before and 5, 30, and 60 minutes after rTMS.
  
  
  RESULTS
  The motor threshold was 83%±10% for the hemisphere with the larger mMEP (dominant) and 92%±9% for the hemisphere with the smaller mMEP (nondominant). When rTMS was performed over the dominant hemisphere, there was a decrease in oral transit time (P=.05), an increase in swallow reaction time (P=.0001), but no change of pharyngeal transit time or laryngeal closure duration. When rTMS was performed on the nondominant hemisphere, there was also a decrease in oral transit time (P=.05), but no change in any of the other swallowing measures. Neither active intervention produced any signs of aspiration or penetration. Sham stimulation had no effect.
  
  
  CONCLUSIONS
  Inhibiting the human oropharyngeal motor cortex using rTMS transiently modifies swallowing behavior in a way reminiscent to that seen in stroke patients.
authors.affiliation: Department of Physiology, Rouen University Hospital, Rouen, France. eric.verin@chu-rouen.fr
authors.forename: Eric
authors.initials: E
authors.lastname: Verin
authors.forename: Emilia
authors.initials: E
authors.lastname: Michou
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Leroi
authors.forename: Shaheen
authors.initials: S
authors.lastname: Hamdy
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Marie
mesh_terms: D000328:Adult; D003680:Deglutition Disorders / Q000503:physiopathology*; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D008297:Male; D008954:Models, Biological; D009044:Motor Cortex / Q000503:physiopathology; D026741:Physical Therapy Modalities; D011930:Reaction Time; D020521:Stroke / Q000503:physiopathology*; D050781:Transcranial Magnetic Stimulation / Q000379:methods*; D014741:Video Recording