title: Probing residual vestibular function with galvanic stimulation in vestibular loss patients.
abstract: BACKGROUND
  Galvanic vestibular stimulation (GVS) was used to probe the residual vestibular function in unilateral vestibular loss.
  
  
  METHODS
  39 control subjects, 60 patients areflexic to caloric tests, 21 patients with pre-operative acoustic neurinoma, and 26 patients with surgical deafferentation were tested with 4mA trapezoidal GVS. Horizontal slow phase velocity and vertical slow phase velocity components of the slow phase of induced nystagmus were recorded with videonystagmography.
  
  
  RESULTS
  All patients had lower horizontal slow phase velocity compared with intact subject. In caloric areflexic patients, the intact ear responded similarly to controls. The lesioned ear was less excitable but could be inhibited as in controls. In patients with acoustic neurinoma, the intact ear was normally excitable but less sensitive to inhibition. The lesioned ear, although not excitable, could be inhibited. In patients with surgical deafferentation, the intact ear could be barely excited and not inhibited. The lesioned ear could not be excited but slightly inhibited. These results fit well with previous data in animal models after unilateral vestibular loss.
  
  
  CONCLUSIONS
  Unilateral vestibular patients exhibit a progressive deterioration of the horizontal canal function, corresponding to 4 different patterns of GVS response. This study confirms that GVS is useful to probe evolution of the residual vestibular function in patients.
authors.affiliation: Centre d'Etude de la Sensorimotricité, Université Paris Descartes, Paris, France. benjamin_vailleau@yahoo.fr
authors.forename: Benjamin
authors.initials: B
authors.lastname: Vailleau
authors.forename: Céline
authors.initials: C
authors.lastname: Qu'hen
authors.forename: Pierre-Paul
authors.initials: PP
authors.lastname: Vidal
authors.forename: Catherine
authors.initials: C
authors.lastname: de Waele
mesh_terms: D000328:Adult; D000368:Aged; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000503:physiopathology*; D009759:Nystagmus, Pathologic / Q000503:physiopathology*; D015837:Vestibular Diseases / Q000503:physiopathology*; D014724:Vestibular Function Tests; D014722:Vestibule, Labyrinth / Q000503:physiopathology*