title: Subjective visual vertical and horizontal: effect of the preset angle.
abstract: OBJECTIVE
  (1) To study the subjective visual vertical (SVV) and subjective visual horizontal (SVH) in patients with long-standing unilateral peripheral vestibular dysfunction (PVD) and unilateral Ménière's disease (MD) compared with controls. (2) To study the relationship between the direction of deviation of the linear marker (preset angle) and measures of SVV and SVH values.
  
  
  METHODS
  Prospective case-control study.
  
  
  METHODS
  Outpatient clinic in a tertiary neuro-otology department.
  
  
  METHODS
  Seventeen healthy volunteers (mean age, 35.5 years), 9 patients with PVD (mean age, 43.1 years), and 10 patients with MD (mean age, 50.7 years) were included in the analysis.
  
  
  METHODS
  All subjects had a detailed neuro-otological evaluation. Twelve replicate readings of SVV and SVH were taken for each subject, with random preset angles, 6 in the clockwise and 6 in the counterclockwise direction.
  
  
  METHODS
  The SVV and SVH values were correlated with clinical features and the direction of the preset angle.
  
  
  RESULTS
  The 2 subjects with PVD who had abnormal mean SVV and SVH values had symptoms of dysequilibrium and otolithic involvement. The 5 patients in the MD group who had abnormal mean SVV and SVH values had either recent acute vertiginous attacks or total canal paresis on the affected side. A previously unreported finding, to our knowledge, is that the SVV value depends on the direction of the preset angle in all subject groups, more so in the PVD and MD groups compared with controls. The SVV is inclined toward the direction of the preset angle. A weaker relation is seen between the SVH and preset angle.
  
  
  CONCLUSIONS
  The preset angle should be considered when comparing SVV and SVH values.
authors.affiliation: Department of Audiovestibular Medicine, Royal National Throat, Nose, and Ear Hospital, London, England.
authors.forename: Waheeda
authors.initials: W
authors.lastname: Pagarkar
authors.forename: Doris-Eva
authors.initials: DE
authors.lastname: Bamiou
authors.forename: Deborah
authors.initials: D
authors.lastname: Ridout
authors.forename: Linda M
authors.initials: LM
authors.lastname: Luxon
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008575:Meniere Disease / Q000503:physiopathology*; D008875:Middle Aged; D010364:Pattern Recognition, Visual; D010865:Pilot Projects; D011237:Predictive Value of Tests; D011446:Prospective Studies; D014724:Vestibular Function Tests; D014722:Vestibule, Labyrinth / Q000503:physiopathology; D000160:Vestibulocochlear Nerve Diseases / Q000503:physiopathology*; D014796:Visual Perception / Q000502:physiology*