title: Off-vertical axis rotation of the visual field and nauseogenicity.
abstract: BACKGROUND
  Off-vertical axis rotation (OVAR) causes motion sickness which increases with angle of tilt and is most provocative around 0.2 Hz. The aim was to determine the tilt angle and frequency characteristics for visual OVAR, which is also known to be nauseogenic.
  
  
  METHODS
  A computerized scene, as seen by a pilot at moderate altitude, rotated at different frequencies about an axis which could tilt as during OVAR. A concurrent visual detection task controlled attention. Exposures were for 10 min or until nausea developed. There were four experiments: Frequency tuning-visual motion at 0.05, 0.2, and 0.8 Hz, all at 18 degrees tilt of the axis of rotation (N = 14); gross visual tilt tuning-visual motion at 0, 45, and 90 degrees of tilt at 0.2 Hz (N = 12); fine visual tilt tuning -- 18, 36, 54, and 72 degrees tilts at 0.2 Hz (N = 24); and whole-body tilt of the participant at 0, 45, and 90 degrees, viewing rotation about a vertical axis at 0.2 Hz (N = 12).
  
  
  RESULTS
  Nauseogenicity was significantly greater at 0.2 Hz than at lower or higher frequencies. Visual tilts 18 degrees to circa 45 degrees were significantly more nauseogenic. No differences were found between whole-body tilts.
  
  
  CONCLUSIONS
  Nauseogenicity of visual OVAR peaks around 0.2 Hz, and increases with stimulus strength up to circa 45 degrees tilt, similar to real motion. With higher tilt angles, decreasing nauseogenicity suggests that the visual impact is partially quarantined because the motion would appear patently absurd and not a sensory conflict. Whole-body tilt may have failed to modulate nauseogenicity because of overriding somatosensory cues to Earth vertical.
authors.affiliation: Department of Psychology, University of Westminster, 309 Regent Street, London W1B 2UW, UK. goldinj@westminster.ac.uk
authors.forename: John F
authors.initials: JF
authors.lastname: Golding
authors.forename: Smitha
authors.initials: S
authors.lastname: Arun
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Wortley
authors.forename: Kahina
authors.initials: K
authors.lastname: Wotton-Hamrioui
authors.forename: Sian
authors.initials: S
authors.lastname: Cousins
authors.forename: Michael A
authors.initials: MA
authors.lastname: Gresty
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D009041:Motion Sickness / Q000503:physiopathology*; D011597:Psychomotor Performance / Q000502:physiology; D012399:Rotation / Q000009:adverse effects; D014796:Visual Perception / Q000502:physiology; D055815:Young Adult