title: Vertical display oscillation effects on forward vection and simulator sickness.
abstract: BACKGROUND
  The current study investigated the effects that vertical display oscillation had on the development of both vection and simulator sickness.
  
  
  METHODS
  There were 16 subjects who were exposed to optic flow displays which simulated either: 1) constant velocity forward self-motion (pure radial flow); or 2) combined constant velocity forward and vertically oscillating self-motion (radial flow with vertical oscillation at one of three frequencies: 1.8, 3.7, or 7.4 Hz). During each 10-min display exposure, subjects rated the strength of their vection and eight symptoms listed on the Subjective Symptoms of Motion Sickness (SSMS) scale at 2-min intervals. Subjects also completed the Simulator Sickness Questionnaire (SSQ) designed by Kennedy and colleagues before and after each trial, which generated a total SSQ score and three SSQ subscores (nausea, oculomotor symptoms, and disorientation).
  
  
  RESULTS
  Vertically oscillating displays (mean = 5.51; SD = 2.5) were found to produce significantly stronger vection ratings than non-oscillating displays (mean = 3.56; SD = 2.1). Vertically oscillating displays (mean = 58.18; SD = 32.2) were also found to produce significantly more severe sickness (as rated by total SSQ scores) than non-oscillating displays (mean = 29.67; SD = 24.7). Both vection and sickness symptoms increased in magnitude with prolonged exposure to optic flow.
  
  
  CONCLUSIONS
  Our findings appear to represent a special case in visual self-motion perception where high-frequency vertical oscillation both enhances vection and increases simulator sickness when it is incorporated into an optic flow display simulating constant velocity self-motion in depth.
authors.affiliation: School of Psychology, University of Wollongong, Wollongong, NSW 2522, Australia. Stephenp@uow.edu.au
authors.forename: Stephen
authors.initials: S
authors.lastname: Palmisano
authors.forename: Frederick
authors.initials: F
authors.lastname: Bonato
authors.forename: Andrea
authors.initials: A
authors.lastname: Bubka
authors.forename: John
authors.initials: J
authors.lastname: Folder
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology*; D006801:Humans; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D009041:Motion Sickness / Q000503:physiopathology*; D010775:Photic Stimulation; D012044:Regression Analysis; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires