Brightness and contrast do not affect visually induced motion sickness in a passively-flown fixed-base flight simulator

•Passively flying in a flight simulator elicits VIMS and increased postural sway.•All conditions produced significant VIMS compared with baseline.•No significant VIMS differences were found between conditions.•Increased sway was prevented in the high brightness, low contrast condition.

BackgroundVisually Induced Motion Sickness (VIMS) or simulator sickness is often elicited by a visual stimulus that lacks the appropriate vestibular or proprioceptive feedback. In this study, we chose to investigate the effects of brightness and contrast of the visual scene on VIMS.HypothesisWe hypothesized that visual environments differing in brightness or contrast would differentially induce VIMS. The symptoms of VIMS should be most severe for the combination of high brightness and high contrast and conversely lowest for the low brightness and low contrast condition.Methods33 healthy subjects were tested in a fixed-base flight simulator. Each subject flew in four consecutive but counterbalanced conditions during one large experimental session. The four conditions consisted of identical recorded flight paths, differing only in brightness and contrast in a fully crossed design. VIMS was assessed with the Simulator Sickness Questionnaire and the Fast Motion Sickness scale administered during and after each condition. Postural Sway (PS) was measured after each condition.ResultsAll four brightness and contrast conditions were found to be effective in that they increased PS and elicited moderate VIMS. However, there were no main or interaction effects for brightness or contrast.ConclusionsOur findings suggest that brightness and contrast do not modulate the induction of VIMS. This conclusion may be limited to moderately provocative stimuli.