Motion sickness, virtual reality and postural Stability.

University of Minnesota Ph.D. dissertation. December 2009. Major: Kinesiology. Advisor: Thomas A. Stoffregen, PhD. 1 computer file (PDF); viii, 87 pages.Motion sickness has been anecdotally reported to occur in the video game community. No confirmation of these reports has been documented by research studies in a laboratory setting. The present investigation was motivated, in part, by the lack of scientific documentation of motion sickness occurrence among video game users. Although some published work (Cobb, 1999; Cobb and Nichols, 1998) showed that users of video game tend to develop some symptoms of motion sickness, there was no clear indication whether these subjects in fact experienced motion sickness. In this work, I argue that this uncertainty can be answered by simply asking the subjects whether they experience motion sickness throughout their virtual reality exposure, instead of only measuring the variation in terms of sickness symptoms score. It is also important to stress that the published studies on motion sickness and video games mainly use simplified laboratory developed video games, rather than using the commercially available console video games. In addition, motion sickness is studied in laboratory settings rather than in more realistic conditions. Therefore, this work is intended to document the existence of motion sickness, in a realistic environment. I varied the game that participants played, their posture during game play (standing vs. sitting), and the technology through which games were presented (video monitor vs. head-mounted display). In addition, I sought to evaluate the postural instability theory of motion sickness in the context of video game use. I measured body motion during game play, and showed that motion sickness was preceded by changes in both the magnitude and dynamics of body movement. In this work, participants played standard console video games using an Xbox game system. The series of experiments conducted were published in two peer review articles. The first paper "Motion Sickness, Console Video Games, and Head-Mounted Displays" evaluated the nauseogenic properties of commercial console video games when presented through a head-mounted display. The work published in this paper was aimed at 1) determining whether commercial console video games might be associated with motion sickness, 2) understanding some of the factors that my influence the incidence of motion sickness when commercial console video games are presented via an Head Mounted Display as well as conventional video monitor, and 3) documenting participants' body movement during game play and to use these data to evaluate a prediction of the postural instability theory of motion sickness (Riccio & Stoffregen, 1991). Participants played standard console video games using Xbox game system. The game type (two Xbox games) and postural configuration (standing vs. sitting) were varied. Subjects played for up to 50 minutes and were asked to discontinue if they experience any symptoms of motion sickness. The results showed that sickness occurred in all conditions, but it was more common during standing. There was statistically significant difference in head motion between sick and well participants before the onset of motion sickness during seated play. The findings indicate that commercial console video game systems can be linked to motion sickness occurrence when presented via a head-mounted display and support the hypothesis that motion sickness is preceded by instability in the control of seated posture. Although the results point at a relationship between motion sickness and video game when the game is played using an HMD, addition work was needed to test this relationship in a more realistic circumstances. In the second paper, "Motion Sickness and Postural Sway in Console Video Games", the work was aimed at testing the hypothesis that 1) participants might develop motion sickness while playing "off-the-shelf" console video games and 2) postural motion would differ between sick and well participants, prior to the onset and motion sickness. Participants in this sequence of experiments played a game continuously for up to 50 minutes while standing or sitting. The distance to the display screen was varied. As result, motion sickness was observed across conditions. It ranged from 42% to 56%. During game play, head and torso motion differed between sick and well participants prior to the onset of subjective of motion sickness. The results from this work indicated that console video game carry significant risk of motion sickness, even when displayed on conventional video monitor. In conclusion, the present work has successfully documented the anecdotal relationship between motion sickness and video games. Sickness occurred in all conditions. The results indicate that commercial console video game systems can induce motion sickness when presented via a head-mounted display, and via conventional video monitor. The results support the hypothesis that motion sickness is preceded by instability in the control of seated posture