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Objective: We evaluated the nauseogenic properties of commercial console video games (i.e., games that are sold to the public) when presented through a head-mounted display. Background: Anecdotal reports suggest that motion sickness may occur among players of contemporary commercial console video games. Methods: Participants played standard console video games using an Xbox game system. We varied the participants' posture (standing vs. sitting) and the game (two Xbox games). Participants played for up to 50 min and were asked to discontinue if they experienced any symptoms of motion sickness. Results: Sickness occurred in all conditions, but it was more common during standing. During seated play there were significant differences in head motion between sick and well participants before the onset of motion sickness. Conclusion: The results indicate that commercial console video game systems can induce motion sickness when presented via a head-mounted display and support the hypothesis that motion sickness is preceded by instability in the control of seated posture. Application: Potential applications of this research include changes in the design of console video games and recommendations for how such systems should be used.

We investigated whether postural instability can predict motion sickness and studied relations among instability, motion sickness, and vection. Nine men and 4 women (mean age = 19.85 years) were exposed, while standing, to an optical simulation of body sway. Head motion was recorded using a magnetic tracking system. Postural instabilities were observed prior to the onset of motion sickness. Vection was reported by most participants, including all who became ill. A discriminant analysis revealed that parameters of postural motion accurately predicted motion sickness. The results confirm that postural instability precedes motion sickness and suggest that measures of postural motion may serve as reliable predictors of motion sickness. Potential applications of this research include the development of on-line diagnostic tools that will allow for the prevention of motion sickness in operational and training settings.

Abstract

Background
In a secondary analysis of data taken from a publicly available database, we examined cognitive performance, postural sway, and relations between them for 4 groups: younger and older individuals with versus without a recent history of falls. Our objective was to compare linear versus nonlinear measures of postural activity as post hoc predictors of cognitive performance and falling.


Methods
We evaluated standing body sway in 147 participants (18–85-years old) over 60 seconds, separately with eyes-open and with eyes-closed. We evaluated cognitive performance using portions of the Trail Making Test. We evaluated postural activity in terms of standard deviation, velocity, and amplitude of the Center of Pressure (CoP). Separately, we used detrended fluctuation analysis (DFA) to examine the complexity of CoP displacements. Using analysis of variance, we conducted separate analyses of cognitive performance and postural activity comparing Younger and Older Adults and Non-fallers and Fallers, taking into account Vision (eyes-closed vs open) and the direction of postural movements (Anteroposterior vs Mediolateral) while also controlling for participants' characteristics. We used moderation analyses to evaluate whether relationships between Trail Making Test scores and the linear and nonlinear outcomes were moderated by Age group or Fall status.


Results
For postural activity, only DFA differed between Non-fallers and Fallers. Older adults exhibited increased complexity associated with better processing speed function, while fallers show an opposite association, relying on processing speed to increase postural rigidity instead of facilitating adaptive control of balance.


Conclusions
We conclude that DFA can provide information regarding postural activity and cognitive performance that cannot be obtained from more traditional, linear measures of postural activity and that DFA may be a valuable tool for assessing fall risk.

Objective: We tested the hypotheses that (a) participants might develop motion sickness while playing "off-the-shelf" console video games and (b) postural motion would differ between sick and well participants, prior to the onset of motion sickness. Background: There have been many anecdotal reports of motion sickness among people who play console video games (e.g., Xbox, PlayStation). Method: Participants (40 undergraduate students) played a game continuously for up to 50 min while standing or sitting. We varied the distance to the display screen (and, consequently, the visual angle of the display). Results: Across conditions, the incidence of motion sickness ranged from 42% to 56%; incidence did not differ across conditions. During game play, head and torso motion differed between sick and well participants prior to the onset of subjective symptoms of motion sickness. Conclusion: The results indicate that console video games carry a significant risk of motion sickness. Application: Potential applications of this research include changes in the design of console video games and recommendations for how such systems should be used.

Objective: We examined motion sickness in an oscillating virtual environment presented via a video projector system. Background: Visible oscillation of the physical environment is known to induce both postural instability and motion sickness, but it cannot be assumed that the same phenomena will occur in a virtual simulation of such motion. Method: Standing participants (3 men and 9 women, 20—22 years of age) were exposed to oscillation of a virtual room. The stimulus was a computer-generated simulation of a laboratory device that is known to induce postural instability and motion sickness. Participants viewed the simulation for up to 40 min and were instructed to discontinue if they experienced symptoms of motion sickness. Results: Motion sickness incidence (42%) did not differ from that in studies using the corresponding physical moving room. Prior to motion sickness onset, the sick group exhibited changes in movement, relative to the well group, as predicted by the postural instability theory of motion sickness. Differences in movement between the sick and well groups developed over time, in contrast with previous studies using physical moving rooms, in which such movement differences have not evolved. Conclusion: The results indicate that changes in postural activity precede motion sickness that is induced by an oscillating virtual environment, but they also reveal differences in postural responses to virtual and physical motion environments. Application: Potential applications of this research include recommendations for the use of virtual environments as models for perception and action in physical environments.

Adults who are blind stood in a room that could be moved around them. A sound source moved with the room, simulating the acoustic consequences of body sway. Body sway was greater when the room moved than when it was stationary, suggesting that sound may have been used to control stance.

We evaluated the prediction that postural instability would precede the subjective symptoms of motion sickness in a fixed-base flight simulator. Participants sat in a cockpit in a video projection dome and were exposed to optical flow that oscillated in the roll axis with exposure durations typical of flight simulation. The frequencies of oscillation were those that characterize spontaneous postural sway during stance. Head motion was measured prior to and during exposure to imposed optical flow. Of 14 participants, 6 were classified as motion sick, either during or after exposure to the optical oscillation. Prior to the onset of subjective symptoms, head motion among participants who later became sick was significantly greater than among participants who did not become motion sick. We argue that the results support the postural instability theory of motion sickness. Actual or potential applications include the prevention or mitigation of motion sickness in virtual environments.