Features of the Postural Sway Signal as Indicators to Estimate and Predict Visually Induced Motion Sickness in Virtual Reality

Abstract

International audienceNavigation in a 3D immersive virtual environment is known to be prone to visually induced motion sickness (VIMS). Several psychophysiological and behavioral methods have been used to measure the level of sickness of a user, among which is postural instability. This study investigates all the features that can be extracted from the body postural sway: area of the projection of the center of gravity (mainly considered in past studies) and its shape and the frequency components of the signal's spectrum, in order to estimate and predict the occurrence of sickness in a typical virtual reality (VR) application. After modeling and simulation of the body postural sway, an experiment on 17 subjects identified a relation between the level of sickness and the variation both in the time and frequency domains of the body sway signal. The results support and go further into detail of findings of past studies using postural instability as an efficient indicator of sickness, giving insight to better monitor VIMS in a VR application

Estimating the sensorimotor components of cybersickness

“…We found strong evidence supporting the role of vection susceptibility and the role of balance control in CS. The correlation between balance control and ΔCS that we observed was negative, opposite to that which was reported in previous literature (e.g., Chardonnet et al, 2017;Stoffregen & Smart, 1998;Takada et al, 2007), although a negative correlation has also been identified in other recent work (Dennison & D'Zmura, 2017Sadiq et al, 2017). We found no evidence of a link between ΔCS and vestibular thresholds or verbal ratings of vection strength.…”

“…In support of this theory lies evidence that motion sickness produced by simple optic flow stimuli is predicted by the temporal dynamics of postural activity (Palmisano et al, 2018). Others have shown that the area of postural sway tends to increase when participants experience CS (Chardonnet et al, 2017).…”

“…The vestibular sense also plays a crucial role in the maintenance of balance control through detecting fluctuations in the inherently unstable human body (Peterka, 2002). Given the relationship between postural instability and CS proposed by Riccio and Stoffregen (1991) and supported by others (e.g., Chardonnet et al, 2017;Takada et al, 2007), it is clear that vestibular sensitivity to self-motion is likely to modulate CS to some degree. Further support for this point arises from evidence of a strong comorbidity between vestibular migraine and sickness susceptibility (Money & Cheung, 1983).…”

“…As well, visual and vestibular cues that convey information about the state of the headon-body are frequently incongruent in VR, which may pose a challenge for the maintenance of stable postural control. The 'postural instability theory' of sickness was formalised by Riccio and Stoffregen (1991; also see Chardonnet et al, 2017;Stoffregen & Smart, 1998;Takada et al, 2007), who suggested that motion sickness emerges as a consequence of postural instability resulting from unfamiliar environmental conditions. In support of this theory lies evidence that motion sickness produced by simple optic flow stimuli is predicted by the temporal dynamics of postural activity (Palmisano et al, 2018).…”

“…The studies discussed here provide a wealth of evidence about the possible causes of heterogeneity in CS. Principally, these factors include balance control (Chardonnet et al, 2017;Takada et al, 2007), vestibular motion sensitivity (Cheung et al, 1991;Diamond & Markham, 1991;Hoffer et al, 2003), and visual motion/self-motion perception (Allen et al, 2016;Keshavarz et al, 2015). However, no studies have assessed the relative impact of each factor.…”