Rest intervals during virtual reality gaming augments standing postural sway disturbance

Immersive virtual reality (VR) can cause acute sickness, visual disturbance, and balance impairment. Some manufacturers recommend intermittent breaks to overcome these issues; however, limited evidence examining whether this is beneficial exists. The aim of this study was to examine whether taking breaks during VR gaming reduced its effect on postural sway during standing balance assessments. Twenty-five people participated in this crossover design study, performing 50 min of VR gaming either continuously or with intermittent 10 min exposure/rest intervals. Standing eyes open, two-legged balance assessments were performed immediately pre-, immediately post- and 40 min post-exposure. The primary outcome measure was total path length; secondary measures included independent axis path velocity, amplitude, standard deviation, discrete and continuous wavelet transform-derived variables, and detrended fluctuation analysis. Total path length was significantly (p < 0.05) reduced immediately post-VR gaming exposure in the intermittent rest break group both in comparison to within-condition baseline values and between-condition timepoint results. Conversely, it remained consistent across timepoints in the continuous exposure group. These changes consisted of a more clustered movement speed pattern about a lower central frequency, evidenced by signal frequency content. These findings indicate that caution is required before recommending rest breaks during VR exposure until we know more about how balance and falls risk are affected.Ross Allan Clark, Ancret Szpak, Stefan Carlo Michalski, and Tobias Loetsche

THE EFFECT OF 0.2 HZ AND 1.0 HZ FREQUENCY AND 100 MS AND 20 - 100 MS AMPLITUDE OF LATENCY ON SIMULATORY SICKNESS IN A HEAD MOUNTED DISPLAY

The purpose of the current experiment was to contribute to the existing literature on the relationship between frequency of latency and amplitude of latency and simulator sickness experienced in a head mounted display (HMD). Motion sickness has been studied for decades in a variety of vehicles including ships, planes, trains and automobiles. More recently virtual environments, including those utilizing an HMD have been shown to generate significant sickness, often termed simulator sickness. Many studies have linked system latency to simulator sickness and recent research has found that with current technology latency is not a constant; but rather it varies systematically over time due to sensor errors and clock asynchronization. One hundred twenty participants were recruited and randomly assigned to one of four conditions (0.2 Hz frequency of latency with 100 ms fixed amplitude of sinusoidal latency; 0.2 Hz frequency of latency with 20 - 100 ms varying amplitude of sinusoidal latency; 1.0 Hz frequency of latency with 100 ms fixed amplitude of sinusoidal latency; 1.0 Hz frequency of latency with 20 - 100 ms varying amplitude of sinusoidal latency). Collected data were analyzed using analysis of variance. A main effect of frequency of latency was found, and data trended toward a main effect of amplitude of latency. Participants reported greater sickness in 0.2 Hz frequency conditions and in the 1 Hz varying amplitude condition, indicating both frequency and amplitude of latency contribute to simulator sickness and are important factors to consider in regard to system latency. In conclusion, both frequency and amplitude of latency play an important role in simulator sickness

Методи пом'якшення

The section describes mitigation methods.У розділі описано методи помякшення

Can Simulator Sickness Be Avoided? A Review on Temporal Aspects of Simulator Sickness

Simulator sickness is a syndrome similar to motion sickness, often experienced during simulator or another virtual reality (VR) exposure. Many theories have been developed or adapted from the motion sickness studies, in order to explain the existence of the syndrome. The simulator sickness can be measured using both subjective and objective methods. The most popular self-report method is the Simulator Sickness Questionnaire. Attempts have also been made to discover a physiological indicator of the described syndrome, but no definite conclusion has been reached on this issue. In the present paper, three temporal aspects of the simulator sickness are discussed: the temporal trajectory of the progression of simulator sickness, possibility of adapting VR users in advance and persistence of the symptoms after VR exposure. Evidence found in 39 articles is widely described. As for the first aspect, it is clear that in most cases severity of the simulator sickness symptoms increases with time of exposure, although it is impossible to develop a single, universal pattern for this effect. It has also been proved, that in some cases a threshold level or time point exists, after which the symptoms stop increasing or begin to decrease. The adaptation effect was proved in most of the reviewed studies and observed in different study designs – e.g., with a couple of VR exposures on separate days or on 1 day and with a single, prolonged VR exposure. As for the persistence of the simulator sickness symptoms after leaving the VR, on the whole the study results suggest that such an effect exists, but it varies strongly between individual studies – the symptoms may persist for a short period of time (10 min) or a relatively long one (even 4 h). Considering the conclusions reached in the paper, it is important to bear in mind that the virtual reality technology still evokes unpleasant sensations in its users and that these sensations should be cautiously controlled while developing new VR tools. Certainly, more research on this topic is necessary

Cybersickness: a multisensory integration perspective

In the past decade, there has been a rapid advance in Virtual Reality (VR) technology. Key to the user’s VR experience are multimodal interactions involving all senses. The human brain must integrate real-time vision, hearing, vestibular and proprioceptive inputs to produce the compelling and captivating feeling of immersion in a VR environment. A serious problem with VR is that users may develop symptoms similar to motion sickness, a malady called cybersickness. At present the underlying cause of cybersickness is not yet fully understood. Cybersickness may be due to a discrepancy between the sensory signals which provide information about the body’s orientation and motion: in many VR applications, optic flow elicits an illusory sensation of motion which tells users that they are moving in a certain direction with certain acceleration. However, since users are not actually moving, their proprioceptive and vestibular organs provide no cues of self-motion. These conflicting signals may lead to sensory discrepancies and eventually cybersickness. Here we review the current literature to develop a conceptual scheme for understanding the neural mechanisms of cybersickness. We discuss an approach to cybersickness based on sensory cue integration, focusing on the dynamic re-weighting of visual and vestibular signals for self-motion

Psychometric correlates of multisensory integration as potential predictors of cybersickness in virtual reality

Humans are constantly presented with rich sensory information through the environment that the central nervous system (CNS) must process to form a coherent perception of the world. While the CNS may be efficient in doing so in natural environments, human-made environments such as virtual reality (VR) pose challenges for the CNS to integrate multisensory information. While VR systems are becoming widely used in various fields, it often causes cybersickness in users. Cybersickness may be due to temporal discrepancies in visually updating the environment after a movement. We sought to assess whether individual differences in the parameters of temporal order judgement of multisensory cues are related to cybersickness. We tested 50 participants in two different tasks. The first task involved two temporal order judgements, 1) an audio-visual (AV) and 2) an audio-active head movement (AAHM) task where participants were presented with a sound paired with a visual or head movement stimulus at different stimulus onset asynchronies. The second task involved exploration of two VR experiences for 30 minutes each where participants’ cybersickness was quantified every 2 minutes on the fast motion sickness scale and also at the end of the 30-minute period using the simulator sickness questionnaire (SSQ). Participants’ visual acuity was also assessed. Results demonstrate that there is a positive correlation between total SSQ scores and the temporal binding window (TBW) and point of subjective simultaneity (PSS) measures. These indicate that individuals with wider AV TBWs or larger PSS measures may be more susceptible to cybersickness. We also find that individuals with higher visual acuity report lower sickness symptoms which is contrary to previous studies. Results from such findings will generate a better understanding of cybersickness in VR which in turn can be used for future development of virtual environments so as to be able to minimize discomfort

Чинники, що спричиняють кіберхвороби

The section discusses factors impacting cybersickness.У розділі розглянуто чинники, що спричиняють кіберхвороби