Elsevier

Displays

Volume 60, December 2019, Pages 18-23
Displays

Effect of virtual reality and whole-body heating on motion sickness severity: A combined and individual stressors approach

https://doi.org/10.1016/j.displa.2019.08.007Get rights and content

Highlights

  • We postulate that heat stress, in addition to a VR stimulus may trigger a heightened nauseogenic response and VIMS.

  • Data does not provide unequivocal evidence of a synergistic interaction between a heat exposure and VR use on VIMS.

  • Despite no statistical synergistic interaction, trends towards synergism were seen in VIMS questionnaire data, vasomotor and sudomotor activity.

  • Considerable individual variation was seen in resistance to motion sickness, limiting the statistical power available for a significant interaction.

  • Vasomotor activity showed conflict between the vasoconstriction induced by VR and vasodilatation induced by heat.

Abstract

Background

Virtual reality (VR) use is limited by the potential side effects of prolonged exposure to vection, leading to motion sickness. Air temperature (Ta) may exacerbate the severity of such side effects through a synergistic interaction. This study assessed the individual and combined impact of a hot Ta and VR on motion sickness severity.

Method

Thirteen healthy volunteers were exposed to a 20 min visual stimulus, across four experimental conditions: N_CS: 22 °C Ta with computer screen; N_VR: 22 °C Ta with VR; H_CS: 35 °C Ta with computer screen; H_VR: 35 °C Ta with VR. Motion sickness was assessed via fast motion sickness scale (FMS) and simulator sickness questionnaire (SSQ). Physiological indices of motion sickness including, sweat rate, rectal temperature, cutaneous vascular conductance (CVC), skin temperature, blood pressure and heart rate were also examined.

Results

FMS and SSQ ratings indicate a significant main effect for VR, increasing sickness severity (p < 0.001). A significant main effect of Ta was observed for SSQ, but not FMS ratings (FMS, p = 0.07; SSQ, p < 0.04). Despite trends towards synergism, no interaction (Ta × VR) was observed for FMS (p = 0.2) or SSQ scores (p = 0.07), indicating an additive response. Synergistic trends were also observed for sweat rate and CVC.

Conclusion

Synergism between VR and heat on motion sickness remains unclear, possibly as a result of considerable inter-individual variation in the reported subjective responses. Understanding of the questions raised by this study inform safe working guidelines for the use of VR in commercial and occupational settings.

Introduction

Advances in Virtual Reality technology (VR) has attracted interest across a range of occupational fields, including medical, military and educational industries. For example, users are now able to artificially experience complex occupational scenarios with reduced risk of injury, damage or cost. Yet, despite the efforts of many manufacturers, there are concerns regarding the associated side effects of prolonged VR use, including malaise, dizziness, headache and eyestrain [1], [2]. In many cases VR use has shown to increase the risk of visually-induced motion sickness (VIMS), also known as cybersickness, with ongoing debate concerning to the direct influence of perceived self-motion (vection) [3], [4], [5], [6], [7], [8], [9]. For example, an observational study comparing ratings of VIMS in 497 healthy adults, reported a 55% vs. 14% prevalence of sickness, having viewed a 3D and 2D movie respectively [10]. Symptom intensity was also observed to be significantly higher following 3D compared to 2D viewing. Comparable to ‘classical’ motion sickness, common symptoms of VIMS may present as dizziness, vertigo, sweating, stomach awareness and nausea, which may further progress to vomiting with sufficient stimulus duration or intensity [11], [12], [13]. Given the scope and utility of VR technology, it is important to better understand the underlying mechanisms, mediating factors and interactions which may link VR with VIMS, thus maximising its future potential.

Due to the complex nature of motion sickness there is limited agreement on a holistic and theoretical understanding of the mechanisms that cause the syndrome [14]. Indeed, it has even been reported that motion sickness can develop prior to exposure to a provocative stimulus, perhaps due to expectancy or anxiety effects [14]. At present, several hypotheses exist to explain the cause of motion sickness; (i) Sensory Conflict and Rearrangement Theory [15], in which sensory information from visual, vestibular and somatosensory systems, either become mismatched, or if these senses fail to match those stored in the central nervous system from past experiences; (ii) Postural Instability Theory [16], in which an organism attempts to maintain postural stability in relation to its environment throughout daily activities, with sickness occurring when a stable state can no longer be obtained, along with a perceived lack of control; (iii) Poison Theory or the Toxic Hypothesis [17], an evolutionary response in which emesis acts as a defence mechanism to intoxication of the body due to toxin induced stimulation of the vestibular senses. The net result of the latter is a mismatch between perceived moving vestibular and static visual signals, consequently leading to emesis, vertigo, dizziness and postural instability.

There is also limited research on the secondary and mediating factors that subsequently impact upon VIMS susceptibility during VR use. One such factor is air temperature (Ta), including both hot and cold stimuli. Interestingly, previous studies have highlighted interactions between motion sickness and thermoregulation, showing an increased risk of deep-body cooling in motion sick individuals, when exposed to cold environments [18], [19]. In view of the toxic hypothesis, its appears conceivable that this reduction in deep-body temperature may act in conjunction with motion sickness, to further protect the body against perceived intoxication via a slowing of metabolic rate [20]. We further postulate that an added thermoregulatory load induced via heat stress, in addition to a provocative VR stimulus, may artificially strengthen the body’s belief that it is under threat from intoxication, subsequently triggering a heightened nauseogenic response [20]. As such, it is possible that a mechanistic interaction of a synergistic nature may exist between heat exposure (i.e. prolonged exposures to Ta > 30 °C) and VR use, on VIMS susceptibility [21]. While the toxic hypothesis provides a potential explanation for a synergistic interaction between heat and VR, if an interaction is not observed (i.e. additive effects), this may better support the role of other theories such as sensory conflict, in the aetiology of motion sickness.

To understand the role of a hot air temperature in modulating nausea in virtual reality, this investigation examined the combined and differential impacts of heat and VR on motion sickness severity. Three hypotheses were constructed; 1. individuals would report significantly greater perceptions of VIMS whilst viewing VR, when compared to a computer screen control, 2. individuals would not report any difference in VIMS under hot conditions, compared to a thermoneutral control, 3. combined VR and hot conditions would synergistically interact to significantly increase VIMS ratings when compared to either factor independently. An understanding of such main effects and potential interactions is likely to better inform safe working guidelines for the use of VR in commercial and occupational settings, as well as elucidating some of the underlying mechanisms impacting VIMS.

Section snippets

Participants

Thirteen healthy volunteers, five male and eight females (age, 25 ± 3 yrs), were recruited from the Loughborough, UK between June and November 2017. Inclusion criteria detailed: non-smoking, otherwise healthy individuals, reporting no significant (>6 hrs per week) gaming or VR experience. All participants provided written informed consent. Ethical approval was granted by the Loughborough University Ethics Committee and the research was conducted in accordance with the Declaration of Helsinki,

Results

All participants successfully completed the experiment, undertaking all trials, despite varying reports of motion sickness.

Discussion

This study aimed to assess the combined and differential impact of a hot air temperature and virtual reality on motion sickness severity and the associated thermoeffectors (sweating, vasomotor activity). In accordance with the aim, three hypotheses are discussed:

Acknowledgements

G.A Raccuglia is acknowledged for his help and support during data collection.

Declaration of Competing Interest and sources of funding

The authors declare they have no conflict of interest and the study did not receive funding from external sources to Loughborough University.

Josh T. Arnold (MRes) is a PhD researcher in the Environmental Ergonomics Research Centre at Loughborough University. His research seeks to investigate the individual and combined impact of multifactorial extreme environments on human function and capacity. Prior to this, Josh held a research position at Southampton Solent University, publishing across numerous topics including translational physiology and public health. In 2012 Josh studied for a masters by research degree at Bangor University

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  • Cited by (4)

    Josh T. Arnold (MRes) is a PhD researcher in the Environmental Ergonomics Research Centre at Loughborough University. His research seeks to investigate the individual and combined impact of multifactorial extreme environments on human function and capacity. Prior to this, Josh held a research position at Southampton Solent University, publishing across numerous topics including translational physiology and public health. In 2012 Josh studied for a masters by research degree at Bangor University focusing on the physiology of sport and exercise.

    Kate O’Keeffe (MSc) is a current PhD researcher at the Environmental Ergonomics Research Centre, Loughborough University, UK. Her research surrounds cognitive and physical performance in extreme environments. She completed a double master's degree in sports and exercise psychology and diagnostics and intervention studies from the University of Jyväskylä, Finland and Leipzig University, Germany respectively in 2016. She is also a qualified and experienced physical education and mathematics teacher.

    Chloe McDaniel (MSc) is an ergonomist working as an occupational health and safety consultant for Human Applications based in Loughborough, England. Prior to working in health and safety, Chloe received her MSc in Ergonomics and Human Factors (2017) from Loughborough University. She completed her master’s thesis in the Environmental Ergonomics Research Centre, exploring the effects of environmental temperatures on motion sickness when using virtual reality.

    Dr Simon Hodder (PhD) is a Senior Lecturer in the Environmental Ergonomics Research Centre in the Loughborough Design School. He has over 20 years’ experience working in the field of environmental ergonomics: thermal, vision and virtual reality. He is a scientific editor for Applied Ergonomics and is Chairman of ISO/TC159/Scientific Committee 5 (Ergonomics of the Physical Environment).

    Dr Alex Lloyd (PhD) is a researcher and full time academic in Environmental Ergonomics and Human Physiology at Loughborough University. After working for the Royal Air Force Centre of Aviation Medicine, Dr Lloyd attained his PhD in Neuromuscular Physiology from Loughborough University. Dr Lloyd has since published widely across the fields of Integrative Physiology, Temperature Regulation and Environmental Ergonomics. His current research is centred on the impact of multiple environmental stressors on human physical and cognitive performance. Dr Lloyd is an Associate Editor at the journal Ergonomics.

    This paper was recommended for publication by Richard H.Y. So.

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