Virtual reality sickness

Virtual reality sickness may have undesirable consequences beyond the sickness itself. For example, Crowley (1987) argued that flight simulator sickness could discourage pilots from using flight simulators, reduce the efficiency of training through distraction and the encouragement of adaptive behaviors that are unfavorable for performance, compromise ground safety or flight safety when sick and disoriented pilots leave the simulator.{{cite journal|last1=Crowley|first1=J. S.|title=Simulator sickness: A problem for Army Aviation|journal=Aviation, Space, and Environmental Medicine|date=1987|volume=58|issue=4|pages=355–357|pmid=3579825}} Similar consequences could be expected for virtual reality systems. Although the evidence for performance decrements due to virtual reality sickness is limited,{{cite journal|last1=Barrett|first1=J.|title=Side effects of virtual environments: A review of the literature (DSTO-TR-1419)|date=2004|url=http://dspace.dsto.defence.gov.au/dspace/bitstream/1947/4079/1/DSTO-TR-1419%20PR.pdf|publisher=Defense Sciences and Technology Organisation Information Sciences Laboratory|location=Edinburgh, Australia|access-date=2016-01-16|archive-date=2016-10-09|archive-url=https://web.archive.org/web/20161009115824/http://dspace.dsto.defence.gov.au/dspace/bitstream/1947/4079/1/DSTO-TR-1419%20PR.pdf|url-status=dead}} research does suggest that virtual reality sickness is a major barrier to using virtual reality,{{cite journal|last1=Brooks|first1=J. O.|last2=Goodenough|first2=R. R.|last3=Crisler|first3=M. C.|last4=Klein|first4=N. D.|last5=Alley|first5=R. L.|last6=Koon|first6=B. L.|last7=Logan Jr. |first7=W.C. |last8=Ogle |first8=J.H. |last9=Tyrrell |first9=R.A. |last10=Wills |first10=R.F. |title=Simulator sickness during driving simulation studies|journal=Accident Analysis & Prevention|date=2010|volume=42|issue=3|pages=788–796|doi=10.1016/j.aap.2009.04.013|pmid=20380904}} indicating that virtual reality sickness may be a barrier to the effective use of training tools and rehabilitation tools in virtual reality. Estimates of the multi-study incidence and main symptoms of virtual reality sickness (also called cybersickness) have been made.{{cite book|author=Lawson, B. D. |year=2014|chapter=Motion sickness symptomatology and origins|title=Handbook of Virtual Environments: Design, Implementation, and Applications|pages=531–599}}

Virtual reality sickness is closely related to simulator and motion sickness. Sensory conflict theory provides a framework for understanding motion sickness; however, it can be applied to virtual reality sickness to better understand how it can occur,{{cite journal|last1=Johnson|first1=D.|title=Introduction to and Review of Simulator Sickness Research (Research Report 1832)|date=April 2005|publisher=U.S. Army Research Institute for the Behavioral and Social Sciences}} and is commonly used for that purpose. Sensory conflict theory posits that sickness will occur when a user's perception of self-motion is based on incongruent sensory inputs from the visual system, vestibular system, and non-vestibular proprioceptors, and particularly so when these inputs are at odds with the user's expectation based on prior experience.{{cite book|last1=Reason|first1=J. T.|last2=Brand|first2=J. J.|title=Motion sickness|date=1975|publisher=Academic Press|location=London}} Applying this theory to virtual reality, sickness can be minimized when the sensory inputs inducing self-motion are in agreement with one another.{{citation needed|date=July 2021}}

A major trigger of virtual reality sickness is when there is disparity in apparent motion between the visual and vestibular stimuli. This disparity occurs if there is a disagreement between what the stimuli from the eyes and inner ear are sending to the brain. This is a fundamental cause of both simulator and motion sickness as well. In virtual reality, the eyes transmit that the person is running and jumping through a dimension, however, the ears transmit that no movement is occurring and that the body is sitting still. Since there is this discord between the eyes and the ears, a form of motion sickness can occur.

The images projected from typical virtual reality headsets have a major impact on sickness. The refresh rate of on-screen images is often not high enough when VR sickness occurs.{{Cite journal |last1=Kourtesis |first1=Panagiotis |last2=Collina |first2=Simona |last3=Doumas |first3=Leonidas A. A. |last4=MacPherson |first4=Sarah E. |date=2019 |title=Technological Competence Is a Pre-condition for Effective Implementation of Virtual Reality Head Mounted Displays in Human Neuroscience: A Technological Review and Meta-Analysis |journal=Frontiers in Human Neuroscience |volume=13 |page=342 |doi=10.3389/fnhum.2019.00342 |issn=1662-5161 |pmc=6783565 |pmid=31632256 |doi-access=free }} Because the refresh rate is slower than what the brain processes, it causes a disconnect between the processing rate and the refresh rate, which causes the user to perceive glitches on the screen. When these two components do not match up, it can cause the user to experience the same feelings as simulator and motion sickness which is mentioned below.

The resolution on animation can also cause users to experience this phenomenon. When animations are poor, it causes another type of discord between what is expected and what is actually happening on the screen. When onscreen graphics do not keep the pace with the users' head movements, it can trigger a form of motion sickness.

Not all scientists agree with sensory conflict theory. A second theory of motion sickness, which has also been used to explain virtual reality sickness, is the theory of postural instability.{{cite journal|last1=Stoffregen|first1=T. A.|last2=Riccio|first2=G. E.|title=An ecological theory of orientation and the vestibular system|journal=Psychological Review|date=1988|volume=95|issue=1|pages=3–14|doi=10.1037/0033-295x.95.1.3|pmid=3281178}} This theory holds that motion sickness and related sicknesses occur because of poor postural adaptations in response to unusual coupling between visual stimuli and motor coordination. Characteristic markers of postural instability occur prior to appearance of symptoms and predict the later development of symptoms.{{cite journal|author1=Smart, L. J.|author2=Stoffregen, T. A.|author3=Bardy, B. G.|year=2002|name-list-style=amp|title=Visually induced motion sickness predicted by postural instability|journal=Human Factors|volume=44|issue=3|pages=451–465|doi=10.1518/0018720024497745|pmid=12502162|s2cid=7885908}} This theory can explain some otherwise surprising situations in which motion sickness did not occur in the presence of sensory conflict.{{cite journal|last1=Riccio|first1=G. E.|last2=Martin|first2=E. J.|last3=Stoffregen|first3=T. A.|title=The role of balance dynamics in the active perception of orientation|journal=Journal of Experimental Psychology: Human Perception and Performance|date=1992|volume=18|issue=3|pages=624–644|doi=10.1037/0096-1523.18.3.624|pmid=1500866}}

There are various technical aspects of virtual reality that can induce sickness, such as mismatched motion,{{cite journal|last1=Groen|first1=E.|last2=Bos|first2=J.|title=Simulator sickness depends on frequency of the simulator motion mismatch: An observation|journal=Presence|date=2008|volume=17|issue=6|pages=584–593|doi=10.1162/pres.17.6.584|s2cid=43585717}} field of view,{{cite book|last1=Lin|first1=J. J.|title=Proceedings IEEE Virtual Reality 2002|last2=Duh|first2=H. B. L.|last3=Parker|first3=D. E.|last4=Abi-Rached|first4=H.|last5=Furness|first5=T. A. |date=2002|volume=9|pages=164–171|doi=10.1109/VR.2002.996519|isbn=978-0-7695-1492-5|chapter=Effects of field of view on presence, enjoyment, memory, and simulator sickness in a virtual environment|s2cid=34936854}} motion parallax,{{cite journal|last1=Jinjakam|first1=C.|last2=Kazuhiko|first2=H.|title=Study on parallax affect on simulator sickness in one-screen and three-screen immersive virtual environment|journal=東海大学紀要情報通信学部|date=2011|volume=4|issue=1|pages=34–39}} and viewing angle.{{cite book|last1=Ruddle|first1=R. A. |title=IEEE Virtual Reality 2004 |date=2004|volume=11|pages=141–148|doi=10.1109/VR.2004.1310067|isbn=978-0-7803-8415-6|citeseerx=10.1.1.294.5953|chapter=The effect of environment characteristics and user interaction on levels of virtual environment sickness }} Additionally, the amount of time spent in virtual reality can increase the presence of symptoms.{{Cite journal |last1=Kourtesis |first1=Panagiotis |last2=Collina |first2=Simona |last3=Doumas |first3=Leonidas A. A. |last4=MacPherson |first4=Sarah E. |date=2019 |title=Validation of the Virtual Reality Neuroscience Questionnaire: Maximum Duration of Immersive Virtual Reality Sessions Without the Presence of Pertinent Adverse Symptomatology |journal=Frontiers in Human Neuroscience |volume=13 |page=417 |doi=10.3389/fnhum.2019.00417 |issn=1662-5161 |pmc=6901952 |pmid=31849627 |doi-access=free }}

Mismatched motion can be defined as a discrepancy between the motion of the simulation and the motion that the user expects. It is possible to induce motion sickness in virtual reality when the frequencies of mismatched motion are similar to those for motion sickness in reality, such as seasickness. These frequencies can be experimentally manipulated, but also have the propensity to arise from system errors.

Generally, increasing the field of view increases incidence of simulator sickness symptoms. This relationship has been shown to be curvilinear, with symptoms approaching an asymptote for fields of view above 140°.

Altering motion parallax distances to those less than the distance between the human eyes in large multiple-screen simulation setups can induce oculomotor distress, such as headaches, eyestrain, and blurred vision. There are fewer reports of oculomotor distress on smaller screens; however, most simulation setups with motion parallax effects can still induce eyestrain, fatigue, and general discomfort over time.{{citation needed|date=September 2019}}

Viewing angle has been shown to increase a user's sickness symptoms, especially at extreme angles. One example of such an extreme angle would be when a user must look downwards a short distance in front of their virtual feet. As opposed to a forward viewing angle, an extreme downward angle such as this has been shown to markedly increase sickness in virtual environments.

Time spent immersed in a virtual environment contributes to sickness symptom presence due to the increasing effects of fatigue on the user. Oculomotor symptoms are the most common to occur due to immersion time, but the nature of the user's movements (e.g., whole-body vs. head-only) is suggested to be the primary cause of nausea or physical sickness.

According to several studies, introducing a static frame of reference (independent visual background) may reduce simulation sickness.{{Cite journal|last1=Lin|first1=James Jeng-Weei|last2=Abi-Rached|first2=Habib|last3=Kim|first3=Do-Hoe|last4=Parker|first4=Donald E.|last5=Furness|first5=Thomas A.|date=2002-09-01|title=A "Natural" Independent Visual Background Reduced Simulator Sickness|journal=Proceedings of the Human Factors and Ergonomics Society Annual Meeting|language=en|volume=46|issue=26|pages=2124–2128|doi=10.1177/154193120204602605|issn=1541-9312|citeseerx=10.1.1.897.4716|s2cid=145258344}}{{Cite journal|last1=Prothero|first1=J. D.|last2=Draper|first2=M. H.|last3=Furness|first3=T. A.|last4=Parker|first4=D. E.|last5=Wells|first5=M. J.|date=March 1999|title=The use of an independent visual background to reduce simulator side-effects|journal=Aviation, Space, and Environmental Medicine|volume=70|issue=3 Pt 1|pages=277–283|issn=0095-6562|pmid=10102741}}{{Cite book|title=Does a Peripheral Independent Visual Background Reduce Scene-Motion-Induced Balance Disturbance in an Immersive Environment?|last1=Duh|first1=Henry Been-Lirn|last2=Parker|first2=Donald E.|last3=Furness|first3=Thomas A.|date=2001|citeseerx = 10.1.1.29.3699}} A technique called Nasum Virtualis shows a virtual nose as a fixed frame of reference for VR headsets.Whittinghill, D. M., Ziegler, B., Moore, J., & Case, T. (2015). Nasum Virtualis: A Simple Technique for Reducing Simulator Sickness in Head Mounted VR. In Game Developers Conference. San Francisco. [https://www.gdcvault.com/play/1022287/Technical-Artist-Bootcamp-Nasum-Virtualis]{{Cite magazine|url=https://www.wired.com/2015/04/reduce-vr-sickness-just-add-virtual-nose/|title=How to Reduce VR Sickness? Just Add a Virtual Nose|magazine=WIRED|access-date=2017-10-11|language=en-US}}

Other techniques for reducing nausea involve simulating ways of displacement that don't create or reduce discrepancies between the visual aspects and body movement, such as room-scale VR, reducing rotational motions during navigation,{{Cite journal|last1=Kemeny|first1=Andras|last2=George|first2=Paul|last3=Mérienne|first3=Frédéric|last4=Colombet|first4=Florent|date=2017-01-29|title=New VR Navigation Techniques to Reduce Cybersickness|journal=Electronic Imaging|volume=2017|issue=3|pages=48–53|doi=10.2352/ISSN.2470-1173.2017.3.ERVR-097|url=http://cdm21054.contentdm.oclc.org/cdm/ref/collection/IR/id/3374|hdl=10985/13057|hdl-access=free}} dynamically reducing the field of view,{{Cite book|last1=Fernandes|first1=A. S.|last2=Feiner|first2=S. K.|date=March 2016 |pages=201–210|doi=10.1109/3DUI.2016.7460053|isbn=978-1-5090-0842-1|chapter=Combating VR sickness through subtle dynamic field-of-view modification|title=2016 IEEE Symposium on 3D User Interfaces (3DUI)|s2cid=14964767}} teleportation,{{Cite news|url=https://vr.arvilab.com/blog/combating-vr-sickness-debunking-myths-and-learning-what-really-works|title=Combating VR Sickness: Debunking Myths And Learning What Really Works|work=ARVI Games|archive-url=https://web.archive.org/web/20190328213733/https://vr.arvilab.com/blog/combating-vr-sickness-debunking-myths-and-learning-what-really-works|archive-date=2019-03-28}} and movement in zero gravity.{{Cite news|url=https://www.theverge.com/2016/10/13/13261342/virtual-reality-oculus-rift-touch-lone-echo-robo-recall|title=How game designers find ways around VR motion sickness|work=The Verge|access-date=2017-10-11}}

In January 2020, the French start-up Boarding Ring, known for their glasses against motion sickness,{{cite web|title=Could These Glasses Cure Your Motion Sickness? - smithsonianmag.com|url=https://www.smithsonianmag.com/innovation/could-these-glasses-cure-your-motion-sickness-180969722/|website=smithsonianmag.com}} released an add-on device against virtual reality sickness.{{cite web|title=The Seenetic VR Sickness Solution - intotomorrow.com|date=24 January 2020 |url=https://intotomorrow.com/the-seenetic-vr-sickness-solution/}} Using two small screens in the user's peripheral field of view, the device displays visual information consistent with vestibular inputs, avoiding the sensory conflict.

Galvanic vestibular stimulation, which creates the illusion of motion by electric stimulation of the vestibular system, is another technique being explored for its potential to mitigate or eliminate the visual-vestibular mismatch.{{Cite news|url=https://www.forbes.com/sites/jasonevangelho/2016/03/30/mayo-clinic-may-have-just-solved-one-of-virtual-realitys-biggest-problems|title=Mayo Clinic May Have Just Solved One Of Virtual Reality's Biggest Problems|work=Forbes|access-date=2019-03-08|language=en-US}}

To alleviate these symptoms, methods such as gradual adaptation to VR, the use of natural remedies like ginger, and wearing acupressure bracelets are effective. Choosing VR games designed to minimize motion sickness can also reduce nausea and improve the user experience.{{cite web | url=https://ovrdoz.com/en/how-to-treat-motion-sickness-in-vr/ | title=Motion Sickness in VR: Causes, Symptoms, and Tips | date=30 May 2024 }}

With the integration of virtual reality into the more commercial mainstream, issues have begun to arise in relation to VR sickness in head-mounted gaming devices.{{cite journal|last1=Lang|first1=B.|title=First impressions of Valve's VR head mounted display prototype|journal=Road to Virtual Reality|date=January 16, 2014|url=http://www.roadtovr.com/valve-head-mounted-display-virtual-reality-headset-steam-dev-days/|access-date=14 July 2014}} While research on head-mounted VR for gaming dates back to the early 1990s,{{cite journal|last1=Merhi|first1=O.|last2=Faugloire|first2=E.|last3=Flanagan|first3=M.|last4=Stoffregen|first4=T. A.|title=Motion sickness, video games, and head-mounted displays|journal=Human Factors|date=2007|volume=49|issue=5|pages=920–934|doi=10.1518/001872007x230262|pmid=17915607|s2cid=35259840}} the potential for mass usability has only become recently realized. Contemporary VR headsets appear to induce minimal to none VR sickness.

While certain features are known to moderate VR sickness in head-mounted displays, such as playing from a seated position rather than standing, it has also been found that this merely puts off the onset of sickness, rather than completely preventing it. This inherently presents an issue, in that this type of interactive VR often involves standing or walking for a fully immersive experience. Gaming VR specialists argue that this unique brand of VR sickness is only a minor issue, claiming that it disappears with time spent (multiple days) using the head-mounted displays, relating it to "getting your sea legs".{{cite web|title=The Promise and Challenges of Head-Mounted Virtual Reality Displays - Tested.com|url=http://www.tested.com/tech/gaming/454559-valves-michael-abrash-promise-and-challenges-vr/|website=Tested.com|access-date=14 July 2014}} However, getting users interested in sickness for multiple days with the promise of "probably getting over it" is a struggle for developers of head-mounted gaming tech. Surveys have shown that a large percentage of people won't develop their "VR legs," in particular women.{{cite web|title=VR Motion Sickness Statistics - Age, Gender, Experience and More. VRHeaven.io|url=https://vrheaven.io/vr-motion-sickness-statistics/|website=VRHeaven.io|date=4 July 2020 |access-date=17 July 2020}} These same developers also argue that it has more to do with the individual game being played, and that certain gaming aspects are more likely to create issues, such as change in speed, walking up stairs, and jumping, which are all, unfortunately, fairly normal game functions in predominant genres.

Individuals vary widely in their susceptibility to simulator and virtual reality sickness. Some of the factors in virtual reality sickness are listed below:

• Age: Susceptibility to motion sickness is highest between the ages of 2 and 12. It then decreases rapidly until about age 21, and continues to decrease more slowly after that. It has been suggested that virtual reality sickness might follow a similar pattern, but more recent research has suggested that adults over the age of 50 are more susceptible than younger adults to virtual reality sickness.
• Postural stability: Postural instability has been found to increase susceptibility to visually-induced motion sickness.{{cite journal|last1=Smart|first1=L. J. Jr.|last2=Stoffregen|first2=T. A.|last3=Bardy|first3=B. G.|title=Visually induced motion sickness predicted by postural instability|journal=Human Factors|date=2002|volume=44|issue=3|pages=451–465|doi=10.1518/0018720024497745|pmid=12502162|s2cid=7885908}} It is also associated with increased susceptibility to nausea and disorientation symptoms of virtual reality sickness.{{cite journal|last1=Kolasinski|first1=E. M.|last2=Jones|first2=S. A.|last3=Kennedy|first3=R. S.|last4=Gilson|first4=R. D.|title=Postural stability and its relation to simulator sickness|journal=Poster Presented at the 38th Annual Meeting of the Human Factors and Ergonomics Society|volume=38|issue=15|page=980|date=January 1994|doi=10.1177/154193129403801571|s2cid=58710956}}
• Flicker fusion frequency threshold: Because flicker in the display has been associated with increased risk of virtual reality sickness, people with a low threshold for detecting flicker may be more susceptible to virtual reality sickness.
• Ethnicity: Asian people may be more susceptible to virtual reality sickness. Chinese women appear to be more susceptible to virtual reality sickness than European-American and African-American women; research suggests that they are more susceptible to vision-based motion sickness.{{cite journal|last1=Stern|first1=R. M.|last2=Hu|first2=S.|last3=LeBlanc|first3=R.|last4=Koch|first4=K. L.|title=Chinese hyper-susceptibility to vection-induced motion sickness|journal=Aviation, Space, and Environmental Medicine|date=1993|volume=64|issue=9 Pt 1|pages=827–830|pmid=8216144}} Tibetans and Northeast Indians also appear to be more susceptible to motion sickness than Caucasian people,{{cite journal|last1=Sharma|first1=K|last2=Aparna|title=Prevalence and correlates of susceptibility to motion sickness|journal=Acta Geneticae Medicae et Gemellologiae|date=1997|volume=46|issue=2|pages=105–121|pmid=9492893|doi=10.1017/S0001566000000660|doi-access=free}} suggesting that they would also be more susceptible to virtual reality sickness, since susceptibility to motion sickness predicts susceptibility to a wide range of motion-sickness related disturbances.
• Experience with the system: Users seem to become less likely to develop virtual reality sickness as they develop familiarity with a virtual reality system. Adaptation may occur as quickly as the second exposure to the virtual reality system.{{cite journal|last1=Uliano|first1=K. C.|last2=Lambert|first2=E. Y.|last3=Kennedy|first3=R. S.|last4=Sheppard|first4=D. J.|title=The effects of asynchronous visual delays on simulator flight performance and the development of simulator sickness symptomatology (NAVTRASYSCEN 85-D-0026-1)|publisher=Naval Training Systems Center|location=Orlando, FL}}
• Gender: Women are more susceptible than men to virtual reality sickness.{{cite journal|last1=Kennedy|first1=R. S.|last2=Frank|first2=L. H.|title=A review of motion sickness with special reference to simulator sickness|journal=Paper Presented at the National Academy of Sciences/National Research Council Committee on Human Factors|date=September 1983|location=Monterey, CA}}{{cite journal|last1=Park|first1=G. D.|last2=Allen|first2=R. W.|last3=Fiorentino|first3=D.|last4=Rosenthal|first4=T. J.|last5=Cook|first5=M. L.|title=Simulator sickness scores according to symptom susceptibility, age, and gender for an older driver assessment study|journal=Proceedings of the Human Factors and Ergonomics Society Annual Meeting|date=2006|volume=50|issue=26|pages=2702–2706|doi=10.1177/154193120605002607|s2cid=111310621|doi-access=free}}{{cite journal|last1=Kennedy|first1=R. S.|last2=Lilienthal|first2=M. G.|last3=Berbaum|first3=K. S.|last4=Baltzley|first4=D. R.|last5=McCauley|first5=M. E.|title=Simulator sickness in U.S. Navy flight simulators|journal=Aviation, Space, and Environmental Medicine|date=1989|volume=60|issue=1|pages=10–16|pmid=2923588}}{{cite thesis | last=Boyd | first=Danah | title=Depth Cues in Virtual Reality and the Real World: Understanding Differences in Depth Perception by Studying Shape-from-shading and Motion Parallax. |date=2001 |type=Undergraduate honors thesis | publisher=Brown University | url=http://www.danah.org/papers/sexvision.pdf |access-date = 8 January 2016}} This may be due to hormonal differences, it may be because women have a wider field of view than men, {{Failed verification|date=October 2022}} or gender differences in depth cue recognition. Women are most susceptible to virtual reality sickness during ovulation{{cite journal|last1=Clemes|first1=S. A.|last2=Howarth|first2=P. A.|title=The menstrual cycle and susceptibility to virtual simulator sickness|journal=Journal of Biological Rhythms|date=2005|volume=20|issue=1|pages=71–82|doi=10.1177/0748730404272567|pmid=15654072|s2cid=30696145|doi-access=free}} and a wider field of view is also associated with an increase in virtual reality sickness.{{cite journal|last1=Kennedy|first1=R. S.|last2=Berbaum|first2=K. S.|last3=Lilienthal|first3=M. G.|last4=Dunlap|first4=W. P.|last5=Mulligan|first5=B. F.|last6=Funaro|first6=J. F.|title=Guidelines for alleviation of simulator sickness symptomatology (NAVTRASYSCEN TR-87007)|date=1987|publisher=Naval Training Systems Center|location=Orlando, FL}} In more recent research, there is some disagreement as to whether gender or sex is a clear factor in susceptibility to virtual reality sickness.{{Citation|last=Lawson|first=Ben|title=Motion Sickness Symptomatology and Origins|date=2014-08-13|work=Handbook of Virtual Environments|pages=531–600|publisher=CRC Press|doi=10.1201/b17360-29|isbn=978-1-4665-1184-2}}{{Cite journal|last1=Saredakis|first1=Dimitrios|last2=Szpak|first2=Ancret|last3=Birckhead|first3=Brandon|last4=Keage|first4=Hannah AD|last5=Rizzo|first5=Albert|last6=Loetscher|first6=Tobias|date=2019-12-13|title=Factors associated with virtual reality sickness in head-mounted displays: a systematic review and meta-analysis|doi=10.31234/osf.io/7u4hn|doi-access=free}}
• Health: Susceptibility to virtual reality sickness appears to increase in people who are not at their usual level of health, suggesting that virtual reality may not be appropriate for people who are in ill health. This includes people who are fatigued; have not had enough sleep; are nauseated; or have an upper respiratory illness, ear trouble, or influenza.{{cite journal|last1=Parker|first1=D. E.|last2=Harm|first2=D. L.|title=Mental rotation: A key to mitigation of motion sickness in the virtual environment?|journal=Presence|date=1992|volume=1|issue=3|pages=329–333|pmid=11538019|doi=10.1162/pres.1992.1.3.329|s2cid=8035336}}
• Mental rotation ability: Better mental rotation ability appears to reduce susceptibility to virtual reality sickness, suggesting that training users in mental rotation may reduce the incidence of virtual reality sickness.
• Field dependence/independence: Field dependence/independence is a measure of perceptual style. Those with strong field dependence exhibit a strong influence of surrounding environment on their perception of an object, whereas people with strong field independence show a smaller influence of surrounding environment on their perception of the object. While the relationship between field dependence/independence and virtual reality sickness is complex, it appears that, in general, people without a strong tendency towards one extreme or the other are most susceptible to virtual reality sickness.
• Motion sickness sensitivity: Those who are more sensitive to motion sickness in reality are also more sensitive to virtual reality sickness.

The subjective sickness questionnaire (SSQ) is the most widely used for measuring the subjective level of cybersickness. It consists of sixteen items associated with cybersickness and employs a straightforward scoring approach to evaluate the severity of discomfort.

{{cite journal

| last1 = Yeo

| first1 = Sang Seok

| title = Investigating cortical activity during cybersickness by fNIRS

| journal = Scientific Reports

| volume = 14

| year = 2024

| doi = 10.1038/s41598-024-58715-2

| url = https://www.nature.com/articles/s41598-024-58715-2

| access-date = 2025-01-05

| pmc = 10998856

}}

• Immersion (virtual reality)
• Screen-door effect
• Vestibulo-ocular reflex

{{Reflist|2}}

{{Mixed reality}}

{{Motion sickness}}

Category:Virtual reality

Category:Motion sickness