Researchers have developed a vibrating platform that could reduce the effects of cybersickness for some virtual reality users, addressing an increasingly urgent problem as VR becomes more prevalent in education, art, entertainment and communications.
The study, published March 24 in IEEE Transactions on Visualization and Computer Graphics, was conducted at the University of Canterbury's Human Interface Technology (HIT) Lab, an interdisciplinary space for game designers, graphic artists and digital developers to create human-centric virtual and augmented reality systems as well as other computer-based interfaces.
Cybersickness can induce symptoms similar to motion sickness, including nausea, migraines, dizziness and mental fog. For some, these physiological and mental issues can persist hours after the experience has ended. Some researchers think that these symptoms might be mitigated by providing additional stimulation to users.
"The major feedback in virtual reality is visual and the audio only," Sungchul Jung, a postdoctoral fellow at the HIT Lab and the study's lead author, told The Academic Times. "So we have to provide the secondary feedback: tactile, olfactory and even taste."
The team's digital simulation placed 22 users in the passenger seat of a truck that made laps around a realistic dirt path, with a virtual driver steering beside them. In real life, the participants were equipped with a VR headset and seated on a chair that was placed on a vibrating platform.
The platform delivered pulsed radio waves, similar to how a speaker's subwoofer might shake nearby surfaces, in order to provide a tactile response that would replicate the shaky feeling of driving along a dirt road. In order to ensure that their vibrating floor sufficiently replicated the real-world experience, the team conducted field tests in a real truck to track its average vibration intensity.
After experiencing both the vibration and non-vibration versions of the virtual ride, all of the participants said they preferred the vibration experience. Oculomotor readings, which measure subjective levels of eye strain, were also significantly lower in vibration participants.
Physiological data appeared to somewhat support these subjective preferences. Volunteers' galvanic skin response levels — an indication of the intensity of one's emotional state — were significantly lower in the vibration tests compared to those with no vibration. Other measures, like heart rate, were not significantly different between both groups.
Before the researchers could prove that their floor device might reduce undesirable VR-related side effects, they had to ensure that their simulation could induce cybersickness in the first place. They placed users in the point-of-view of a passenger, since vehicle passengers in the real world tend to experience more severe motion sickness compared to drivers. Passengers in both the vibration procedure and a non-vibration control test were asked to rate their level of discomfort at each 30-second mark throughout their trip. Both groups reported increasing levels of discomfort over the course of their trip, matching the researchers' expectations.
VR designers do not always have cybersickness in mind when developing new products. And higher degrees of realism can actually increase the level of cybersickness in some users, as the brain can become confused by subtle inconsistencies between the virtual world and the real world.
Scientists still aren't sure what causes cybersickness, but there are a few related theories that try to account for the phenomenon. Perhaps the most popular idea is that a conflict between multiple sensory inputs causes symptoms. If a VR experience asks a user to drive a car, for instance, she will see the car moving through a digital landscape but will not feel the inertia that usually accompanies a real-life car ride.
Some evolutionary biologists have suggested that those inconsistent sensory stimuli could cause nausea because the contradictory inputs that accompany VR usage are similar to what it feels like to be poisoned. The body's natural response, the theory posits, is to initiate feelings of nausea to help a person rid herself of neurotoxins, which could explain why some VR users feel especially sick after prolonged use. A related theory posits that cybersickness is caused by users adopting atypical postures that cause physical and mental strain.
The University of Canterbury study confined participants to a seated position, but the researchers are also interested in adapting their technology for standing or walking simulations. Future iterations of the platform could provide vibrational feedback as a user steps, giving them additional tactile responses for more comfortable VR experiences.
While some might believe that all-encompassing virtual experiences like the kinds in science fiction flicks will soon be a reality, Jung cautions that those types of multi-sensory worlds are still a long way off. That's why it's important, in VR's early years, to establish a better understanding of how cybersickness manifests and progresses in users, he said.
But in the same way that motion sickness cannot be totally eliminated from our lives, researchers say it's more realistic to consider how to best control and reduce the effects of cybersickness, rather than attempting to eliminate it altogether.
One participant became so sick and uncomfortable that she could no longer participate in the remainder of the study — a reminder, Jung said, of the wide degree of differences in users' physiological responses to virtual experiences. Researchers at the HIT Lab hope to create systems that will work for people with a wide array of sensitivities to make VR a more inclusive and accessible experience.
"The very important lesson from the project was, as we experience in real life in terms of motion sickness, the sickness level is very dependent on [participants'] gender, their age and their experience," Jung said. "Maybe cybersickness cannot be overcome 100%. But we want it to work at least at a similar level to how we deal in real life with motion sickness."
The study, "Floor-vibration VR: Mitigating Cybersickness Using Whole-body Tactile Stimuli in Highly Realistic Vehicle Driving Experiences" published March 24 in IEEE Transactions on Visualization and Computer Graphics," was authored by Sungchul Jung, Richard Li, Ryan Mckee and Robert W. Lindeman, University of Canterbury; and Mary C. Whitton, University of North Carolina.