By Emma Young
VR headsets are becoming commonplace not only in entertainment and pilot training, but in clinical settings — in helping people to overcome phobias, for example, or to distract burns patients while their dressings are changed. Unfortunately, there’s a common side effect: visually induced motion sickness (VIMS), sometimes also known as “cybersickness”. This limits the use of VR, or means that people have to spend extended periods feeling nauseous while they adapt to it. But according to new research in Experimental Brain Research there’s a very simple way to tackle this problem: chewing flavoured gum.
Mara Kaufeld at the Fraunhofer Institute for Communication, Information Processing and Ergonomics in Bonn, Germany and her colleagues studied 77 healthy adults, who each completed a 15-minute simulated search and rescue helicopter flight using a head-mounted VR set. One group was given peppermint flavoured gum to chew during the flight, a second was given ginger-flavoured gum, and a control group had no gum.
Before the flight and also afterwards, each participant completed a VIMS scale, which asked about various symptoms, including headaches, nausea and eyestrain. Every minute of the flight, they also reported verbally on any feelings of sickness. And the results were clear: chewing either of the gums led to significantly lower peak sickness scores while flying. The gum-chewers also reported less disorientation on the post-flight VIMS assessment.
What explains the findings? Both gums were deemed to have a pretty pleasant taste, but the team found that the higher the pleasantness ratings, the milder the VIMS symptoms. So perhaps positive emotions generated by the pleasant taste helped to combat feelings of sickness.
But the physical act of chewing was probably important, too. Motion sickness is thought to be caused by a mismatch between signals from the eyes and from the vestibular system, which senses head movement. If your eyes are telling your brain that you’re moving but your vestibular system is maintaining that your head is still — as in the case of a VR helicopter flight — this leads to nausea. (Why should the conflict trigger nausea? One theory is that because some poisons affect the vestibular system, the brain assumes that this is what’s happened — and you feel sick.)
But if chewing gum physically stimulates the mastoid region — a region of the skull just below and behind the ear — this could trigger vestibular signals, which the brain would recognise as unhelpful “noise”, rather than useful information about head movement. This could lead it to temporarily demote vestibular signals, and to rely more on what the eyes are saying, which would lessen the sensory conflict — and mean less VIMS. That’s the theory, at least. But it’s certainly supported by findings from other studies.
Unfortunately, the team didn’t include a group that was given flavourless gum, however, so they can’t tell how much of the reduction in VIMS was down to the pleasant taste of the gum, and how much down to the action of chewing. As they note, chewing might also work as a distractor, and reduce feelings of sickness in that way, too. But there’s also another potential mechanism: as we’ve reported before, rhythmic vestibular signals are calming — and perhaps this might have an effect, too.
Might chewing gum also help with non-VR types of motion sickness? Only more research will tell, as car-sickness, for example, involves a reverse conflict: the vestibular system is maintaining that the head is moving — while for someone who is reading, or watching a screen, the eyes are saying that the body is still.
For now, though there are other ways to address VIMS, they all have downsides, the team argues. “Our results validate the use of chewing gum as an easy-to-use countermeasure against VIMS with great acceptance and entirely free of the side-effects associated with more potent medications,” they write. This is also one of those rare conclusions that no one has to wait for a new pill, product or carefully designed intervention to potentially benefit from. If you need to use VR at work, or elsewhere, it’s hard to think of a reason not to give gum a try.