The Role of Audio in Triggering Motion Sickness

As a disabled gamer and accessibility consultant, when I talk to game developers about the barriers that I experience when playing video games, I will often get asked “Which of your disabilities is the biggest barrier to your ability to play video games?”

While the answer to that question might differ from one day to the next, if pressed for an answer I will frequently point to my experiences with chronic motion sickness, often to the surprise of the developer in question.

Chronic Motion Sickness is often treated as a minor accessibility barrier by game developers who don’t have first hand experience of the condition. A lot of my job over the past few years as a consultant has involved explaining the ways that chronic motion sickness can be debilitating when triggered, how frequent exposure to triggers can make the condition worse long term, why “powering through” can do more harm than good for a player, and the motion sickness triggers that developers are unaware may be hiding in their games.

Simplifying the condition, motion sickness is triggered when there is a mismatch in data between your vestibular system and your other senses. Your vestibular system is basically some fluid in your ears that helps you to sense movement. If your vestibular system feels movement but doesn’t see it (such as looking at stationary text on your phone while in a moving car) you may start to feel ill as your body assumes that one of its senses is not responding correctly and tries to alert you to that mismatched stimuli.

The reverse of the above is also true, and is more commonly why people feel motion sick when gaming – If you see first person movement with your eyes, but don’t feel that movement in your vestibular system, that mismatch is what triggers a bout of motion sickness.

The thing is, in all of the descriptions I have so far given of motion sickness, I’ve described a mismatch between what your eyes see and your vestibular system feels being the cause of the issue. It is a major factor in contributing to motion sickness, but it’s not the full story.

Motion sickness can also be triggered, or reduced, by non visual sensory information.

A great example of this, and one that I rarely see discussed, is the role of audio design in triggering motion sickness.

Recently myself and my Ctrl, Alt, Access co-host Arevya have been playing through a game called Powerwash Simulator 2. It’s a fantastically fun game, but one that we both had motion sickness issues with while playing. Some of our issues were caused by camera sensitivity when playing with a controller, and part of it was to do with visual effects in first person, but we both came to the conclusion that part of our issue was also to do with the game’s stereo audio.

For this particular game, audio panning rapidly from left to right as the first person player moved the pointer location of their jet washer was contributing to the onset of motion sickness when playing. We were hearing movement in directional audio, but not feeling movement in our vestibular system. The mismatching sensory data was coming from what we were hearing as much as what we were seeing.

Motion sickness triggers in audio are less frequently researched than visual triggers, and as such a lot of the advice that I have for developers in this regard is pieced together from my own personal experiences as a player with chronic motion sickness issues. This is not a comprehensive list that will guarantee your game not triggering motion sickness via audio, but it is some best practices worth considering. A dedicated accessibility assessment of your specific game is likely to catch issues that this broadly presented advice may miss.

First and foremost, allow your players to set game audio to mono wherever able, particularly with first person games, even moreso if those are designed to be played with headphones on. If your first person game requires directional audio to be playable it’s already going to be inaccessible for players with various kinds of hearing loss for example, so consider alternative ways to communicate audio directions such as closed captions with directional indicators. These will make your game more accessible for players with hearing loss, and also make playing with mono audio an option that you can offer motion sickness prone players.

Not all audio is equally likely to trigger motion sickness. Audio that pans rapidly from one side to another, particularly audio of things moving quickly near the centre point of the audio map, tend to cause these issues more frequently. Additionally, audio constantly moving in one direction across the audio landscape, such as the sound of rain and wind moving from left to right across the player for prolonged periods, can be more common motion sickness triggers in my experience.

Audio and visual design are intrinsically linked as motion sickness triggers. If your visuals and audio don’t move at the same speed as each other during rotations, or aren’t properly in sync, this very much exacerbates a lot of these issues.

In VR games in particular, audio design not matching with what is being seen or felt is a major issue. If your game for example is a first person VR game where the player is sat in a moving vehicle, being able to disable the audio of the vehicle’s rumbling engine may help to reduce motion sickness, as it reduces the sensory input types that are reinforcing the mismatch from movement not being felt.

Providing the feeling of motion in a way that syncs up with audio, such as rumble capable VR headsets vibrating to match the sounds of a rumbling vehicle, or to a lesser extent controller rumble, may help to reduce motion sickness symptoms in some scenarios.

While it’s hard to nail down hard and fast rules on how to fully prevent motion sickness onset that will apply to every single type of video game, a good way to think about motion sickness triggers is by taking a big picture look at the ways that players like myself have found to reduce its prevalence while gaming, outside of game specific settings solutions.

One of the best ways I have found to reduce the onset of motion sickness when I play first person games is to have cold air on my face, either by opening a window in the winter or blowing a powerful fan at my face. The sensation of air moving past my face is often enough to trick my vestibular system. I can feel a sensation that I usually only feel when I’m moving. Maybe the movement visuals and audio I’m experiencing are okay?

The best ways to reduce motion sickness while gaming are in many cases either reducing the sensory input that’s telling your eyes and ears that you’re moving when you’re not, or increasing the input to your touch and vestibular systems to convince them that you are moving. While vibrations can help somewhat with emulating the feeling of movement, anything you can do to reduce the intensity of the signals telling your eyes and ears that they’re moving can equally help. That’s why mono audio, audio sliders, and the ability to turn off problem sound types, alongside ensuring your audio and visuals are well synchronised, is so important to helping reduce motion sickness.

A lot of people write off motion sickness as not a big deal, but it’s a condition that often gets more intense and easier to trigger the more times you try to push through and ignore it. I’ve more than once been rendered unable to work for multiple hours by a particularly bad bout of motion sickness, with lingering effects for days afterwards. 

It can be truly debilitating, and makes certain games literally impossible for me to complete playing. For me it is a hard barrier to game progression, and I would love to see more game developers take the time to consider the role that their game’s audio design might have on worsening illness in motion sickness prone players.