We still don’t understand motion sickness | Hacker News Reader

We still don’t understand motion sickness

qz.com

69 pointsswingline-74732 comments

This is a topic close to my heart. Ever since console gaming went 3D I realised I can't look at anything from a first person perspective without feeling violently ill.

The effect takes hold quicker if I'm looking at someone else playing but even when it is me controlling the action I will be ill within minutes. If I let it get to that point the only solution is to go to a dark room and lie down for an hour or more.

I sometimes joke about it, but in reality I do worry about a future of HUDs and VR environments.

From the two available theories I find the Sensory Conflict Theory the more compelling although I'm still not convinced they have entirely cracked it.

Along with gaming I get similar effects from 3D movies. I struggle to understand the postural challenge that comes from watching a 3D movie vs a 2D movie in the same cinema seat. From my lay persons perspective it would seem to have more to do with the ability of my eyes/brain/inner ear processing more information simultaneously and making contextual sense of it.

Would you happen to have epilepsy? My girlfriend also has trouble looking at first person shooters and third person shooters. It gets her dizzy and nauseous. She has epilepsy and apparently it feels similar to the post-seizure aura.

Not that I'm aware of. At least I don't think I've ever shown any signs of epilepsy and certainly have never been diagnosed with it.

I've mentioned the 'motion' sickness issue to my GP in the past but it was dismissed as nothing very serious. On the one hand I understand as I can avoid the triggers relatively easy but equally its troubling to know something so innocuous can make me feel so sick.

>The effect takes hold quicker if I'm looking at someone else playing

Totally understand this. I refuse to watch people's vacation videos because the unpredictable zooming and panning makes me sick.

The author's theory doesn't account for motion sickness while sitting or even completely still looking at a video game/VR. Why doesn't the article make any attempt to address this? I'm not finding it convincing at all.

I think it's beyond stupid. Most people know exactly what neurotoxin induced vertigo feels like -- did the author ever drink any alcohol? The whole world is spinning, you get sick even when lying perfectly still. It's not motion that causes the sickness, it's your brain detecting messed up responses from the vestibular system.

Also, why else would this reflex exist? Throwing up is very, very costly in terms of calories, and for much of our evolutionary history, food was scarce. Such an extreme measure could only have evolved when the alternative was even worse.

In the case of alcohol the spinning is mostly due to differences in the density of the liquid inside the cilia of your inner ear cells when alcohol gets in and out of them, specially in the second case (some hours after drinking). It's really an alcohol-specific effect. Some other toxins might induce vertigo through other mechanisms though.

Normally mixed up signals are a sign of having eaten something poisonous. So barfing is a reasonable evolutionary response.

Motion sickness is definitely strange.

I flew for the first time a few months ago (typical commercial flight) and when taking off while simultaneously making a turn, it felt like my stomach was in my shoes and really messed with me. Nothing was spinning but it felt very unpleasant and unsettling. It's now happened 3 times since then.

Laying way back in a dental chair also causes me to feel dizzy to the point where they always have to put me at a steeper angle, especially my neck / head.

When trying to fall asleep, I would say like 2% of the time I will get a weird feeling and I feel forced to sit up and find an object in the room to get oriented. That one is really crazy because it feels like things are spinning but it goes immediately away when I see anything in the room.

However, if I lay back on a floor I can deal with it for a few minutes, but I always feel dizzy when I get up. I also hate the feeling of having my head lower than my body too. Like laying half on a bed with my head near the floor. Doesn't make me dizzy but it feels like a massive amount of head rush pressure. I see people doing situps upside down, long handstands and being on those flip boards so I have to think what I feel is not normal. Not sure if it's all related.

I have no problems in cars, trains, boats, playing FPS games, bobbing cameras, etc.. I also enjoyed roller coasters but I haven't been on one in like 20 years so who knows now.

To add to the mystery, why do people get less motion sickness when they are not just passengers, but drive their car or a boat?

If you look outside, you are much less likely to get motion sickness vs, for example, looking down at your phone. I get to try it every time I go to a theme park, on a fast rotating ride, if I look inside, I get dizzy and sick, but looking outside makes you resilient.

Yes. Also the driver can anticipate the various accelerations more accurately than the passengers since he is causing them.

As a passenger I find I can read in reasonable comfort if I can look up and out of the vehicle at each acceleration i.e. at turns, when stopping/starting.

The "neurotoxin response" theory that the author doesn't like would say that this is because you anticipate the movements perfectly because you're the one causing them.

This.

I used to take a coworker on kamikaze night runs up and down the california coast in my track car. He would envision he was driving to avoid motion sickness. Imagining braking, steering, blipping the throttle, shifting gears, operating the clutch, everything as if he were playing a video game.

One night I decided to test it and started driving poorly, braking early for turns, picking the wrong gear, or just not accelerating hard out of the corners.

He became angry and sick immediately, we had to keep pulling over for him to vomit. It was uncanny, we had been doing this stuff every weekend for months without any motion sickness issues ever. The moment I started driving unpredictably - it wasn't even driving poorly, just not what he expected, he fell apart.

I do this as well and it doesn't always work like you described. Unexpected breaks are the worst. I also feel less sick if I am sitting/standing sideways to the direction of motion. Somehow I don't feel motion-sickness at all on water, air or trains, but just on road.

Most taxi rides give me a strong motion sickness, while regular car rides do not. My assumption is this is due to the more aggressive and unpredictable driving style (quick, unexpected lane switches and turns), so I think this more or les correlates with your coworker's experience.

This leaves something to be desired -- it's very difficult to tickle yourself with your own fingers, but easy with a feather, even though you know you're doing it.

The act of tickling yourself is a two-way sensory exchange. You feel your fingers and your fingers feel you, whereas with a feather you don't have the latter.

By comparison, it's also easy to tickle the roof of your mouth with your own tongue.

It is, because when you are steering, you have much less sensory conflict. You hold the steering wheel, which gives you input about e.g. the cars motion, and even more, you are actively guiding or causing the cars motion, both with steering wheel as well as with gas and brake pedal.

I've been able to get motion sick while driving in traffic.

Not entirely related, many FPS games trigger motion sickness in many people, some find an improvement after modifying the field of vision, but many don't.

I was severely affected by this. However as a teenager I was able to slowly build a tolerance. At first I could play for about 15 minutes before feeling very sick and having to lay on the bed. After a couple weeks I could play for as long as I wanted.

I get similar symptoms under two very specific circumstances - when sitting in a car being driven by someone else in the morning I easily end up horribly nauseous, and when lying in bed at night with a pillow that doesn’t elevate my head enough, I’ll wake up in a terrible nauseating death spin of vertigo. Two of the very worst feelings I’ve ever had.

That nauseating spin sounds like benign paroxysmal positional vertigo (BPPV), caused by displaced inner ear crystals. You might want to research the Epley maneuver and similar and talk to your doctor - it's a trivial procedure that might fix that.

I thought the displaced inner ear crystals would cause chronic vertigo rather than paroxysmal positional vertigo. At least from my experience with my mother. Sudden falling sensation, and her trying to hold onto the arms of her chair as if she is free-falling even though she is sitting down.

What he is describing sounds to me more similar to how I feel when I often feel lying down on my back and under the influence of Cannabis. Turning to my side immediately fixes it without exception. It isn't necessarily a falling sensation but rather just nausea and the world starting to spin and accelerate, until you turn. And I do not have this when I am sober.

> But he notes that people who lack a vestibular system—something that can happen through disease—simply don’t get sick

But doesn't this go against his own theory?

As someone who is strongly affected by motion sickness all my life, I would unfortunately consider myself as a kind of expert on the topic. I would like to list a few of my observations on the topic. I hope it is informative or even helpful. As a physicist, I am not a medical expert, but at least a careful observer.

- I am extremely sensitive. Sometimes driving as little 3 miles as a passenger in a car make me sick.

- I have no doubts that motion sickness is caused by the sensoric mismatch between the eyes and the sense of equilibrium. Other sources of sensorical input play a role though (you can sense a vehicles motion with your butt for example).

- as the driver I get much less motion sick than as a passenger. Under normal circumstances I don't get motion sick while driving, but unfortunately it happens from time to time. Bad traffic, darkness, empty stomach seems to be causes there. As the driver, I not only have the additional feedback through the steering wheel, but also I am the main guide of the motion of the car. Accelleration and decellaration are directly caused by me, same with turning into curves.

- the nauseating effect is strongly coupled to the frequency of the motion. There was a link on HN some years ago to a paper which claims the maximum is at 5hz (I might misremember the number). This matches my experience well. I notice a strong dependency on the speed of the car. About 80kph (50mph) seems to be the worst. Going faster usually is easier on my stomach. Equally, I like stiff suspensions, soft ones are killing me. (Strangely, I never got sick in an Audi yet).

- same applies to some extend to boats. Yes, in my youth I acquired a sailors license, consider me crazy. Cruising against the wind is much less a problem than on rear wind courses.

- of course, I can't read in a vehicle.

- when I get truely sick, my stomach is off for hours, if not even till the next day. I think the theory that the body reacts to an imagined poison sounds very plausible.

- I do get motion sick in basically any vehicle. In trains much less than in busses, but even in trains I can feel uncomfortable. In both cases, it helps a lot to stand and not sit in the vehicle. You get the additional sensorical input from your feet (the sensor input of the feet plays the major role in the ability to stand upright and walk) and of course your hands holding to a grip. The effort for the brain to keep standing seems to be very helpful in convincing it of the real motion going on.

- I can watch 3D movies in cinemas. Only rarely I get a minor nausea which passes quickly. I have severe difficulties playing first person 3D games on the computer. Seems my brain can distinguish those cases.

- another strong point towards the irritation theory: I am rather sensitive to scrolling on a computer. With the first optical mice, I got quite regularly sick, as their motion on the screen not always followed the motion of the mouse. Those problems have vanished with later generations of optical mice. Erratic scrolling or screen reactions can still make me quite sick.

- in general, having lots of fresh air helps somewhat in not getting sick.

- there are of course psycological factors. But it has certainly nothing to do with "fear". I actually get less sick when a car drives fast (>70mph) as long as the driving isn't too erratic. Its the frequency of the motion. You do of course get quickly sick, if you start listening for symptomes. So please, don't ask someone who is sensible to motion sickness whether they still feel well... A mild distraction can help, a strong distraction, distracting from noticing the motion can be counterproductive. I usually like listening to conversations, participating can be a risk.

- motion sickness causes apathy. So if you know someone being sick, watch them. They might run into a car, fall from the boat and not care.

- sometimes it does help to lie down and close the eye. This can reduce the irritation as it takes the eye input out of the game, and your back provides additional sensoric input.

On the prevention side, if I want to travel except when I am doing the driving, e.g. air travel, I had the best results with Cinnerazine. Taking a single capsule of 75mg per day, at least 3 days in advance of the travel and continuing during the whole travel time has great results. This allows me, with some care, to use modern means of transport like a normal person. I am not totally immune, a colleague driving me up to Alices and La Honda from San Jose made me feel pretty bad, but I recovered reasonably well, though I felt uncomfortable for the rest of the trip. On the other side, I noticed me once texting on the back seat of a cab racing through Taipei, without any discomfort. YMMV.

I would be happy to answer any questions. As said in the beginning, I am not a medical professional, in doubt please ask a doctor, I just have tons of experience on that matter.

I'm not sure if you are aware of the recent "anti-motion sickness glasses":

https://visuall.net/2018/07/09/seetroen-the-first-glasses-to...

Maybe you could test them, for science.

I have seen a notice about them. I am quite sceptical though, that they would have a significant effect.

I get motion sick in tall buildings. It sucks.

Having experienced vestibular dysregulation, which included rapid, transient vertigo, headache, delirium and nausea upon moving one's eye too fast, I would suspect it's related to genes or epigenetics of the vestibular system.

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