Explaining Motion Sickness

Summary: Researchers explore different theories as to why some people are prone to experience motion sickness while traveling.

Source: The Conversation

If you’re someone who suffers from motion sickness, traveling in many types of vehicles can be difficult thanks to a host of symptoms like dizziness, lightheadedness, nausea and even vomiting. But it’s not completely clear why some people can read and play games on their phone during a long drive while others spend the journey desperately trying not to be sick. Nor is it clear why some people only experience motion sickness in certain types of vehicles and not others.

But there are two theories that might help explain what’s going on.

The sensory conflict theory proposes that a key player in motion sickness is our balance system. Balance is not maintained by just one single sensory organ. Rather, it combines what we’re seeing and feeling with information from the balance organ in our inner ears, which helps our balance system work out exactly where we are.

If the information from our eyes, inner ears and touch or pressure senses doesn’t match up, it can make us feel off-balance or unsteady. This is why it’s thought that motion sickness is caused by a mismatch of information from our senses – with our eyes and inner ear telling our body that we’re moving, even though we’re actually sitting stationary.

This is also why the less sensory mismatch we experience in a vehicle, the less likely we are to experience motion sickness. For example, travelling in a car on a smooth, straight road will cause less sensory mismatch than travelling on a winding road with lots of potholes.

This theory is currently considered the strongest explanation for motion sickness – though we’re still trying to understand the brain mechanisms that cause motion sickness.

An alternate (but related) theory suggests that it’s all down to controlling posture. According to this theory, motion sickness doesn’t happen just because of the mismatch of sensory information. Rather, it’s our inability to adjust our posture to reduce this mismatch of sensory information that makes us feel nauseous. While this makes sense – especially since we can’t always move around when travelling – there isn’t much evidence to support this theory.

No single reason

Motion sickness affects people differently, and there’s no single reason why some people experience motion sickness more frequently than others. But differences in how well a person’s vision and balance systems work will affect how they may feel in different types of vehicles. Certain disorders – including migraines and inner ear diseases, such as Ménière’s disease – increase the likelihood of experiencing motion sickness. 

Age and sex may also affect likelihood of experiencing motion sickness – with some research suggesting experiences peak around nine or ten years of age, and are more common in women. However, it is uncertain as to why this may be the case.

The type of vehicle people travel in will also have some affect on the amount of motion sickness a person may experience. Broadly, any factor that increases the mismatch between each of the senses that contribute to our balance system will increase the risk of motion sickness. The longer the experience lasts and the larger the size of the movement, the worse the symptoms.

For example, traveling on a small boat in a storm for more than eight hours will cause quite severe symptoms – whereas a one-hour train journey will probably have little effect, even if the track isn’t perfectly smooth.

Many people also report experiencing motion sickness when they’re a passenger – not when they’re driving a vehicle. This is probably because drivers are (unsurprisingly) much better at anticipating the motion of a vehicle and move their bodies according to the movement of the vehicle.

For example, if a car travels around a sharp bend, the driver is going to be looking ahead and anticipating the movement of the car as they turn – while a passenger is likely to react as the turn happens by leaning in the opposite direction.

This shows a woman covering her mouth, sitting in the back of a car
Motion sickness affects people of all ages. Credit: The Conversation

Motion sickness also isn’t limited to the “real world”, with cybersickness another type of motion sickness that people get from the virtual environments, often when playing video games. This likely happens because of the sensory conflict of seeing the environment move on the screen while the body remains stationary. Watching films in 3D at the cinema can prompt motion sickness for the same reason.

If you’re someone who suffers from motion sickness, the best thing to do the next time you’re in a vehicle is try to reduce the mismatch of sensory information. So avoid reading in the car – as this causes a mismatch between what we’re seeing and what we’re feeling – and try to instead look out the window. This may help reduce nausea as the visual information now better matches the balance information in our the inner ear. The same is true for boats and trains – focusing on the passing landscape can reduce symptoms.

Other tips to reduce motion sickness include not having a heavy meal before travel, ventilating the vehicle and taking regular stops (when possible). But if these tips aren’t enough to tackle symptoms, using an anti-motion sickness medication may help. These reduce activity in the balance system of the brain or reduce the number of signals the brain sends to the gut, which can help to stop nausea and vomiting.

About this motion sickness and neuroscience research news

Author: Saima Rajasingam
Source: The Conversation
Contact: Saima Rajasingam – The Conversation
Image: The image is credited to The Conversation

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  1. Different causes will generate different results. Motion sickness is caused by axis rotation,visually induced and low-frequency noise three main causes, with completely different symptoms. The corresponding axis rotation may cause symptoms of the most awful dizziness, visually induced may cause mild dizziness, and low-frequency noise may cause nausea, vomiting, and drowsiness. That is to say rumbling low frequency noise may cause carsickness, seasickness, and airsickness.
    Carsickness and seasickness are caused by a special kind of rumbling low-frequency noise. Therefore, people with good low-frequency hearing are easy to get carsick and seasick, and deaf people who can’t hear low-frequency sound will not get carsick and seasick at all.Women can hear better than men, so women tend to suffer from carsickness more than men.Drivers or aviators long-term exposure to car Low frequency noise or after repeated exposures to the flying environment.will cause a temporary neurosensory low frequency hearing loss. Therefore, the driver or aviators will not get carsickness or airsickness.Airsickness or carsickness may also occur when a previously adapted individual returns to duty after a period of non-flying.This is because low-frequency hearing has been restored.People who gets carsickness in a car usually can travel in trains,metro,trucks,tractors,motorcycles that can’t hear low-frequency noise without any discomfort at all.Also, even when people are standing near an airplane rather than riding on the airplane, the stimuli from the low-frequency rumbling of the airplane’s motor still triggers intense airsickness or carsickness.
    There are many patterns of hearing loss. Generally clinicians group them along several axes; sensory vs conductive; the severity axis — mild vs moderate vs. profound; the time axis — sudden vs progressive vs chronic, and the frequency spectrum that is affected. Roughly speaking, the frequency patterns of hearing loss are divided up into: Low-frequency, mid-frequency, high-frequency, notches, and flat. Among them, only the deaf people with low-frequency hearing loss will not get carsick and seasick. Deaf people with other types of hearing loss will still get carsick and seasick.
    In addition, because medical experts define dizziness (dizziness due to spinning)and carsickness as motion sickness, all the deaf people without long-term spinning training will experience motion sickness(dizziness due to spinning) in a spinning chair .
    Symptoms of carsickness get stronger when vehicles bump or shake more frequently, which is just a coincidence. It is just because low-frequency noise gets louder when bumping and shaking gets more serious. Without such low-frequency noise, people will not feel carsick no matter how hard the car bumps or shakes. For example, people get carsick on trains or subways running at the same speed when hearing low-frequency noise. Without such noise on trains or subways, carsickness can be avoided. It fully proves that low-frequency noise is the only reason that causes carsickness.
    Scientific theories can also be testable and make falsifiable predictions.If any evidence can be cited to prove that deaf people who can’t hear low-frequency sound also get carsickness yet can avoid it by not riding any vehicles, this opinion can be invalidated. In reality, however, pseudoscience cannot be falsifiable predictions. For instance, a pseudoscience opinion that carsickness is caused by visual motion stimulation cannot be overturned by the fact that the blind still gets carsicknes.
    The symptoms caused respectively by the rotational and carsickness are quite different. The dizziness due to spinning, while carsickness usually causes nausea or sleepiness.All experiments of motion sickness can only simulate the symptoms of carsick or seasick, but can not replicate the symptoms of carsick or seasick. This is why authors of many scholar articles only state that the rotational are associated to carsickness, but the reasons behind carsickness are still unknown. Only unreliable knowledge popularizing articles say that the reason of carsickness is the rotational. This is not true. Actually, the rotational are not related to carsickness, which is actually caused by a special low-frequency noise. Only this kind of noise can cause exactly the same symptoms of carsickness. Even if the pilot without staying on the airplane, the noise of airplane engine can also cause symptoms of carsickness or airsickness. For example, Fifty years ago, more or less, Republic Aviation built a turboprop jet fighter based on the F84. It was designed to be transonic and the design propellor tip speed was supersonic. During ground tests of full power and prop RPM it was discovered that every member of the ground crew was rendered violently nauseous by the resulting high frequency ( beyond normal hearing range ) noise.Experts of carsickness around the world all know that only noise can cause exactly the same symptoms of carsickness, but they fraud people by saying that this phenomenon is only a psychological reaction!
    The reason for this scientific hoax is medical experts’ lack of knowledge about acoustics. They have only noticed that the tractor doesn’t cause motion sickness although it is rather noisy, so they have wrongly concluded that motion sickness doesn’t result from noise. In fact, they haven’t discerned that the noise of a tractor differs from the low-frequency noise which brings about motion sickness. Although they couldn’t figure out the cause of motion sickness, they were too hasty to reach a conclusion. As a consequence, they have scientifically tricked people that motion sickness is associated with many factors such as axis rotation, movement and visual motion.

  2. Also ginger seems to work good with my girlfriend. (The candied version is liked most).. as an alternative to lab made medicine. Probably has mentioned effects.

  3. I have suffered from motion sickness most of my life and have found that the wrist bands help a lot. Some called Sea Bands, why do they work? How does the pressure from the little ball help.

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