Motion sickness

Other names, travel sickness, seasickness, carsickness, simulation sickness, space motion sickness.

Nearly all people with sufficient motion will suffer motion sickness.

Roughly one-third of people are highly susceptible to motion sickness.

Around 80% of the general population is susceptible to cases of medium to high motion sickness. 

Motion sickness occurs due to a difference between actual and expected motion. 

Symptoms commonly include, cold sweat, headache, tiredness, loss of appetite, and increased salivation.

Complications may rarely include dehydration, electrolyte abnormalities, or a lower esophageal tear.

The cause of motion sickness is either real or perceived motion. 

This may include car travel, air travel, sea travel, space travel, or reality stimulation.

Risk factors include pregnancy, migraines, and Ménière’s disease.

The diagnosis is based on symptoms.

Treatment may include behavioral measures or medications. 

Behavioral measures include keeping the head still and focusing on the horizon.

Three types of medications are useful: antimuscarinics such as scopolamine, H1 antihistamines such as dimenhydrinate, and amphetamines such as dexamphetamine.

Side effects, however, may limit the use of medications.

A number of medications used for nausea such as ondansetron are not effective for motion sickness.

Nearly all people are affected with sufficient motion.

Most people will experience motion sickness at least once in their lifetime.

Susceptibility to motion sickness is variable, with about one-third of the population being highly susceptible while most other people are affected under extreme conditions.

Women are more easily affected than men.

Symptoms commonly include nausea, vomiting, cold sweat, headache, dizziness, tiredness, loss of appetite, and increased salivation.

.Occasionally, tiredness can last for hours to days after an episode of motion sickness.

Rarely severe symptoms such as the inability to walk, ongoing vomiting, or social isolation may occur while rare complications may include electrolyte abnormality, dehydration or a  esophageal tear from vomiting.

Motion sickness is divided into three categories:

Motion sickness caused by motion that is felt but not seen-terrestrial motion sickness;

Motion sickness caused by motion that is seen but not felt-space motion sickness

Motion sickness caused when both systems detect motion but they do not correspond i.e. either terrestrial or space motion sickness.

Carsickness is quite common and evidenced by disorientation while reading a map, a book, or a small screen during travel. 

Carsickness is the result the sensory conflict arising in the brain from differing sensory inputs. 

Motion sickness is caused by a conflict between signals arriving in the from the inner ear, which forms the base of the vestibular system, the sensory apparatus that deals with movement and balance, and which detects motion mechanically. 

Looking at a stationary object within a vehicle, such as a magazine, eyes will inform their brain that what they are viewing is not moving. 

The inner ears, however, will contradict this by sensing the motion of the vehicle.

This creates conflict between the eyes and inner ear. 

The  eyes mostly visualize the interior of the car which is motionless while the  vestibular system of the inner ear senses motion as the vehicle.

Carsickness is worse when looking down, but may  be improved by looking outside the vehicle.

Air sickness is a kind of terrestrial motion sickness induced by certain sensations of air travel.

It is a form of motion sickness and is considered a normal response.

It is essentially the same as carsickness but occurs in an airplane. 

An airplane may bank and tilt sharply, and unless passengers are sitting by a window, they are likely to see only the stationary interior of the plane due to the small window sizes and during flights at night. 

Another factor is that while in flight, the view out of windows may be blocked by clouds, preventing passengers from seeing the moving ground or passing clouds.

Therefore, the effect is worse when looking down but may be lessened by looking outside of the vehicle.

Seasickness is a form of terrestrial motion sickness characterized by a feeling of  and, in extreme cases,  experienced after spending time on a boat. 

It is essentially the same as carsickness, though the motion of a watercraft tends to be more regular. 

Seasickness is typically brought on by the rocking motion of the craft or movement while the craft is immersed in water. 

As with airsickness, it is difficult to visually detect motion even if one looks outside the boat since water does not offer fixed points with which to visually judge motion. 

The greatest contributor to seasickness is the tendency to seek refuge below decks, where they are unable to relate themselves to the boat’s surroundings and consequent motion. 

Some people with carsickness are resistant to seasickness and vice versa.

Adjusting to the craft’s motion at sea is called “gaining one’s sea legs.

It can take a significant amount of time spent at sea after disembarking to regain a sense of stability known as  “post-sea legs”.

Rotating devices such as amusement park rides can cause motion sickness in many people.

When one spins and stops suddenly, fluid in the inner ear continues to rotate causing a sense of continued spinning while one’s visual system no longer detects motion.

Motion sickness in virtual reality (VR) occurs when there is a discrepancy between the visual perception of movement that VR provides and the body’s physical sensations: This mismatch can lead to symptoms such as nausea, dizziness, and disorientation.

Factors contribute to motion sickness in VR, including:

Latency: a delay in the VR display’s response to a user’s movement, it can disrupt the synchronization between visual and physical cues, leading to discomfort.

A narrow field of view in VR can create a tunnel-like effect that may increase the likelihood of motion sickness.

Rapid or exaggerated movements in VR, such as fast turns or jumps, can exacerbate motion sickness symptoms.

Motion sickness arising from such situations has been referred to as visually induced motion sickness(VIMS).

Zero gravity interferes with the vestibular system’s gravity-dependent operations, so that the two systems, vestibular and visual, no longer provide a unified and coherent sensory representation. 

Zero gravity causes unpleasant disorientation sensations often quite distinct from terrestrial motion sickness, but with similar symptoms. 

Zero gravity causes symptoms that may be more intense because a condition caused by prolonged weightlessness is usually quite unfamiliar.

Space motion sickness is aggravated by being able to freely move around, and so is more common in larger spacecraft. 

Terrestrial motion sickness is prevalent when susceptible people are watching films presented on very large screens such as , but may also occur in regular format theaters or even when watching TV or playing games. 

IMAX and other panoramic type theaters often show dramatic motions such as flying over a landscape or riding a motor cycle.

This type of motion sickness can be prevented by closing one’s eyes during such scenes.

Home movies, often filmed with a cell phone camera, also tend to cause motion sickness.

Using the zoom function seems to contribute to motion sickness.

Motion sickness due to  virtual reality is very similar to simulation sickness and motion sickness due to films. 

In virtual reality the effect is made more acute.

 In virtual reality all external reference points are blocked from vision, and in some cases stereo sound that may also give a sense of motion. 

The NADS-1 simulator is capable of accurately stimulating the vestibular system with a 360-degree horizontal field of view and 13 degrees of freedom motion base.

The exposure to rotational motions in a virtual environment can cause significant increases in nausea and other symptoms of motion sickness.

Moving within a rotating reference frame such as in a centrifuge or environment where with centrifugal force, causes a sense of motion in the vestibular system that does not match the motion that is seen.

Motions sickness pathophysiology hypothesis is by the sensory conflict theory referring to a discontinuity between either visual, proprioceptive, and somatosensory input, or semicircular canal and otolith input.

The brain is presented with two incongruous states of motion; the result is often nausea and other symptoms of disorientation known as motion sickness. 

Such conditions happen when there is not a synchronized and unified representation of one’s body and surroundings.

In the sensory conflict theory, the cause of terrestrial motion sickness is the opposite of the cause of space motion sickness. 

In  terrestrial motion sickness occurs when one perceives visually that one’s surroundings are relatively immobile while the  reports that one’s body is in motion relative to its surroundings: occurs when the visual system perceives that one’s surroundings are in motion while the vestibular system reports relative bodily immobility as in zero gravity.

The neural mismatch theory implies a mismatch occurring between ongoing sensory experience and long-term memory rather than between components of the vestibular and visual systems. 

This theory suggests the limbic system in the integration of sensory information and long-term memory, in the expression of the symptoms of motion sickness, and the impact of anti-motion-sickness drugs and stress hormones on limbic system function. 

The  nystagmus hypothesis based on stimulation of the  resulting from the stretching or traction of extra-ocular muscles co-occurring with eye movements caused by vestibular stimulation. 

With the exception of voluntary eye movements, the vestibular and oculomotor systems are thoroughly linked. 

Tenth nerve stimulation resulting from eye muscle stretch is proposed as the cause of motion sickness, explains why labyrinthine-defective individuals are immune to motion sickness; 

The diagnosis of motion sickness is based on symptoms.

Treatment may include behavioral measures or medications.

Behavioral measures to decrease motion sickness include:  holding the head still and lying on the back, focusing on the horizon, listening to music, mindful breathing, being the driver, and not reading while moving.

 A head-worn, computer device with a transparent display can be used to mitigate the effects of motion sickness: providing the wearer with digital reference lines in their field of vision that indicate the horizon’s position relative to the user’s head. 

 Medications for motion sickness

Motion sickness can be effectively managed with over-the-counter or prescription medications.

Antihistamines, work by blocking the action of histamine, a chemical ithat triggers symptoms of motion sickness.

Examples include dimenhydrinate (Dramamine), meclizine (Bonine), and diphenhydramine (Benadryl). 

They are available over-the-counter and are generally safe and effective for most people.

Scopolamine This prescription medication comes in a patch form that is applied behind the ear. 

It works by blocking receptors in the brain that trigger nausea and vomiting.

Promethazine a prescription medication that can be used to prevent motion sickness by blocking the effects of histamine in the brain.

Dextroamphetamine may be used together with an antihistamine or an antimuscarinic. 

Roughly one-third of people are highly susceptible to motion sickness, and most of the rest get motion sick under extreme conditions. 

The rates of space motion sickness have been estimated at between forty and eighty percent of those who enter weightless orbit. 

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