Motion sickness

For the album by Bright Eyes, see Motion Sickness.
Motion sickness
Classification and external resources
Specialty neurology
ICD-10 T75.3
ICD-9-CM 994.6
OMIM 158280
DiseasesDB 11908
eMedicine article/2060606
MeSH D009041

Motion sickness, also known as kinetosis and travel sickness, is a condition in which a disagreement exists between visually perceived movement and the vestibular system's sense of movement. Depending on the cause, it can also be referred to as seasickness, car sickness, simulation sickness or airsickness.[1]

Dizziness, fatigue, and nausea are the most common symptoms of motion sickness.[2] Sopite syndrome, in which a person feels fatigue or tiredness, is also associated with motion sickness. "Nausea" in Greek means seasickness (naus means ship).[3][4] If the motion causing nausea is not resolved, the sufferer will usually vomit. Vomiting often will not relieve the feeling of weakness and nausea, which means the person might continue to vomit until the cause of the nausea is treated.

Cause

The most common hypothesis for the cause of motion sickness is that it functions as a defense mechanism against neurotoxins.[5] The area postrema in the brain is responsible for inducing vomiting when poisons are detected, and for resolving conflicts between vision and balance. When feeling motion but not seeing it (for example, in a ship with no windows), the inner ear transmits to the brain that it senses motion, but the eyes tell the brain that everything is still. As a result of the discordance, the brain will come to the conclusion that the individual is hallucinating and further conclude that the hallucination is due to poison ingestion. The brain responds by inducing vomiting, to clear the supposed toxin. Treisman's indirect argument has recently been questioned via an alternative direct evolutionary hypothesis, as well as modified and extended via a direct poison hypothesis.[6] The direct evolutionary hypothesis essentially argues that there are plausible means by which ancient real or apparent motion could have contributed directly to the evolution of aversive reactions, without the need for the co-opting of a poison response as posited by Treisman. Nevertheless, the direct poison hypothesis argues that there still are plausible ways in which the body's poison response system may have played a role in shaping the evolution of some of the signature symptoms that characterize motion sickness.

An alternative theory, also known as the Nystagmus Hypothesis,[7] has been proposed based on stimulation of the Vagus nerves resulting from the stretching or traction of extra-ocular muscles co-occurring with eye movements caused by vestibular stimulation. There are three critical aspects to the theory: first is the close linkage between activity in the vestibular system, i.e., semicircular canals and otolith organs, and a change in tonus among various of each eye's six extraocular muscles. Thus, with the exception of voluntary eye movements, the vestibular and oculomotor systems are thoroughly linked.

Second is the operation of Sherrington's Law[8] describing reciprocal inhibition between agonist-antagonist muscle pairs, and by implication the stretching of extraocular muscle that must occur whenever Sherrington's Law is made to fail, thereby causing an unrelaxed (contracted) muscle to be stretched.

Finally is the critical presence of afferent output to the Vagus nerves as a direct result of eye muscle stretch or traction.[9] Thus, 10th nerve stimulation resulting from eye muscle stretch is proposed as the cause of motion sickness.

The theory explains why labyrinthine defective individuals are immune to motion sickness;[10][11] why symptoms emerge when undergoing various body-head accelerations; why combinations of voluntary and reflexive eye movements may challenge the proper operation of Sherrington's Law; and why many drugs that suppress eye movements also serve to suppress motion sickness symptoms.[12]

Types

Motion sickness can be divided into three categories:

  1. Motion sickness caused by motion that is felt but not seen
  2. Motion sickness caused by motion that is seen but not felt
  3. Motion sickness caused when both systems detect motion but they do not correspond.

Motion is felt but not seen

In these cases, motion is sensed by the vestibular system and hence the motion is felt, but no motion or little motion is detected by the visual system.

Car sickness

A specific form of motion sickness, car sickness is quite common and often evidenced by the inability to read a map or book during travel. Car sickness results from the sensory conflict arising in the brain from differing sensory inputs. Varying theories exist as to cause. One suggests the eyes view motion while riding in the moving vehicle while other body sensors sense stillness, creating conflict between the eyes and inner ear. Another suggests the eyes mostly see the interior of the car which is motionless while the vestibular system of the inner ear senses motion as the vehicle goes around corners or over hills and even small bumps. Therefore, the effect is worse when looking down but may be lessened by looking outside of the vehicle.

In the early 20th century, Austro-Hungarian scientist Robert Barany observed the back and forth movement of the eyes of railroad passengers as they looked out the side windows at the scenery whipping by. He called it "railway nystagmus." Also called "optokinetic nystagmus." It causes nausea and vomiting. His findings were published in the journal Laeger, 83:1516, Nov.17, 1921.

Air sickness

Main article: Airsickness

Air sickness is a sensation which is induced by air travel.[1] It is a specific form of motion sickness and is considered a normal response in healthy individuals. It is essentially the same as car sickness but occurs in an aeroplane. However, some significant differences are that an aeroplane may bank and tilt sharply and due to the small window sizes, unless the passenger is at a window seat he is likely to see only the stationary interior of the plane. Another factor is that while in flight, the view out of windows may be blocked by clouds, preventing a passenger at the window from seeing the moving ground or moving lower clouds.

Sea sickness

Main article: Seasickness

Sea sickness is a form of motion sickness characterized by a feeling of nausea and, in extreme cases, vertigo experienced after spending time on a craft on water.[1] It is essentially the same as car sickness, though the motion of a watercraft tends to be more constant. It is typically brought on by the rocking motion of the craft[13] or movement while immersed in water.[14] As with air sickness, it can be difficult to visually detect motion even if one looks outside of the boat as water does not offer fixed points with which to visually judge motion. Poor visibility conditions, such as fog, may worsen sea sickness. Some sufferers of car sickness are resistant to sea sickness and vice versa.

Centrifuges

Rotating devices such as centrifuges used in astronaut training and amusement park rides such as the Rotor, Mission: Space and the Gravitron can cause motion sickness in many people. While the interior of the centrifuge does not appear to move, one will experience a sense of movement. In addition, centrifugal force can cause the vestibular system to give one the sense that downward is in the direction away from the center of the centrifuge rather than the true downward direction.

Dizziness due to spinning

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 that is seen but not felt

In these cases, motion is detected by the visual system and hence the motion is seen, but no motion or little motion is sensed by the vestibular system. Motion sickness arising from such situations has been referred to as "visually induced motion sickness" (VIMS).[15]

Films and other video

This type of sickness is particularly prevalent when susceptible people are watching films on large screens such as IMAX, but may also occur in regular format theaters or even when watching TV. For the sake of novelty, IMAX and other panoramic type theaters often show dramatic motions such as flying over a landscape or riding a roller coaster. This type of motion sickness can be prevented by closing one's eyes during such scenes.

Due to experience motion sickness can be induced much more faster. A pilot can get motion sick from watching a cockpit video, while a random person at the same video wouldn't. The same goes for rally car drivers watching rally car videos, etc.

In regular format theaters, an example of a movie that caused motion sickness in many people is The Blair Witch Project. Theaters warned patrons of its possible nauseating effects, cautioning pregnant women in particular. Blair Witch was filmed with a handheld camcorder, which was subjected to considerably more motion than the average movie camera.

Home movies, often filmed with a hand-held camera, also tend to cause motion sickness in those that view them. The camera-person rarely notices this during filming since their sense of motion matches the motion seen through the camera's viewfinder. Those who view the film afterward only see the movement, which may be considerable, without any sense of movement. Using the zoom function seems to contribute to motion sickness as well, as zooming is not a normal function of the eye. The use of a tripod or a camcorder with image stabilization technology while filming can minimize this effect.

Virtual reality

Motion sickness due to virtual reality is very similar to simulation sickness and motion sickness due to films. In virtual reality, however, the effect is made more acute as all external reference points are blocked from vision, the simulated images are three-dimensional and in some cases stereo sound that may also give a sense of motion. The NADS-1, a simulator located at the National Advanced Driving Simulator, is capable of accurately stimulating the vestibular system with a 360-degree horizontal field of view and 13 degrees of freedom motion base.[16] Studies have shown that exposure to rotational motions in a virtual environment can cause significant increases in nausea and other symptoms of motion sickness.[17]

In a study conducted by the U.S. Army Research Institute for the Behavioral and Social Sciences in a report published May 1995 titled "Technical Report 1027 - Simulator Sickness in Virtual Environments", out of 742 pilot exposures from 11 military flight simulators, "approximately half of the pilots (334) reported post-effects of some kind: 250 (34%) reported that symptoms dissipated in less than one hour, 44 (6%) reported that symptoms lasted longer than four hours, and 28 (4%) reported that symptoms lasted longer than six hours. There were also four (1%) reported cases of spontaneously occurring flashbacks."[18]

Space sickness

Space sickness was effectively unknown during the earliest spaceflights, as these were undertaken in very cramped conditions; it seems to be aggravated by being able to freely move around, and so is more common in larger spacecraft.[1] Around 60% of Space Shuttle astronauts currently experience it on their first flight; the first case is now suspected to be Gherman Titov, in August 1961 onboard Vostok 2, who reported dizziness and nausea. However, the first significant cases were in early Apollo flights; Frank Borman on Apollo 8 and Rusty Schweickart on Apollo 9. Both experienced identifiable and reasonably severe symptoms—in the latter case causing the mission plan to be modified.

Motions that are seen and felt but do not correspond

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

Sometimes when riding a vehicle for a long time on a badly maintained road at a very slow (10–20 km/h) speed the two senses fail to correspond. Due to the poor road quality the vehicle will jerk too much giving a sense of severe motion to the inner ear, but due to the slow speed, the eye doesn't sense a proportional amount of motion.

Treatment

Many cures and preventatives for motion sickness have been proposed.

Devices

A head-worn, computer device with a transparent display can be used to mitigate the effects of motion sickness (and spatial disorientation) if visual indicators of the wearer’s head position are shown.[19] Such a device functions by providing the wearer with digital reference lines in their field of vision that indicate the horizon’s position relative to the user’s head. This is accomplished by combining readings from accelerometers and gyroscopes mounted in the device (US Patent 5,966,680).[20] This technology has been implemented in both standalone devices[21] and Google Glass.[22][23] In two NIH-backed studies, greater than 90% of patients experienced a reduction in the symptoms of motion sickness while using this technology.[19]

Activity

One common suggestion is to simply look out of the window of the moving vehicle and to gaze towards the horizon in the direction of travel. This helps to re-orient the inner sense of balance by providing a visual reaffirmation of motion.

In the night, or in a ship without windows, it is helpful to simply close one's eyes, or if possible, take a nap. This resolves the input conflict between the eyes and the inner ear. Napping also helps prevent psychogenic effects (i.e. the effect of sickness being magnified by thinking about it).

A simple method for relieving common and mild car sickness is chewing. Chewing gum has an uncanny effectiveness for reducing car sickness in those affected. Chewing gum, however, is not the only thing one may chew to relieve mild effects of car sickness, snacking on sweets or just chewing in general seems to reduce adverse effects of the conflict between vision and balance.

Fresh, cool air can also relieve motion sickness slightly, although it is likely this is related to avoiding foul odors which can worsen nausea.[24]

While playing computer games, and mainly in first-person shooter games, some cases of simulation sickness can be resolved by changing the field of view in the game. Some games have a default setting which places a player's vision a small distance ahead of the actual object controlled, which will most likely trigger simulation sickness.

Medication

Over-the-counter and prescription medications are readily available, such as Dramamine (dimenhydrinate),[25] Stugeron (cinnarizine), and Bonine/Antivert (meclizine). Cinnarizine is not available in the United States, as it is not approved by the FDA.

Scopolamine is effective[26] and is sometimes used in the form of transdermal patches (1.5 mg) or as a newer tablet form (0.4 mg). The selection of a transdermal patch or scopolamine tablet is determined by a doctor after consideration of the patient's age, weight, and length of treatment time required.

Many pharmacological treatments which are effective for nausea and vomiting in some medical conditions may not be effective for motion sickness. For example, metoclopramide and prochlorperazine, although widely used for nausea, are ineffective for motion-sickness prevention and treatment. This is due to the physiology of the CNS vomiting centre and its inputs from the chemoreceptor trigger zone versus the inner ear. Sedating anti-histamine medications such as promethazine work quite well for motion sickness, although they can cause significant drowsiness.[27]

Ginger root is commonly thought to be an effective anti-emetic, but it is ineffective in treating motion sickness.[28]

Ginger is as effective as dimenhydrinate in the treatment of nausea and vomiting during pregnancy and has fewer side effects.[29]

Electronic

As astronauts frequently have motion sickness, NASA has done extensive research on the causes and treatments for motion sickness. One very promising looking treatment is for the person suffering from motion sickness to wear LCD shutter glasses that create a stroboscopic vision of 4 Hz with a dwell of 10 milliseconds.[30]

References

  1. 1 2 3 4 Benson, AJ (2002). "35" (PDF). Motion Sickness. In: Medical Aspects of Harsh Environments. 2. Washington, DC. Retrieved 2008-05-09.
  2. ↑ Motion Sickness Prevention and Treatment
  3. ↑ Woodhouse's English-Greek Dictionary Page 745
  4. ↑ Woodhouse's English-Greek Dictionary Page 766
  5. ↑ Motion sickness: an evolutionary hypothesis
  6. ↑ Lawson, B. D. (2014). Motion sickness symptomatology and origins. Handbook of Virtual Environments: Design, Implementation, and Applications, 531-599.
  7. ↑ Ebenholtz,S.M., Cohen,M.M.,& Linder,B.J. The Possible Role of Nystagmus in Motion Sickness:a Hypothesis. Aviation, Space, and Environmental Medicine,1994,65,1032-1035
  8. ↑ Sherrington, C.S. Further experimental note on the correlation of action of antagonistic muscles. Proceedings of the Royal Society,B53,1893,407-420.
  9. ↑ Milot,L.A.,Jacob,J.L.,Blanc,V.F.,Hardy,J.F. The Oculocardiac reflex in strabismus surgery. Canadian Journal of Ophthalmology, 1983, 18, 314-317
  10. ↑ Kennedy,R.S.,Graybiel,A.,McDonough,R.C.,Beckwith,F.D. Symptomatology under storm conditions in the North Atlantic in control subjects and in persons with bilateral labyrinthine defects. Acta Otolaryngology, 1968, 66, 533-540.
  11. ↑ Cheung, B.S., Howard I.P.,Money, K.E. Visually-induced sickness in normal and bilaterally labyrinthine-defective subjects. Aviation, Space, and Environmental Medicine, 1991,62, 527-531.
  12. ↑ Ebenholtz,S.M.Oculomotor Systems and Perception. Cambridge University Press, 2005,148-153
  13. ↑ Gahlinger PM (2000). "A comparison of motion sickness remedies in severe sea conditions". Wilderness Environ Med. 11 (2): 136–7. doi:10.1580/1080-6032(2000)011[0136:LTTE]2.3.CO;2. PMID 10921365.
  14. ↑ Norfleet WT, Peterson RE, Hamilton RW, Olstad CS (January 1992). "Susceptibility of divers in open water to motion sickness". Undersea Biomed Res. 19 (1): 41–7. PMID 1536062. Retrieved 2008-05-09.
  15. ↑ So, R.H.Y. and Ujike, H. (2010) Visually induced motion sickness, visual stress and photosensitive epileptic seizures: what do they have in common? - Preface to the special issue. Applied Ergonomics, 41(4), pp.491-393.
  16. ↑ "The National Advanced Driving Simulator - The NADS-1". Nads-sc.uiowa.edu. Retrieved 2014-03-02.
  17. ↑ So, R.H.Y. and Lo, W.T. (1999) "Cybersickness: An Experimental Study to Isolate the Effects of Rotational Scene Oscillations." Proceedings of IEEE Virtual Reality '99 Conference, March 13–17, 1999, Houston, Texas. Published by IEEE Computer Society, pp. 237–241.
  18. ↑ CyberEdge Information Services: Health & Safety, Simulator Sickness in Virtual Environments: Executive Summary
  19. 1 2 Krueger, WW (Jan 2011). "Controlling motion sickness and spatial disorientation and enhancing vestibular rehabilitation with a user-worn see-through display.". Laryngoscope. 121 (Suppl 2.): 17–35. doi:10.1002/lary.21373. PMID 21181963. Retrieved 15 July 2014.
  20. ↑ "USPTO #5,966,680". USPTO.gov. United States Patent and Trademark Office. Retrieved 15 July 2014.
  21. ↑ "Air Force to examine AdviTech's motion-sickness product for combat pilots". San Antonio Business Journal. Nov 10, 2010. Retrieved 15 July 2014.
  22. ↑ "BCMC, LLC". Retrieved 15 July 2014.
  23. ↑ "Google Glass Treating Motion Sickness". YouTube.com. Retrieved 15 July 2014.
  24. ↑ FAA Medical Certification / Alcohol / Substance / Drugs - Motion Sickness
  25. ↑ Weinstein SE, Stern RM (October 1997). "Comparison of marezine and dramamine in preventing symptoms of motion sickness". Aviat Space Environ Med. 68 (10): 890–4. PMID 9327113.
  26. ↑ Spinks AB, Wasiak J, Villanueva EV, Bernath V (2007). Wasiak J, ed. "Scopolamine (hyoscine) for preventing and treating motion sickness". Cochrane database of systematic reviews (Online) (3): CD002851. doi:10.1002/14651858.CD002851.pub3. PMID 17636710.
  27. ↑ Li–gui, Huang; En–tong, Wang; Wei, Chen; Wei–xi, Gong (June 2011). "Role of Histamine H1 Receptors in Vestibular Nucleus in Motion Sickness". Journal of Otology. 6 (1): 20–25. doi:10.1016/S1672-2930(11)50003-0.
  28. ↑ Brainard A, Gresham C (2014). "Prevention and treatment of motion sickness". Am Fam Physician. 90 (1): 41–6. PMID 25077501.
  29. ↑ Pongrojpaw D, Somprasit C, Chanthasenanont A (2007). "A randomized comparison of ginger and dimenhydrinate in the treatment of nausea and vomiting in pregnancy.". Journal of the Medical Association of Thailand. 90: 1703–9. PMID 17957907.
  30. ↑ Stroboscopic Vision as a Treatment for Space Motion Sickness

Do Visual Background Manipulations Reduce Simulator Sickness? In Proceedings of International Workshop on Motion Sickness / academic papers on a solution at http://www.hitl.washington.edu/projects/common/papers.php?idx=23

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