Motion sickness
From Wikipedia, the free encyclopedia
| Motion sickness Classification and external resources |
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| ICD-10 | T75.3 |
|---|---|
| ICD-9 | 994.6 |
| OMIM | 158280 |
| DiseasesDB | 11908 |
| MeSH | D009041 |
Motion sickness or kinetosis 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, carsickness, simulation sickness, airsickness, or space sickness.[1]
Dizziness, fatigue, and nausea are the most common symptoms of motion sickness.[2] Sopite syndrome is also a side effect of motion sickness. In fact, nausea in Greek means seasickness (naus means ship).[3][4] If the motion causing nausea is not resolved, the sufferer will frequently vomit. Unlike ordinary sickness, vomiting in motion sickness tends not to relieve the nausea.[1]
About 33% of people are susceptible to motion sickness even in mild circumstances such as being on a boat in calm water, although nearly 66% of people are susceptible in more severe conditions.[1][5] Approximately 50% of the astronauts in the U.S. space program have suffered from space sickness.[6] Individuals and animals without a functional vestibular system are immune to motion sickness.[7]
Motion sickness on the sea can result from being in the berth of a rolling boat without being able to see the horizon. Sudden jerky movements tend to be worse for provoking motion sickness than slower smooth ones, because they disrupt the fluid balance more.[1] A "corkscrewing" boat will upset more people than one that is gliding smoothly across the oncoming waves. Cars driving rapidly around winding roads or up and down a series of hills will upset more people than cars that are moving over smooth, straight roads. Looking down into one's lap to consult a map or attempting to read a book while a passenger in a car may also bring on motion sickness.
The most common hypothesis for the cause of motion sickness is that it functions as a defense mechanism against neurotoxins.[7] 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 disconcordance, the brain will come to the conclusion that one of them is hallucinating and further conclude that the hallucination is due to poison ingestion. The brain responds by inducing vomiting, to clear the supposed toxin.
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[edit] Kinds
[edit] Airsickness
Airsickness 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. Airsickness occurs when the central nervous system receives conflicting messages from the body (including the inner ear, eyes and muscles) affecting balance and equilibrium.
[edit] Sea-sickness
Seasickness 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 typically brought on by the rocking motion of the craft[8] or movement while immersed in water.[9]
[edit] Simulation sickness
Simulation sickness, or simulator sickness, is a condition where a person exhibits symptoms similar to motion sickness caused by playing computer/simulation/video games.[1]
The most common theory for the cause of simulation sickness is that the illusion of motion created by the virtual world, combined with the absence of motion detected by the inner ear, causes the area postrema in the brain to infer that one is hallucinating and further conclude that the hallucination is due to poison ingestion. The brain responds by inducing nausea and mass vomiting, to clear the supposed toxin.[7] According to this theory, simulation sickness is just another form of motion sickness.
The symptoms are often described as quite similar to that of motion sickness. Some can range from headache, drowsiness, nausea, dizziness, vomiting and sweating. A research done at the University of Minnesota had students play Halo for less than an hour, and found that up to 50 percent felt sick afterwards.[10]
In a study conducted by 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 1 hour, 44 (6%) reported that symptoms lasted longer than 4 hours, and 28 (4%) reported that symptoms lasted longer than 6 hours. There were also 4 (1%) reported cases of spontaneously occurring flashbacks".[11][12]
[edit] 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 all 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.
[edit] Treatment
Many cures and preventatives for motion sickness have been proposed.
[edit] Natural
One common suggestion is to simply look out of the window of the moving vehicle and to gaze toward the horizon in the direction of travel. This helps to re-orient the inner sense of balance by providing a visual reaffirmation of motion.[citation needed]
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).
Fresh, cool air can also relieve motion sickness slightly, although it is likely this is related to avoiding foul odors which can worsen nausea.
Especially while in a car, if you are the passenger and the vehicle is turning a lot on the road, it is best to stay in the front seat next to the driver and open the window, so that the wind coming from the opened window can make you fall asleep.[13]
Some people can cure it by pressing on a certain acupressure point on either wrist.[14] To find it, the person has to lay the other hand at a right angle to the wrist, with only the index, middle, and ring fingers on the arm. Whichever point is lying under the index finger is that certain acupressure point and by pressing down on it for about 5 minutes, a person can relieve their nausea. It's possible to have both hands pressing on both points.[15]
[edit] Chemical
Over-the-counter and prescription medications are readily available, such as Dramamine (dimenhydrinate)[16], Stugeron (cinnarizine) and Bonine/Antivert (meclizine).
Scopolamine is effective[17] and is sometimes used in the form of transdermal patches (1.5mg) or as a newer tablet form (0.4mg). 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 time treatment is required.
Interestingly, 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. The sedating anti-histamine medications such as promethazine, work quite well for motion sickness, although they can cause significant drowsiness.
Ginger root is a highly effective anti-emetic and sucking on crystallized ginger or sipping ginger tea can help to relieve the nausea.[18] A teaspoon of ground (powdered) ginger root has been proven to be as effective in preventing motion sickness as popular OTC chemicals, but without the drowsiness and sleepiness that is a common side reaction to dimenhydrinate or diphenhydrinate.
Soft drinks will also help to settle the stomach, and chewing gum or breath mints will help keep saliva from building up in the mouth.
[edit] Alternative
There are also alternative treatments for motion sickness that use acupressure points and electrical stimulation of the median nerve.
[edit] References
- ^ a b c d e f g h Benson AJ (2002). "35", Motion Sickness. In: Medical Aspects of Harsh Environments 2. Retrieved on 2008-05-09.
- ^ Motion Sickness Prevention and Treatment
- ^ Woodhouse's English-Greek Dictionary Page 745
- ^ Woodhouse's English-Greek Dictionary Page 766
- ^ PC Today Article - Motion Sickness
- ^ The Shorthorn Online | NEWS | Speech dispels space myths
- ^ a b c General Medical Officer (GMO) Manual: Clinical Section: Motion Sickness
- ^ Gahlinger PM (2000). "A comparison of motion sickness remedies in severe sea conditions". Wilderness Environ Med 11 (2): 136–7. PMID 10921365.
- ^ 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.
- ^ Could video games be making your kids sick?
- ^ CyberEdge Information Services: Health & Safety, Simulator Sickness in Virtual Environments: Executive Summary
- ^ Video Game Simulator Sickness
- ^ FAA Medical Certification / Alcohol / Substance / Drugs - Motion Sickness
- ^ Bertolucci LE, DiDario B (December 1995). "Efficacy of a portable acustimulation device in controlling seasickness". Aviat Space Environ Med 66 (12): 1155–8. PMID 8747609.
- ^ Iggulden, Conn, & Iggulden, Hal (2007). The Dangerous Book for Boys (U.S. Edition). HarperCollins Publishers, Inc., 10 East 53rd Street, New York, NY, 10022.
- ^ 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.
- ^ Spinks A, Wasiak J, Villanueva E, Bernath V (2007). "Scopolamine (hyoscine) for preventing and treating motion sickness". Cochrane database of systematic reviews (Online) (3): CD002851. doi:. PMID 17636710.
- ^ Ernst, E.; and M. H. Pittler (2000). "Efficacy of ginger for nausea and vomiting: a systematic review of randomized clinical trials" (PDF). British Journal of Anaesthesia 84 (3): 367–371.
[edit] External links
- Motion Sickness from MedlinePlus
- Motion Sickness Prevention and Treatment, from a Medical College of Wisconsin website
- Visually induced motion sickness research
- Golding JF., Motion Sickness Susceptibility Autonomic Neuroscience: Basic and Clinical 129 (2006) 67–76
- Rolnick, A., & Bles, W. (1989). Performance and well being under tilting conditions: the effects of visual reference and artificial horizon. Aviation, Space and Environmental Medicine, 60, 779-785
- Rolnick, A. & Gordon, C. R. (1991). The effects of motion induced sickness on military performance. In R. Gal & J. Mangelsdorff (Eds.), Handbook of Military Psychology. Chichester: Wiley.
- Rolnick, A., Lubow, R.E., 1991. Why is the driver rarely sick? The role of controllability in motion sickness. Ergonomics 34, 867–879.
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