Motion sickness is a condition in which there is a discord between visually perceptible movement and the movement of the vestibular system. Depending on the cause, it can also be referred to as seasickness, car drunkenness, simulated drunkenness or airsickness.
Dizziness, fatigue and nausea are the most common symptoms of motion sickness. Sopite syndrome, in which a person feels tired or exhausted, is also associated with motion sickness. "Nausea" in Greek means seasickness ( naus means ship). If movement causes nausea not resolved, the sufferer will usually vomit. Vomiting often will not relieve the feeling of weakness and nausea, which means the person may continue to vomit until the cause of nausea treated.
Video Motion sickness
Cause
The most common hypothesis for the cause of motion sickness is that it serves as a defense mechanism against neurotoxins. Postrema areas in the brain are responsible for inducing vomiting when toxins are detected, and to resolve conflicts between vision and balance. When feeling movement but not seeing it (for example, in a windowless vessel), the inner ear sends to the brain that feels movement, but the eye tells the brain that everything is still there. As a result of this imbalance, the brain will come to the conclusion that the individual is hallucinating and further concludes that hallucinations are due to the consumption of toxins. The brain responds by inducing vomiting, to clean up the suspected toxin. The indirect argument Treisman has recently been questioned through alternative direct evolutionary hypotheses, as well as modified and expanded through the direct toxic hypothesis. The direct evolutionary hypothesis basically states that there is a reasonable means in which real or real movements can contribute directly to the evolution of hostile reactions, without the need to co-opt the toxic response as proposed by Treisman. Nevertheless, the direct toxic hypothesis holds that there is still a plausible way in which the body's toxic response system may have played a role in shaping the evolution of some signature symptoms that characterize motion sickness.
An alternative theory, also known as the Nystagmus Hypothesis, has been proposed based on vagal nerve stimulation resulting from extra-ocular muscle stretching or traction [1] occurring in conjunction with eye movements caused by vestibular stimulation. There are three important aspects to this theory: first is the close relationship between activity in the vestibular system, that is, the semicircular canal and otolith organ, and the change of tone between the various eyes of the six extra-ocular muscles of the eye. Thus, with the exception of voluntary eye movements, the vestibular and oculomotor systems are completely linked. Second is the Sherrington Law operation that describes the reciprocal inhibition between the agonist antagonist muscle pair, and with the extraocular stretching implications that must occur whenever Sherrington's Law is made to fail, causing the noncontracting muscle (to be stretched). Finally there is a critical presence of afferent output to the Vagus nerve as a direct result of stretching of the eye muscles or traction. Thus, nerve stimulation resulting from eye muscle stretching is proposed as the cause of motion sickness. This theory explains why individuals with labyrinth defects are immune to motion sickness; why symptoms occur when undergoing multiple head-body accidents; why a combination of voluntary and reflexive eye movements can challenge the proper operation of Sherrington's Law, and why many drugs that suppress eye movements also serve to suppress symptoms of movement symptoms.
A recent theory argues that the main reason for motion sickness is due to an imbalance in vestibular output that supports semicircular (nauseogenic) channels vs. otolith organs (anti-nauseogenic). This theory tries to integrate previous theories about motion sickness. For example, there are many sensory conflicts related to motion sickness and many do not, but those where channel stimulation occurs in the absence of normal otolith functions (eg, 0 -g) are the ones most provocative. The theory of vestibular imbalance is also related to the different roles of otoliths and canals in autonomous passion (otolith output is more sympathetic).
Vulnerability
About a third of the population is highly susceptible to motion sickness and most of the rest may experience motion sickness in extreme conditions. Several factors affect the susceptibility to motion sickness. Statistics show that women are more likely to be affected than men and that risk decreases with age. There is some evidence that people with Asian ancestors experience travel sickness more often than those of European descent, and there are situational and behavioral factors, such as whether passengers have views about the way ahead, and eating patterns and eating behaviors.
Maps Motion sickness
Type
Motion sickness can be divided into three categories:
- Motion sickness caused by a perceived but invisible movement
- Motion motion caused by visible but not noticeable movement
- Motion pain occurs when both systems detect motion but are not appropriate.
Motion is felt but not visible
In this case, the movement is perceived by the vestibular system and hence the movement is felt, but no motion or slight movement is detected by the visual system.
car sickness
The specific form of motion sickness, car diseases, is quite common and is proven by intolerance to read maps or books during the journey. Car disease results from sensory conflicts that arise in the brain from different sensory inputs. Motion sickness is caused by a conflict between the signals coming in the brain from the inner ear, which forms the basis of the vestibular system, the sensory device associated with motion and balance, and which detects motion mechanically. If someone sees stationary objects in a vehicle, like a magazine, their eyes will tell their brains that what they see does not move. Their inner ear, however, would contradict this by sensing the movement of the vehicle. Different theories are there that cause. One suggests a motion gaze while driving a moving vehicle while other body sensors feel the silence, creating a conflict between the eyes and inner ear. Others suggest the eyes mostly see the inside of the car that is not moving while the vestibular system of the inner ear feels movement when the vehicle runs in a corner or on a hill and even a small mound. Therefore, the effect is worse when looking down but can be reduced by looking outside the vehicle.
At the beginning of the 20th century, Austrian-Hungarian scientist Robert Barany observed the movement back and forth from the eyes of the train passengers as they looked out the side windows in whipping scenes. He called it the "nystagmus train." Also called "optokinetic nystagmus." This causes nausea and vomiting. His findings are published in the journal Laeger, 83: 1516, Nov.17, 1921.
air drunken
Air disease is a sensation caused by air travel. This is a specific form of motion sickness and is considered a normal response to healthy individuals. This is basically the same as car sickness but occurs in airplanes. An aircraft can accumulate and tilt sharply, and unless the passenger is in a window seat, they may only see the inside of the aircraft due to the small window size. Another factor is that when in flight, the view outside the window can be blocked by the cloud, preventing passengers in the window seeing the ground move or move a lower cloud.
Sea disease
Marine disease is a form of motion sickness characterized by a feeling of nausea and, in extreme cases, the vertigo experienced after spending time in a craft on water. Basically the same as car diseases, although the movement of water boats tend to be more orderly. This is usually caused by a rocking motion of the plane or movement when immersed in water. As with air drunkenness, it can be difficult to visually detect motion even if one sees outside the boat because water does not offer fixed points for visually assessing motion. Poor visibility conditions, such as fog, can worsen sea diseases. Some people with car diseases are resistant to marine diseases and vice versa.
Centrifugal
Rotating devices such as centrifuges used in astronaut training and amusement park rides like Rotor, Mission: Space and Gravitron can cause vehicle drunks in many people. While the inside of the centrifuge does not seem to move, a person will feel the movement. In addition, the centrifugal force can cause the vestibular system to give one downward sense of being in the direction far from the centrifuge center rather than the right downward direction.
Dizziness as it spins
When a person spins and stops abruptly, the fluid in the inner ear keeps turning causing a sense of continuous spin while one's visual system no longer detects movement.
Virtual reality
Usually the VR program will detect the user's head movement and interfere with vision rotation to avoid dizziness. However, some cases such as lagging systems or software hacking may cause the vision to freeze. In such cases, even some small head movements can trigger the disease.
Visible but not present motion
In this case, the motion is detected by the visual system and hence its movement is visible, but no motion or small movement is perceived by the vestibular system. Drunk diseases arising from such situations have been referred to as "motion sickness induced visually" (VIMS).
More movies and videos
This type of disease is very common when people are susceptible to watching movies on big screens such as IMAX, but may also occur in regular movie theaters or even when watching TV. For the sake of novelty, IMAX and other types of panoramic theater often show dramatic movements such as flying over a landscape or climbing a roller coaster. This type of motion sickness can be prevented by closing one's eyes during the scene.
In the regular format theater, the example of a movie that causes drunkenness in many people is The Blair Witch Project . Cinema warns customers about the possible effects of nausea, especially in pregnant women. Blair Witch was filmed with a handheld camcorder, which experienced more movement than the average film camera, and lacked a steadicams stabilization mechanism.
Home movies, often filmed with handheld cameras, also tend to cause motion sickness to those who see them. Camera-people rarely notice this during filming because their sense of movement matches the movement seen through the camera viewfinder. Those who see the movie afterwards see only movement, which may be quite large, without a sense of movement. Using the zoom function seems to contribute to motion sickness as well, since zoom is not a normal function of the eye. The use of a tripod or camcorder with image stabilization technology during filming can minimize this effect.
Virtual reality
Motion sickness due to virtual reality is very similar to the simulation of sickness and motion sickness due to film. In virtual reality, however, the effect is made more acute since all external reference points are blocked from the vision, the simulated image is three dimensional and in some cases stereo sound can also give a sense of movement. NADS-1, a simulator located at the National Advanced Driving Simulator, is able to accurately stimulate the vestibular system with a 360-degree horizontal viewing field and a 13-degree freedom base. Studies have shown that exposure to rotational motion in a virtual environment can lead to a significant increase in nausea and other symptoms of motion sickness.
In a study conducted by the US Army Research Institute for Behavioral and Social Sciences in a report published in May 1995 titled "Technical Report 1027 - Simulator Disease in a Virtual Environment", of 742 pilot exposures of 11 military flight simulators, "roughly half of pilot (334) reported post-effects of several types: 250 (34%) reported that symptoms disappeared in less than one hour, 44 (6%) reported that symptoms lasted more than four hours, and 28 (4%) reported that symptoms persisted for more than six hours There were also four (1%) cases of spontaneous flashbacks reported. "
Space ailment
The aerospace disease is effectively unknown during the earliest space flight, as this is done in very narrow conditions; apparently compounded by being able to move freely, and more commonly in larger spacecraft. About 60% of Space Shuttle astronauts currently experience it on their first flight; the first case is now suspected as Gherman Titov, in August 1961 on board Vostok 2 , which reported dizziness and nausea. However, the first important cases occurred on early Apollo flights; Frank Borman at Apollo 8 and Rusty Schweickart at Apollo 9 . Both experience symptoms that can be identified and quite severe - in the latter case causing the mission plan to be modified.
Movement seen and felt but not appropriate
When moving within a rotating frame of reference such as in a centrifuge or environment in which gravity is simulated by centrifugal force, the coriolis effect causes a sense of movement in the vestibular system that is incompatible with visible motion.
Sometimes when driving a vehicle for a long time on an unmanaged road very slowly (10-20 km/h) the speed of both senses fails to adjust. Due to poor road quality, the vehicle will be too jolted to give a sense of heavy movement to the inner ear, but because of the slow speed, the eye does not feel the amount of motion is proportional.
Treatment
Many drugs and prevention for motion sickness have been proposed.
Device
Eye-protection device blocking patented movement (US Pat. No. 6,275,998) to prevent car motion sickness. Visual cues are important contributors to onshore vehicle travel alongside vestibular input (inner ear). The eyepiece limits what the wearer sees outside the moving vehicle using an opaque shield. By removing visual queses outside the vehicle, the device normalizes the dimensions of visual input involved in sensory conflicts, a leading theory behind motion sickness. There is no evidence that motion blocking glasses alter or eliminate other vestibular or body receptor inputs. Car illness is the most common type of motion sickness considering the number of travelers traveling acrossland rather than those traveling by air or by sea.
A computer device that is worn on the head with a transparent screen can be used to reduce the effects of motion sickness (and spatial disorientation) if the visual indicator of the user head position is displayed. Such devices work by providing users with a digital reference line in their field of vision that indicates the horizon position relative to the user's head. This is done by combining readings from accelerometers and gyroscopes installed in the device (US Pat. No. 5,966,680). This technology has been applied in both stand-alone devices and Google Glass. In two NIH-supported studies, more than 90% of patients experienced a reduction in hangover symptoms while using this technology.
Activity
One general suggestion is to just look out of the moving vehicle window and gaze at the horizon toward the journey. It helps to reorient the inner balance by giving visual reinforcement of motion.
At night, or on a windowless boat, it would be helpful to close your eyes, or if possible, take a nap. This resolves the input conflicts between the eyes and the inner ear. Napping also helps prevent psychogenic effects (ie the effect of the disease being magnified by thinking of it).
Fresh and cool air can also relieve a hangover, though this may be linked to avoiding foul odors that can aggravate nausea.
When playing computer games, and especially in first-person shooter games, some simulation cases can be solved by changing the field of view in the game. Some games have default settings that place the player's vision at a small distance in front of the actual controlled object, which will most likely trigger a disease simulation.
Medication
Over-the-counter and prescribed medicines are available, such as dimenhidrinate, scopolamine, meclizine, promethazine, cyclizine, and cinnarizine. Cinnarizine is not available in the United States, as it is not FDA approved. Because these drugs often have side effects, anyone involved in high-risk activities while at sea (such as SCUBA divers) should evaluate the risks versus their benefits. Promethazine is especially known to cause drowsiness, which is often opposed by ephedrine in a combination known as the "Coast Guard Cocktail." There are special considerations to be taken of when anti-movement drugs are commonly used in military settings where performance must be maintained at a high level.
Scopolamine is effective and is sometimes used in the form of transdermal patch (1.5 mg) or as a newer tablet form (0.4 mg). Selection of transdermal patch or scopolamine tablets is determined by the physician after considering the patient's age, weight, and length of treatment required.
Many effective pharmacological treatments 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 not effective for the prevention and treatment of motion sickness. This is due to the CNS vomiting center physiology and its input from the trigger zone of chemoreceptor versus inner ear. Sedation of anti-histamine drugs such as promethazine works well enough for motion sickness, although they can cause significant drowsiness.
Ginger root is generally regarded as an effective anti-emetic, but is not effective in treating drunk.
Electronics
When astronauts often experience motion sickness, NASA has conducted extensive research on the causes and treatments for motion sickness. One of the most promising looking treatments is for people suffering from hangovers to wear LCD shutter sunglasses that creates 4Hz stroboscopic sight with a distance of 10 milliseconds.
References
External links
- Media related to Movement diseases in Wikimedia Commons
- Davis, Christopher J.; Lake-Bakaar, Gerry V.; Grahame-Smith, David G. (December 6, 2012). Nausea and Vomiting: Mechanism and Treatment . Springer Science & amp; Business Media. p.Ã, 123. ISBNÃ, 978-3-642-70479-6.
- Motion Sickness from MedlinePlus
- Visual motion motion sickness research
- Motion Sickness Education Video
Source of the article : Wikipedia
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