Motion Sickness: Review of Different Countermeasures Research Paper

Abstract

Motion sickness is a condition that commonly affects travelers. Many theories have been put in place to explain its pathogenesis. Many treatments have been tried, with pharmacotherapy being widely applied. This paper looks at the different available countermeasures. The paper is an article review that analyzes the findings of literature that has been done on some of the motion sickness countermeasures.

The countermeasures are mainly the use of stroboscopic light, the use of habituation and adaptation training, and the traditional use of acupuncture and acustimulation. Pharmacotherapy is mainly the use of scopolamine. This drug, along with other drugs, has severe side effects. The most effective countermeasures are the pharmacological interventions. Scopolamine transdermal patch is effective with reduced side effects. Non-pharmacologic measures are less effective.

Motion Sickness: Detailed Review of Different Countermeasures

Motion sickness is a common condition in travelers. It is a common cause of distress in many people. Lackner (4) describes it as the normal universal physiological response to unusual perception of motion, whether real or apparent. The condition has significant effects on the travelling activities. It is currently the focus of many research articles and publications. The cause of the condition has been widely studied, with the available evidence pointing to the role of otoliths in its pathogenesis.

Traditionally, the sensory inconsistency hypothesis was important in the causation of motion disease. However, new research has led to the formulation of more theories. One of the theorists suggests an association between the condition and genetic polymorphism that is observed in the alpha 2 adrenergic receptors, with these sensory systems causing heightened response to motion sickness and stress (4).

There exist a number of physiological measures in the prediction and evaluation of the condition, but none of these has been associated with high sensitivity or specificity (4). The treatment and prevention of the condition is diverse, with pharmacological and non-pharmacological measures being applied.

The pharmacological therapies have been widely applied. Research is currently ongoing to test some of the promising medication methods. According to Lackner (4), non-pharmacological measures are mainly based on the reduction of conflicting sensory inputs, accelerating the multi-sensory adaptation process, and the promotion of psychological factors that are recognized as favoring sensory adaptation.

Centrally acting anticholinergic drugs and the H1 antihistamines are some of the most effective drugs treating motion sickness, with the only limiting factor being the adverse effects. Pilots, drivers, and other people who are engaged in such activities are not commonly advised to use these drugs as their side effect profile can affect their work output. Seasickness has been described as the most dramatic form of motion sickness.

It ranks ahead of other forms of motion sickness such as train sickness, carsickness, and airsickness (4). A fifth form of motion sickness, space sickness, has also been described as common in astronauts who work in environments without gravity or with microgravity. With the advent of simulation technology, it is now easier to study motion sickness.

The results of the simulation show that it develops in an order, with some symptoms being felt before the major symptoms. These symptoms include the abdominal discomfort, followed by nausea and malaise. Peri-oral pallor may also follow, although accompanied by facial pallor, cold sweating, and worsening of the initial symptoms (4).

Other symptoms include salivation, bad flushing, drowsiness, fatigue and retching. They can last for hours after the episode of sickness. Prolonged exposure to the responsible stimulus, increased intensity of the stimulus, or the increased susceptibility may cause depression behavior change and apathy in the patient.

These symptoms, accompanied by decrease psychomotor and cognitive performance, constitute the Sopite syndrome (4). The study of motion sickness, the treatment, and diagnosis modalities, as well as the prevention strategies is an important topic for research. This article is a detailed review of the literature on motion sickness. It attempts to review the different countermeasures.

Literature Review

As earlier stated, there are numerous literatures on motion sickness, with most of these sources mainly focusing on the management and pathophysiology. This section reviews some of the literature materials on the topic.

Etiology and Pathogenesis

The etiology of motion sickness has been the focus of many literatures, but there is no generally accepted explanation. Lackner (4) states that the “sensory conflict” theory suggested by Reason and Brand is the closest that researcher have come in the attempt to explain the condition. In this theory, motion sickness is supposedly caused by an inharmonious interpretation of movement by the brain triggering the response (4). The stimuli cause delivery of messages to the brain through the special sensory parts in the body, with examples being the eyes, proprioceptors, and the vestibular receptors in the ear (4).

The signals from the sensory systems often conflict with the other senses, with the result of this case being the sickness. The sensory conflict theory is insufficient in explanation of motion sickness produced by some of the conditions. The theory that is increasingly being suggested in causation of motion sickness is postural instability theory.

According to Lackner, this theory was developed from the observations in experiments that the motion sickness was preceded by increased postural sway in individuals, with this observation being statistically significant (4). The theory suggests that the body is lacking in the control of postural motion, and hence the adverse response in motion sickness (4).

Motion simulators have provided a large body of knowledge on the causation of motion sickness. Hippocrates described seasickness as being directly caused by the motion patterns of a travelling vessel. Repetitive linear and angular head acceleration has been credited with the causation of motion sickness. Research by Lackner (4) indicates that the vertical linear acceleration in ships is an important etiology. Motion is not just considered a case of motion sickness. However, specific motions are attributed to the sickness.

The motions of rolling and pitching have not been found significant causes of motion sickness. Nevertheless, the combination of these motions with heave resulted in motion sickness (4). Lackner (4) suggested that the horizontal translational oscillations in the surge and sway directions are statistically significant on the causation of motion sickness.

The researchers also stated that repeated exposure to a stimulus that is responsible for the motion sickness causes attenuation, and in some cases complete disappearance of the symptoms of the condition. The duration of time after which these changes take effect is different in different individuals, with most of the changes taking place within days.

Another outcome that is described is habituation. According to Lackner (4), this outcome is a learned central process. In habituation, the decreased susceptibility to the stimulus is a cause of motion sickness, which occurs if there is an interval between the stimuli. Some researchers suggested that motion sickness occurs because of the vestibular nuclear mediated eye movements.

Lackner (4) asserts that the motion-induced nystagmic responses lead to considerable traction of the extraocular muscles with activation of the oculocardiac reflex and vagusnerve stimulation. The trigeminal nerve through some of its fibers can also be responsible for the motion sickness. The effect of the nerve in relation to the motion sickness is the migraines that accompany the condition.

Another theory in the explanation of motion sickness etiology is the subjective vertical conflict theory. In this theory, the researchers associated the motion sickness with a sensed vertical acceleration. They proposed that the information on this acceleration is in the eye, with the other systems playing part including the non-vestibular proprioceptors and the vestibular system in general (4). The researchers who fronted the theory stated that the main causes of motion sickness have an underlying acceleration attribute, and can thus be accompanied by minor accelerations.

Evaluation and Prediction

Motion sickness is quantifiable. The physiological parameters used to quantify it are also helpful in the diagnosis and evaluation of the treatment measures (4). These parameters are also useful in the follow-up of the habituation process for the condition (4). Despite the need to use the parameters in motion sickness to assess the condition, the main challenge is in the quantification of the condition using symptoms.

According to Lackner (4), all the symptoms in motion sickness apart from vomiting are difficult to quantify. In fact, most of the earlier studies on the condition used vomiting and retching as the main factors in the diagnosis of motion sickness. The use of these symptoms limited the researchers. Thus, their findings were mainly unreliable since a small proportion of people experiences the two symptoms in the course of motion sickness only.

In the current studies on the condition, researchers use the two major symptoms along with other symptoms to diagnose motion sickness. The subjects in the studies have to provide the symptoms. Ordinal scales are then used to rank these symptoms (4). However, studies have concluded that the degree of motion sickness is dependent on the personal characteristics of the patients.

Field dependence, neurotism, and introversion are some of the personal characteristics that were highly associated with motion sickness (4). Other researchers found little correlation between the personality traits and motion sickness, with the suggestion of falsification of information by the participants (4).

The other path that has been followed in the prediction of motion sickness among the subjects is the use of Cortolis Sickness Susceptibility Index (CSSI) test for motion sickness.

The participants are required to move their head in a particular manner while seated on a rotating chair (4). In this test, the researchers found that the vestibular response in the patients susceptible to motion sickness was more intense than in the participants who had no history of the condition. This mode of evaluating the condition has been a resourceful one, with researchers using it examine the causation of the various motion sickness types

Visually Induced Motion Sickness

A Group f researchers (3) suggested three main classes of motion that are responsible for motion sickness. These classes may act either alone or in combination. They include, “low frequency translational accelerations, angular or cross coupling accelerations, or implied motion from the visual field (optokinetic)” (3).

Opokinetic stimulation, according to the researchers, causes less provocation to the sensory system compared to the real motion. They also state that the visually induced motion sickness occurs because of sensory mismatch or a sensory conflict, with the conflict existing between the visual and the somatosensory inputs (3).
Visually induced motion sickness is not as common as other forms of motion sickness.

The common types of visually induced sickness include the Cinerama and the sickness produced by playing video games (3). Golding et al. (3) state that the prevalence of the visually induced motion sickness is only 6% of the general population. This figure is significantly smaller than the other forms of motion sickness. The condition also has some of the mildest manifestation compared to the other forms of motion sickness. According to researchers (3), the prominent symptoms of motion sickness are not as common in the condition.

Despite the less severe manifestation of motion sickness induced by optokinetic stimuli, this class of motion sickness is increasingly causing distress among pilots and other people using aircraft simulators. The result of this situation is increased research into the condition. The other reason for the amplified exploration into the condition is the increasing use of head-mounted displays and the 3-D display in the entertainment devices that are increasingly becoming popular (3).

Apart from the methods described above for eliciting motion sickness, visually induced motion sickness may be induced using an optokinetic drum, which is a rotating drum in which the subject seats. Some of these instruments project the visual field in a manner that the subject interprets as if he or she is the one that is moving or rotating (3). Nausea is easily provoked by rotational frequencies of above 0.2 Hz. Other researchers, such as Mert and Bless (5), state this level as being significant for other stimuli inducing nausea.

Prevention and Treatment

The deterrence of healing of motion condition is an area that has been described in many literatures. The main intervention methods are either pharmacological or non-pharmacological. The treatment is also symptomatic. There are many interventions in use for the symptoms as they appear.

This section reviews the available procedures in the deterrence and cure of motion illness.
Non-Pharmacological treatment. The non-pharmacological treatments for motion sickness have their basis on the major theories that were proposed in the causation of the condition. Some of the treatment measures are meant to reduce conflicting sensory inputs as per the theory.

These inputs also accelerate multi-sensory adaptation while preventing the factors that aggravate nausea (4). These treatments are also aimed at enabling the subject to cope with the stimuli that are causing the motion sickness. They also help directly in the amelioration of the motion sickness.

Another treatment mode that was found to be beneficial in the reduction of motion sickness symptoms is the use of stroboscopic illumination. According to Lackner (4), this method works through the inhibition of retinal slip and causes a significant reduction in the symptoms.

Some researchers have also come up with some simple suggestions that can be useful in reducing the occurrence of motion sickness. They state that people who are known to experience the condition should avoid reading or any other tasks that require them to constantly change their visual fixation while travelling (4). The patients can also benefit from the use of cognitive behavior therapy and/or controlled regular breathing (2, 4).

Despite these methods being relatively effective, they are time consuming, with researchers proposing that they be applied to occupations that have frequent exposure to activities that induce motion sickness, including the army (4). Another method that has been deployed to thwart motion illness is acupressure. However, there are few positive findings in the literature supporting the use of this method. However, yachtsmen use acupressure.

Pharmacological Treatment. Pharmacological treatment for motion sickness is widely applied with travelers having prescriptions before they travel. The individual prevention and treatment of motion sickness depends on the personal characteristics. Hence, different treatments are used for different people.

Some of the significant factors in prevention and treatment of motion sickness include the susceptibility of the individual, the magnitude of the stimulus including its duration and the type, and the physical characteristics (2, 4). The occupation of the patient is also important since the medication has side effects that may limit the use in some groups such as pilots, drivers, navigators, and aviation crew.

The treatment of motion sickness is different from prevention. Different treatment methods are used for prevention and healing. Studies into the most effective chemical substances in the treatment of motion sickness have led to the development of two main classes of drugs.

These are the centrally acting anticholinergic and another class of drugs that enhance dopamine onorepinephrine activity (3, 4). The two classes of drugs have different receptor sites, with some of the receptors being located at the vestibular nuclei, the reticular formation, vomiting area, and the cerebellum.

Because of acting on the vomiting center, the drugs acting against motion sickness are also effective antiemetic substances. Various explanations exist on the actions of the medications. Researchers have attempted to explain how the two classes of drugs work, with those at the Naval Aerospace Medical Institute contributing significant in the explanation. Brainard and Gresham (1) state that the presence of provocative motion stimulus causes the central nervous system to react by transmitting vestibular impulses to the vestibular nuclei, cerebellum, and the reticular formation in the brain.

Competition between the noradrenergic and the acetyl cholinergic system neurons causes intermingling during the transmission of the impulses. Brainard and Gresham (1) state that the acetylcholine-mediated neurons directly stimulate the vomiting center by releasing a special neurotransmitter signal. On the other hand, the noradrenergic neurons are responsible for the stabilization of the condition, with a decrease in the symptoms.

The competition between the two classes of neurons discussed above has been the focus of influence in the prevention and treatment of motion sickness. The susceptibility of an individual to motion sickness can be influenced by the alteration in the nature of competition between the two classes of neuron (1).

The drugs used with an action on the two types of receptors have been put into use in the prevention and treatment of motion sickness. Those that block the cholinergic pathway include cyclizine, scopolamine, meclizine, atropine, dimenhydrinate, and promethazine (1). Sypathomimetics that are currently in use in the treatment of motion sickness include methylphenidate, phenmetrazine, d-amphetamine, and methamphetamine (1).

The availability of these drugs is dependent on their dosage forms. Different companies have made different formulations. Therefore, the drugs are available for oral, intramuscular, and suppository use, with the oral forms being taken at least an hour before the onset of the stimulus (1). In most cases of treatment of motion sickness, the route of administration that is mainly used is the intramuscular route. Scopolamine has been an extensively employed medicine in the curbing of motion infection.

The drug was originally available in the oral, bucal, and parenteral form. However, as Brainard and Gresham (1) reveal, the side effects associated with these routes of administration led to the development of a transdermal patch for the drug. The transdermal scopolamine is effective in the prevention of motion sickness over a 72-hour period.

The side effects associated with this route of administration are tolerable than other previously used routes (1, 4).
As described above, the transdermal patch of scopolamine is an effective method of prophylaxis against motion sickness. The only disadvantage to the use of the transdermal patch is that the effects are only felt 6 to 8 hours after the patch is applied (1). The oral form of the drug in significantly smaller doses is used to prevent the onset of motion sickness before the transdermal scopolamine takes effect.

The dose of oral scopolamine used in prophylaxis is significantly small to cause any significant side effects. Hence, its combination with the transdermal patch is an effective measure in prophylaxis. Despite the transdermal route causing lower incidences of scopolamine side effects, repeated or prolonged use of this form of the drug may cumulatively lead to the development of the undesired side effects (1).
Another form of administration that has recently been developed by the German Airforce Institute is the scopolamine nasal spray (4).

This form of administration has been described as very effective, safe, and with a rapid onset of treatment effects. Many other treatment forms are currently being investigated, with the army institutions all over the world leading in the search for the drug that will rid them of this commonly occurring condition in their aviators. Histamine is a chemical that has been studied in the pathophysiology of motion sickness.

Its main role is in the peripheral vestibular apparatus where there is activation and maintenance of a firing mechanism. Lackner (4) states that the role of histamine is to increase the rate at which the afferent nerves fire from the semicircular canal ampullae. The chemical has been the target of recent drugs that are aimed at preventing motion sickness. These drugs antagonize the action of the chemical at the H1 receptors. They are effective in the prevention of motion sickness.

Material and Methods

This research is an article review. It combines the knowledge gathered from different scientific works to reach the desired conclusions. An article review is a good way to answer the study objectives. The advantages of using this method include saving resources and time while providing strong conclusions based on the findings of other researchers.

The research involved a search of the relevant literature from a medical database. With the location of the appropriate medical database, keywords were used to search the required literature works. Some of the key words included motion sickness, aerospace medicine, treatment, and countermeasures.

The results of the search were refined, with those appropriate for this research being selected. Analysis of the references of the selected literatures was later done. The writer did a search to evaluate whether the references will be applicable to the research. The initial literature search produced 39 results. A further refining of the search produced 19 relevant articles, which were then organized using a relevant criterion to ensure that they were useful for the research review.

The inclusion criteria used in the articles selection included the requirement that the literature was in English, with the exclusion criteria featuring those written in other languages. After the application of this criterion, the final list of articles resulted in 17 relevant literature. However, these articles provided the best resources on motion sickness, prevention, and treatment. They were relevant in this research.

Results

Stroboscobic Light as a Treatment of Motion Sickness

Research has shown that the use of stroboscopic room illumination led to reduced motion sickness incidents in people who were predisposed to the condition because of visual vestibular conflict.

Webb, Estrada, and Athy (8) state that unlike previous researchers that were able to demonstrate the absence of motion sickness in stroboscopic conditions, their research showed minor symptoms of the same if image reversal was effected in the patients (8). In their research, there was a conclusion that stroboscopic illumination was applicable in dropping the rigorousness of the signs of motion illness.

Webb, Estrada, and Athy (8) also supported the use of this form of countermeasure and concluded that stroboscopic illumination appears to be an effective countermeasure where retinal slip is a significant factor in eliciting motion sickness due to either self-or surround-motion. Scholars (8) also observed the use of stroboscopic light as being a significant countermeasure for motion sickness.

They observed that vision reversal in stroboscopic light caused modification in the oculomotor control. As a result, there was the absence of motion sickness during this period. They further defined a special range of the frequency spectrum to which vision reversal was restricted in the elimination of motion sickness.

Webb, Estrada, and Athy (8) also supported the use of stroboscopic light in the prevention of motion sickness. However, the application of the technology in the prevention of motion sickness was restricted to use in air transport, with few researchers utilizing it on other forms of transportation inducing motion sickness.

The use of stroboscopic illumination as a non-pharmacological treatment of motion sickness is also restricted to motion sickness caused by retinal slip (8). However, this countermeasure is described as being an efficient one. The researchers recommend the development of special technology to make its use easier (8).

Habituation and Adaptation Training for Motion

The use of habituation and adaptation as effective non-pharmacological countermeasures has been attempted in many instances. Mert and Bless (5) state that desensitization programs have been used in the prevention of motion sickness in aircrew. Habituation can be achieved from provocative vestibular stimulation, with this stimulus being transferred to a less provocative environment. The development of motion sickness during the simulation in aerospace engineering has also been reduced through desensitization.

Adaptation training has showed significant results in this field, with unrelenting G flight replication being used to augment the efficiency of the simulation (6). However, adaptation training is effective only if there is frequent repetition of the motion. Newman et al. state that the benefits from this therapy may not be lost in gaps less than 2 weeks between training (6).

Coriolis effect is recognized in the causation of motion sickness (6). A traditional view is that hyperventilation has a role to play. However, there is also indication that no relationship exists between hyperventilation and nausea in Coriolis effects. The desensitization programs have always monitored the cardiorespiratory system.

Nevertheless, this finding makes the monitoring unessential during desensitization. Pilot desensitization programs should use the monitoring of the cardiorespiratory system in cases where the motion sickness is intractable. This method is dependent on the individual susceptibility.

Acupressure and Acustimulation Bands

Acupressure and acustimulation have also been studied in relation to their efficiency in the deterrence of motion disease. In acupuncture, the specialists stimulate points in the various body meridians using special needles. One has to be a trained acupuncturist to know these points (2). Specialists use this technique to control the symptoms of motion sickness. One of the most commonly used sites is the Neiguan point, also known as the P6 point. This point is recognized in the control of vomiting and nausea (2).

Located between the tendons of two muscles in the arm, the point is stimulated to control the prevalence of vomiting in patients with the symptoms of nausea or vomiting in motion sickness. Researchers (2) observed efficacy in the reduction of the symptoms of motion sickness when there was acustimulation of the above point, especially in the experiment that was conducted in the optokinetic drum exposure. Some devices are already in use for treatment of motion sickness through the application of acupressure and acustimulation.

These are the Acuband® and the ReliefBand® (2). However, Cox, Singh, and Cox (2) state that these devices demonstrated low efficacy in treatment. The use of the above devices in accordance with the directions of the manufacturer was found to be ineffective even when the right procedures were applied. The researchers state that the use of the interventions is effective if applied accurately.

Pharmacological Agents

The use of pharmacological treatment for motion sickness is widely applied, with many researchers stating the effects of these measures. The balance between the cholinergic and noradrenergic systems has been exploited in the medical treatment of motion sickness (4).

Scopolamine is the most widely used drug in the treatment of motion sickness. Many forms have been used including the oral, bucal, and nasal preparations. The antihistamines acting on the different receptors also cause alleviation of the symptoms of motion sickness, with the effects being felt in all the populations (4).

According to Brainard and Gresham (1), centrally acting anticholinergic and dopamine enhancing drugs are effective in the treatment of motion sickness. The medication is also effective against vomiting, which is one of the most severe presentations of motion sickness (1).

These drugs have been associated with the effects on the neuronal systems that control the act of vomiting and stabilization in motion sickness. Scopolamine is among the cholinergic blockers that are useful in the treatment of motion sickness, with the other useful drugs being atropine, cyclizine, and meclizine (1). The analysis of the use of Modafinil in the treatment of motion sickness concluded that the drug was more effective than a placebo that was given in other participants of the study.

Modafinil is a drug whose mechanism of action remains unknown, although it has been found to be as effective as dextroamphetamine in the treatment of narcolepsy. Scopolamine remains the most effective pharmacological treatment for motion sickness (1).

Research by Schmäl (7) into alternative drugs has been prompted by the side effect profile that the drug has including reduced psychomotor performance and increased dizziness that may be exaggerated. However, the use of transdermal patches of the drug has been discussed as an important part of reducing the side effects. Brainard and Gresham (1) also state the developments in the use of scopolamine nasal spray with reduced side effect profile.

Discussion

According to this research, the treatment of motion sickness can take a multidimensional approach, with a division into pharmacological and non-pharmacological interventions. The review establishes that the use of stroboscopic light in the non-pharmacological countermeasures is effective in preventing motion sickness (8). In the reviewed research articles, the researchers evaluated the use of this technology in the prevention of motion sickness.

The results in most of these studies were positive, with a marked reduction in the severity of the condition and symptoms that are commonly seen (8). The only limitation to the use of this countermeasure is the instance where it may be used. The researchers attribute the most efficacy of the countermeasure to the motion sickness caused by retinal slip. The future application of the countermeasure is promising. There should be an application in the aerospace engineering where this form of motion sickness is mainly experienced.

Although the use of acupressure and acustimulation has been documented in several areas, the research finds that the countermeasures were not effective in the alleviation or prevention of motion sickness (2). Studies that are consistent with these methods concluded that the improvements in techniques used to administer the acupressure and acustimulation will not lead to any gains in the control of motion sickness (2). The use of these countermeasures was mainly in mainland China. Few people have managed to use them successfully. The application will also be involving and time consuming.

Habituation and adaptation training have also been discussed as a major component in the treatment of motion sickness. The research shows that these measures can be effective, with only a few limitations (1, 6). The duration of the effects of these measures of preventing motion sickness is not as long as the other measures. They present an expensive way of motion sickness prevention (6). They involve exposure to the stimulus causing motion sickness, with the adaptation and eventual reduction in the symptoms.

The pharmacological treatment of motion sickness remains the most useful countermeasure, with most of the researches supporting this notion (1). The various types of medication methods that have been discussed as effective in the treatment of motion sickness are based on the balance between the main hormones in the sympathetic and parasympathetic systems (1).

Scopolamine remains the most effective of all drugs in the prevention and treatment of motion sickness (1). The drug is effective in many forms. However, the form that has traditionally been used is buccally available oral medication (4). However, this route of administration has been discussed as being accompanied by many side effects (1).

The side effect profile of Scopolamine includes vomiting, retching and fever, which can be distressing to the patient. The use of transdermal patches in combination with small oral doses has been found to be effective, with reduction of the main side effects (1). Scopolamine is also available as a nasal spray with other forms being investigated.

Some of the other drugs that are available in the treatment of motion sickness include promethazine, d-amphetamine, meclizine, and dimenhydrinate (7). These drugs have the common characteristic of causing adverse effects including reduced psychomotor performance and sleepiness. The drugs that are not associated with impairment in psychomotor performance include promethazine and d-amphetamine.

Hence, aircrew people can use them without much disturbance to their function (7). The efficacy of these drugs is also dependent on the individual and drug characteristics. The application of oral meclizine and cyclizine is also associated with the reduction in the number and severity of side effects. Therefore, these drugs can be combined with the conventional drugs to provide an added advantage in reducing the side effects.

Motion sickness is mainly evident in aircrew. The environment where these people work in is the main predisposing factor in the development of the condition. Most of the roles played by the aircrew and the aviators are intense, requiring their strict involvement. The above-suggested drugs, especially scopolamine, have associated side effects that are not desirable to any individual or organization in such a profession.

The addition of other drugs such as pseudoephedrine and d-amphetamine to the conventional motion treatment regimens provides a significant reduction in the side effect profile for these drugs (7). Therefore, this study establishes the countermeasures in motion sickness, with pharmacotherapy being the most effective. However, there is a need for more research into some of the countermeasures such as stroboscopic illumination to evaluate their use in the future treatment regimens.

The use of scopolamine remains the most widely studied topic in the treatment of motion sickness. There are few publications detailing the effects of combination of the non-pharmacological and the pharmacologic countermeasures for motion sickness.

The future studies should focus on the combination of the two to provide any conclusions on the efficacy of combination. The future studies should also study the efficacy of acupuncture in a standardized environment. The limitations to this study included the availability of few literature materials on the topic.

Conclusion

Motion sickness continues to be a big problem for the transportation industry, with modern forms of transportation being mostly affected. Research has allowed the prediction of motion sickness, with mathematical calculation being an important contributor to this situation.

The reviewed research papers show the various variables and parameters in the measurement of motion sickness. There is a marked improvement from the traditional use of vomiting alone. The pathophysiology of the condition also continues to elicit research, with one of the most important findings being the role of otoliths in the causation of the condition. Several theories have also been developed in the pathophysiology.

The improvements in the measures of evaluation of motion sickness have led to the development of further theories on the pathogenesis. This paper looked at the different countermeasures in the treatment of motion sickness. The two classes are the pharmacological and non-pharmacological categories. The non-pharmacological measures are insufficient in the prevention and treatment of the condition. These measures include habituation and adaptation training, stroboscopic light use, and acustimulation.

Pharmacological treatment of motion sickness is discussed as being the most effective countermeasure. The researchers stated the different medication in the treatment of motion sickness. It is largely utilized in the aviation industry. The available forms are the oral, parenteral, and topical preparations.

The side effects are the main hindrances in the use of any of the motion sickness drugs, as they are often associated with vomiting, retching, and nausea among others. The prevention of these side effects is possible with the use of transdermal preparation of the drug. The use of oral cyclizine and meclizine is also associated with reduced side effects. The combination of these drugs with the conventional drugs has an added advantage.

References

1. Brainard A, Gresham C. Prevention and treatment of motion sickness. American Family Physician. 2014;90(1):41-46.
2. Cox DJ, Singh H, Cox DM. Effectiveness of acupressure and acustimulation in minimizing driving simulation adaptation syndrome. Military Medicine. 2011;176(12):1440-1443.
3. Golding JF, Doolan K, Acharya A, et al. Cognitive cues and visually induced motion sickness. Aviation, Space, and Environmental Medicine. 2012;83(3):477-482.
4. Lackner JR. Motion sickness: more than nausea and vomiting. Experimental Brain Research. 2014;232:2493-2510.
5. Mert A, Bless W. Impact of alignment to gravito-inertial force on motion sickness and cardiopulmonary variables. Aviation, Space, and Environmental Medicine. 2011;82(7):694-698.
6. Newman MC, Mccarthy GW, Glaser ST, et al. Motion sickness adapation to Coriolis-inducing head movements in a sustained G flight simulator. Aviation, Space, and Environmental Medicine. 2013;84(2):104-109.
7. Schmäl F. Neuronal mechanisms and the treatment of motion sickness. Pharmacology. 2013;91(3-4):229-241.
8. Webb CM, Estrada A, Athy JR. Motion sickness prevention by an 8-hz stroboscopic environment during air transport. Aviation, Space, and Environmental Medicine. 2013;84(3):177-183.