The Five Senses and Beyond: The Encyclopedia of Perception - Jennifer L. Hellier 2017

Motion Sickness

Motion sickness is a multifaceted condition in which a person experiences several unpleasant symptoms during actual or sensed motion. It is a common problem that has been recognized for hundreds of years. During biblical times, it was known as “camel sickness” as that was one of the main forms of travel and often made people feel sick. When travel by sea became prevalent, it was known as seasickness. The word nausea is derived from the Greek word naus meaning ship.

Causes and Risk Factors

The cause of motion sickness is complex and not entirely understood. The brain senses motion using several signaling pathways. These include the inner ear, eyes, and special receptors called proprioceptors. The inner ear contains the vestibular system, which includes three semicircular canals, saccule, and utricle. The function of these organs is to sense motion, spatial orientation, and other sensory information, and they also play a role in maintaining equilibrium. Motion sickness is believed to occur when the different signaling pathways have conflicting sensory information when exposed to a motion stimulus. This creates a conflict in sensory input to the brain, which creates abnormal sensory processing.

Anyone can be affected by motion sickness, although some people are more likely to be affected than others. There is no direct way to guess who will be affected; however, there are some factors that can increase the possibility of becoming motion sick. Those more likely to be prone to motion sickness include (1) women (especially those who are pregnant); (2) children, usually between the ages of 5 and 12; (3) people who have migraines or other conditions such as ear infections or conditions that interfere with the vestibular system in the ear; and (4) athletes. Young children under the age of two are typically not affected, and the likelihood is reduced in the elderly. Other factors that can make someone more likely to experience motion sickness are lack of sleep, anxiety and stress, alcohol, smoking, and eating large meals. People react differently to motion sickness and some may be more likely to get sick from one type of activity while others will be affected more by another.

Types and Symptoms

There are many different types of motion sickness, or type of motions that can make one get motion sick. Some things or activities that can elicit symptoms include cars (carsickness), airplanes (airsickness), trains, rides (such as those at amusement parks), boats or ships (seasickness), video games, simulators, space motion sickness, and virtual reality sickness.

There are numerous signs and symptoms of motion sickness. These include a general unwell feeling, headache, nausea, vomiting, sweating, dizziness, “stomach awareness,” increased salivation, burping, difficulty concentrating, fatigue, confusion, irritability, and pale skin. The most common symptom is nausea. The signs and symptoms can occur soon after experiencing the motion or it may take a while for them to develop. Symptoms will usually subside after the motion stops, but sometimes they can persist for several hours or days afterward. The severity of symptoms may vary widely, and again each person is different. Once a person experiences motion sickness, he or she is more likely to develop it again.

Diagnosis

There are no specific diagnostic tests for motion sickness. However, sometimes tests need to be performed in order to exclude other causes, such as vertigo and pregnancy. Tests performed in these situations may include a pregnancy test, computed tomography (CT) or magnetic resonance imaging (MRI), and vestibular testing. Motion sickness is not normally a cause for worry, except if the symptoms, especially vomiting, last for more than a few days. Continued vomiting can cause dehydration, electrolyte imbalances, low blood pressure, and irregular heartbeats.

Treatments

There are several ways in which to treat motion sickness including medications and behavioral modifications. Medications work best if taken before exposure to the motion stimulus occurs. It is much easier to prevent motion sickness than to treat the symptoms once they have already begun. Current motion sickness medications include anticholinergics (scopolamine), antiemetics (Zofran), antihistamines (Benadryl, Antivert, Bonine, and Dramamine), antidopaminergics (Phenergan and Zofran), and bendodiazepines (Valium). Scopolamine is probably the most effective and its effects last several days. Scopolamine usually comes as a patch, which is applied behind the ear. Many of these medications have similar side effects, which include a dry mouth, drowsiness, and blurry vision. Less common side effects include constipation, bloating, headache, and confusion. Other treatments include eating specific foods (such as crackers), getting fresh air, acupressure (at the P6 pressure point on the wrist), and eating ginger. Behavioral modifications include lying down, keeping eyes fixed on the horizon, sitting in the front seats of cars, and standing in the middle of a boat. Further research is needed to focus on the treatment of motion sickness. Medications that do not have the adverse side effects such as drowsiness and those that treat both nausea and vomiting are needed.

Shannen McNamara

See also: Dizziness; Emesis; Nausea; Vestibular System; Visual Motor System

Further Reading

Brainard, Andrew, & Chip Gresham. (2014). Prevention and treatment of motion sickness. American Family Physician, 90(1), 41—46. Retrieved from http://www.aafp.org/afp/2014/0701/p41.html

Lackner, James R. (2014). Motion sickness: More than nausea and vomiting. Experimental Brain Research, 232(8), 2493—2510.