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Motion Sickness
Timothy C. Hain, MD 
Page last modified:
December 13, 2011
Motion sickness is the nausea, disorientation and fatigue that can be induced by head motion. The first sign is usually pallor. Yawning, restlessness and a cold sweat forming on the upper lip or forehead often follow. As symptoms build, an upset stomach, fatigue or drowsiness may occur. The final stages are characterized by nausea and vomiting.
Motion sickness is common and normal. Nearly anyone can be made motion sick by an appropriate stimulus, except for individuals with no vestibular system (William James). In a large study done in India, the prevalence of motion sickness was about 28%, and females were more susceptible (27%) were more susceptible than males (16.8%). Individuals with more active occupations are less susceptible (Sharma, 1997). In medical transport personnel, 46% of personnel reported nausea and 65%, the sopite syndrome (sleepiness caused by motion). (Wright, 1995)
Horses, cows, monkeys, chimpanzees, birds and sheep have been reported in scientific publications to show motion sickness. Rats, unfortunately I suppose, do not vomit so cannot serve as experimental subjects.
According to Benson, nearly 100% of (human) occupants of life rafts will vomit in rough seas. 60% of student aircrew members suffer from air sickness at some time during their training. For vertical motion (heave), oscillation at a frequency of about 0.2 hz is the most provocative. Motion at 1 Hz is less than 1/10th as provocative. About 7% of seagoing passengers report vomiting during a journey (Lawther and Griffin, 1988).
Women are more sensitive to motion than men, by a ratio of about 5:3, although this may be related to reporting differences rather than true physiological differences( Cheung, B. and K. Hofer , 2002). Women are more sensitive to motion around the times of their menstrual cycle (Glunfeld and Gresty, 1996). This may be due to interactions between migraine and motion sickness.
Children are said to be almost immune to motion sickness up to the age of 2. As children grow older, the severity of motion sickness increases up to roughly the age of 15 (Takahasi et al, 1994). In our dizziness practice, we have noticed women of childbearing age become more motion sickness as their migraine tendency increases.
There are certain illness that eliminate motion sickness. These include bilateral loss of inner ear function (William James, the pragmatist philospher), and lesions of the cerebellar nodulus (Bard).
What Causes Motion Sickness ?
In order for the body to determine where it is at all times, the brain combines visual information, touch information, inner ear information, and internal expectations. Under most circumstances, the senses and expectations agree. When they disagree, there is conflict, and motion sickness can occur.
For example, consider the situation when one is reading in the back seat of a car. Your eyes, fixed on the page, say that you are still. However, as the car goes over bumps and accelerates/decelerates, your ears disagree. This is why motion sickness in this situation is common.
Acquired susceptibility to motion sickness occurs occasionally. Persons with an inner ear disturbances, especially a recent one, may be intolerant to activity in general. People with migraine are apt to get motion sick. Persons with rare, central nervous system disorders of the part of the brain that processes signals from the inner ear may also be unusually susceptible to motion sickness. Certain individuals who are constitutionally susceptible to motion sickness and can develop sea sickness on ships, and a prolonged land sickness, when they get off the ship. This rare disorder is called "mal de debarquement", which is French for "bad getting off the ship". Persons with unusually good vestibular function may be more susceptible to motion sickness than others (Gordon et al, 1996).
Migraine is a definite risk factor for motion sickness, with roughly a 5 fold greater incidence than non-migraineurs. Female gender and youth is also a risk factor. In women, days 9-15 of the menstrual cycle appear to have a higher incidence of nausea (Grunfeld and Gresty, 1999; Ramsay, 1994) but not all agree (Cheung, B., R. Heskin, et al. 2001). Medications that prevent migraine may also prevent motion sickness (see below).
The space-military industrial complex has developed a peculiar theory of motion sickness that depends on asymmetry in otoconial mass (Scherer et al, 1997). Perhaps this mechanism is applicable in outer space, but it seems to us to have very little relevance to "down to earth".
Experimentally, motion-sickness can be eliminated in dogs by surgically removing part of the brain (the nodulus, according to Bard). Motion sickness is sometimes associated with prolonged vestibular responses (Hoffer et al. 2003).
Motion sickness immunity is generally found in persons with absent vestibular responses (William James; Cheung et al. 1991). Age is probably not a large factor in motion sickness (Cheung and Money, 1992) although children below the age of 2 are said to be immune.
There are three strategies to treat motion sickness:
When all three strategies are used, it is extremely uncommon to find a person who does not get substantially better.
Behavioral Strategies for Motion Sickness
One can often avoid motion sickness by anticipating the motion. Drivers have much less motion sickness than passengers, because they are controlling the motion, and know when they are turning, starting and stopping. Drivers on familiar routes are less prone to getting motion sick than drivers in new territory.
Medication
for Motion Sickness
Most medications for motion sickness need to be taken at least 30 minutes before exposure to the activity that can cause the problem. Persons with glaucoma or prostate problems should not take most of these medications unless so advised by their doctor.
We so far have neverrarely an individual who could not avoid motion sickness by pretreating with klonapin and ondansetron. That being said, here are more details.
Medications for nausea and vomiting
Treatment of motion sickness differs from treatment of nausea and vomiting. A discussion of the treatment of vomiting can be found here.
It is reasonable to assume that habituation (repeated motion exposure) makes one less motion sensitive. (Cheung, B. and K. Hofer, 2005). In fact, the military uses a "habituation" protocol to overcome motion sickness. This requires expensive equipment (a rotating chair).
A somewhat similar approach was reported by Dai et al recently, in a civilian apparatus. It again involved a rotatory chair as well as a simultaneously rotating optokinetic surround. In our practice in Chicago, we are attempting to implement this protocol with our own equipment.
Habituation can be obtained through sports activities or physical therapy procedures. These procedures generally involve use of visual-vestibular mismatches, called "times 2" and "times 0" viewing. Stimulators with "disco balls" are often used too.
The recently has been a new home exercise method proposed to overcome motion sickness -- the "Puma" method. These exercises were developed by a flight surgeon (Sam Puma), to assist pilots with motion sickness in overcoming their sensitivity to motion. They are very stimulating exercises, that may be useful to extremely motivated people, who are not able to use more conventional methods of management of motion sickness such as medications
The Puma method appears to us to be a habituation protocol -- repeated exposure to the things that make one ill. This may well work -- if you can tolerate the process. We are cautiously hopeful about this method -- although it seems to us to be likely to cause a lot of nausea itself. If you are interested in trying the Puma exercises, you can order a copy through this link. When we suggest this to our patients in our dizziness practice, we suggest that they use ondasetron to avoid nausea.
Our thought is that activities that promote formation of "internal models" of motion may also be useful for motion sickness prevention. We do not know of any formal protocols that use this idea.
We recently have proposed a protocol for visual dependence that may be useful in treatment of motion sickness (Chang and Hain, 2007). See the page on visual dependence for more detail.
There are numerous "alternative" remedies for motion sickness. The most popular are Ginger derivatives, such as ginger tea, powdered ginger capsules, and even raw ginger between the teeth. We have not seen much success in our patients. Holtman et al(1989) reported no effect on vestibular responses by ginger, and suggested that Ginger's main effect is on the stomach, to prevent vomiting.
Acupuncture and acupressure has been reported useful for motion sickness. It appears to be a little better than placebo.
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