Motion Sickness
BASICS
DESCRIPTION
- Motion sickness is a physiologic response in affected individuals to a situation in which sensory conflict about body motion exists among visual receptors, vestibular receptors, and body proprioceptors.
- Often induced when patterns of motion differ from those previously experienced or expected
- Differs from “cybersickness” or “virtual reality sickness” (symptoms, including dizziness, that result from exposure to computer based stimuli) in the fact that some form of actual movement is generally required to diagnose motion sickness
- Systems affected: nervous, gastrointestinal
- Synonym(s): car sickness; sea sickness; air sickness; space sickness; physiologic vertigo; kinetosis
EPIDEMIOLOGY
- Females are more likely to be affected than males (1)[ ].
- Pregnancy increases risk (possibly secondary to hormonal changes).
- Children <2 years of age unlikely to be affected, although highest incidence in children 6 to 12 years of age
Prevalence
Estimation is complex although motion sickness is a common physiologic phenomenon that can develop in any individual with the right conditions. Estimations of prevalence vary widely by activity, from <1–1% of those riding in cars, trains, or pressurized commercial aircraft to 25% of those traveling on large ships up to 80% of astronauts during their first 3 days of space travel (1)[ ].
ETIOLOGY AND PATHOPHYSIOLOGY
- Precise etiology unknown; thought to be due to a mismatch of vestibular and visual sensations, particularly those to which an individual has not been habituated
- Rotary, vertical, and low-frequency motions produce more symptoms than linear, horizontal, and high-frequency motions (2)[ ].
Genetics
Heritability estimates range from 55% to 75% (1)[ ].
RISK FACTORS
- Motion (auto, plane, boat, amusement rides)
- Visual stimuli (e.g., moving horizon)
- Poor ventilation (fumes, smoke, carbon monoxide)
- Emotions (fear, anxiety)
- Zero gravity
- Pregnancy, menstruation, oral contraceptive use
- History of migraine headaches, especially vestibular migraine
GENERAL PREVENTION
See “General Measures.”Pediatric Considerations
- Rare in children <2 years of age
- Incidence peaks between 6 and 12 years of age.
- Antihistamines may cause paradoxical agitation in children.
- Scopolamine should be avoided in children
Geriatric Considerations
- Age confers some resistance to motion sickness.
- Elderly are at increased risk for anticholinergic side effects from treatment.
Pregnancy Considerations
- Pregnant patients are more likely to experience motion sickness.
- Scopolamine should be avoided in patients with severe preeclampsia due to increased risk of eclamptic seizures.
COMMONLY ASSOCIATED CONDITIONS
- Migraine headache
- Vestibular syndromes
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