Motion sickness: advances in pathogenesis, prediction, prevention, and treatment.

Motion sickness has a major influence on modern traveling activities and the rapidly spreading engagement in virtual reality immersion. Recent evidence emphasizes the role of the otoliths in the pathogenesis of motion sickness, and several new theories may help explain its occurrence beyond the traditional sensory conflict theory. A promising new direction is the recently reported association of genetic polymorphism of the alpha2-adrenergic receptor with increased autonomic response to stress and motion sickness. Various physiological measures for the evaluation and prediction of motion sickness have been tested. However, no single parameter has yet been found to be of high enough sensitivity and specificity for the diagnosis or prediction of individual motion sickness susceptibility. A number of pharmacological and non-pharmacological countermeasures are used for the prevention and treatment of motion sickness. The non-pharmacological options include all procedures that reduce conflicting sensory input, accelerate the process of multi-sensory adaptation, and promote psychological factors which enable the subject to cope with his/her condition. The most effective anti-motion sickness drugs are central acting anticholinergics and H1 antihistamines; however, adverse effects on psychomotor performance may limit their use in drivers, pilots, and naval crewmembers. Recent studies may be relevant to our understanding of the link between motion sickness, migraine, vertigo, and anxiety. Based on these findings and on recent neurochemical data, the development of new anti-motion sickness agents is a promising field of investigation.