Space Motion Sickness and Motion Sickness: Symptoms and Etiology

Montclair Stat University, Montclair, NJ, USA.
Aviation Space and Environmental Medicine (Impact Factor: 0.88). 07/2013; 84(7):716-21. DOI: 10.3357/ASEM.3449.2013
Source: PubMed


The adverse symptoms of space motion sickness (SMS) have remained problematic since the beginning of manned spaceflight. Despite over 50 yr of research SMS remains a problem that affects about half of all space travelers during the first 24-72 h of a spaceflight. SMS has been treated as another form of motion sickness (MS) despite distinct differences in symptomology. In this review SMS and MS differences are examined and documented based on available data. Vestibular biomechanics that occur during weightlessness coupled with theoretical assertions regarding human evolution have led us to propose a two-component model of SMS. The first component involves conflicting sensory signals inherent to the otolith organs that occur during weightlessness. The second component is a bimodal conflict between the otoliths and semicircular canals that can occur during normal head movements in weightlessness. Both components may inadvertently, and mistakenly, signal that a vestibular malfunction has occurred, hence initiating a protective mechanism that may produce symptoms that discourage activity.

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Available from: Frederick Bonato, Dec 18, 2013
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    • "In addition, motion sickness is often linked with the Sopite syndrome, whose symptoms include lethargy and drowsiness (Graybiel and Knepton 1976). As noted in the introduction, motion-induced nausea and vomiting occur most often when sensory feedback related to movement deviates from that which is expected, which requires a comparison of the sensory signals with the motor plan (Lackner and Dizio 2006; Thornton and Bonato 2013). Hence, the neural pathways that trigger emesis during motion are likely more complex than those that elicit vomiting following exposure to toxins or stimulation of GI afferents. "
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    • "During the initial days of the missions, the astronauts, however, did become motion sick simply by virtue of making head and body movements. Being in a weightless environment alters the sensory motor control of the head as an inertial mass, and we now know that such alterations are provocative per se (Lackner and DiZio 1989, 2006; Lackner and Graybiel 1980, 1986b; Oman 1987; Oman et al. 1986, 1990; Thornton and Bonato 2013). This altered control and need to recalibrate are a major factor in space motion sickness and terrestrial motion sickness experienced in vehicles as well. "
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