Pathophysiology and Treatment of Motion Sickness
In an extensive survey of a cruise ship, motion sickness was the most common reason for physicians' consultations, the incidence of 4.2 per 1000 person/days being higher than for infections or injuries. Up to a quarter of codrivers became motion sick in rally cars if they were reading a book or sitting in the back seat. Although motion perception sensitivity to off-vertical axis rotation increased immediately after return from spaceflight compared to prespaceflight, motion sickness susceptibility decreased. Vection can be induced using auditory cues, although weaker than visually induced vection, and unlike visual motion, auditory cues for motion fail to produce sickness. The addition of body loads while standing can modulate both postural sway and motion sickness induced by visual motion. Watching 3D stereoscopic video films provokes more motion sickness than 2D videos. By contrast, another study in both adults and children found only low levels of sickness, with no clear differences between 2D versus 3D, and concluded that use of a stereoscopic 3D system for up to 2 hours was acceptable for most users regardless of age.
With vehicular movement, nauseogenicity peaks at a mechanical frequency of around 0.2 Hz, and this has also been shown true for exposure to oscillating visual field motion. Hypotheses for the frequency dependence of nauseogenicity include a phase error in signalling motion between canal–otolith and somatosensory systems, or a frequency-dependent phase error between the sensed vertical and the subjective or expected vertical. It has also been proposed that a zone of perceptuomotor ambiguity around 0.2 Hz triggers sickness, because at higher frequencies, imposed accelerations are usually interpreted as translation of the self through space, whereas at lower frequencies, imposed accelerations are usually interpreted as a tilt in the gravitoinertial force (GIF) vector. The region of 0.2 Hz would be a crossover between these two interpretations and, thus, a frequency region of maximal uncertainty concerning the appropriate frame of reference for orientation. A related 'ecological' explanation has been proposed that this frequency tuning is related to mechanical limitations on human body motion. This proposes that a cause of motion sickness may be the difficulty in selecting appropriate tactics to maintain body stability at vehicle motion circa 0.2 Hz, between whole-body GIF alignment, seen at lower frequencies, versus lateropulsion, seen at higher frequencies.
Provocative Circumstances
In an extensive survey of a cruise ship, motion sickness was the most common reason for physicians' consultations, the incidence of 4.2 per 1000 person/days being higher than for infections or injuries. Up to a quarter of codrivers became motion sick in rally cars if they were reading a book or sitting in the back seat. Although motion perception sensitivity to off-vertical axis rotation increased immediately after return from spaceflight compared to prespaceflight, motion sickness susceptibility decreased. Vection can be induced using auditory cues, although weaker than visually induced vection, and unlike visual motion, auditory cues for motion fail to produce sickness. The addition of body loads while standing can modulate both postural sway and motion sickness induced by visual motion. Watching 3D stereoscopic video films provokes more motion sickness than 2D videos. By contrast, another study in both adults and children found only low levels of sickness, with no clear differences between 2D versus 3D, and concluded that use of a stereoscopic 3D system for up to 2 hours was acceptable for most users regardless of age.
With vehicular movement, nauseogenicity peaks at a mechanical frequency of around 0.2 Hz, and this has also been shown true for exposure to oscillating visual field motion. Hypotheses for the frequency dependence of nauseogenicity include a phase error in signalling motion between canal–otolith and somatosensory systems, or a frequency-dependent phase error between the sensed vertical and the subjective or expected vertical. It has also been proposed that a zone of perceptuomotor ambiguity around 0.2 Hz triggers sickness, because at higher frequencies, imposed accelerations are usually interpreted as translation of the self through space, whereas at lower frequencies, imposed accelerations are usually interpreted as a tilt in the gravitoinertial force (GIF) vector. The region of 0.2 Hz would be a crossover between these two interpretations and, thus, a frequency region of maximal uncertainty concerning the appropriate frame of reference for orientation. A related 'ecological' explanation has been proposed that this frequency tuning is related to mechanical limitations on human body motion. This proposes that a cause of motion sickness may be the difficulty in selecting appropriate tactics to maintain body stability at vehicle motion circa 0.2 Hz, between whole-body GIF alignment, seen at lower frequencies, versus lateropulsion, seen at higher frequencies.