Motion Sickness

Motion sickness is induced during passive locomotion in vehicles and is generated either by unfamihar bodily accelerations, to which the person has therefore not adapted, or by intersensory mismatch involving conflicting vestibular and visual stimuli (Dichgans and Brandt 1973, 1978; Benson 1977; Reason 1978; Brandt and Daroff 1980). According to the “mismatch theory”; (see also p. 3), spatial orientation and perception of movement are disturbed by a conflict between stimuli when the multisensory motion signals do not correspond to the expected pattern of sensory signals established from earlier experience with active locomotion. This may give rise to unpleasant illusions of movement with consequences of posture and the control of vehicles (Dichgans and Brandt 1978; Leibowitz et al. 1982) and to motion sickness as a result of summation. Thus, motion sickness is not a superfluous epiphenomenon of vestibular stimulation but — in a teleological sense — it represents a meaningful warning signal to withdraw the body from unusual stimulus situations which cannot be integrated with adequate dynamic spatial orientation. The first known reports on seasickness originate from Hippocrates. The major symptom of nausea is derived from the Greek word “naus” for ship. The general term “motion sickness” was coined by Irwin (1881). It stresses the phenomenological similarity of air-, sea-, car-, and space-sickness despite their different modes of provocation.