Dear Sirs,

Motion sickness is a clinically and scientifically relevant topic. According to a Medline Search, 5768 articles use the terms “motion sickness” or “kinetosis” (date 13-05-2018). Its underlying mechanism is best explained by an intersensory mismatch involving conflicting vestibular, visual, and somatosensory stimuli [1, 2]. The typical signs and symptoms of initial dizziness, physical distress, fatigue, yawning, facial pallor, oversensitivity to smells, sweating, headache and, once fully developed, nausea and vomiting with apathy and fear of annihilation [3] were already described in ancient Greek and Roman literature [4]. The prevalence of motion sickness is higher in certain vestibular disorders like vestibular migraine due to hypersensitivity to sensory input and is lower in others like bilateral vestibulopathy because the vestibular input is diminished, resulting in less visuo-/somatosensory, vestibular mismatch [5,6,7,8].

The objective of this epidemiological study was to evaluate the prevalence of motion sickness in various vestibular disorders. At a specialized tertiary center for vertigo and dizziness, patients underwent a systematic and complete neurological, neuroophthalmological, neurootological and neuroorthoptic examination and the following laboratory examinations: video head-impulse test, caloric testing, cervical and ocular vestibular evoked myogenic potentials, and auditory evoked brainstem potentials. The diagnostic criteria were based on the current criteria of the Bárány Society for vestibular migraine [9], benign paroxysmal positional vertigo [10], Menière’s disease [11], vestibular paroxysmia [12], bilateral vestibulopathy [13], and persistent postural-perceptural dizziness (PPPD)/functional dizziness [14]. Consecutive patients with various vestibular disorders were asked about their susceptibility to motion sickness on a standardized questionnaire [“Do you suffer from motion sickness (for instance, nausea while travelling by car, bus, train, ship, or riding on a carousel or looping?”)].

In a study published previously, a control group of 3517 healthy individuals had a prevalence of 13.4% [15]. Those patients < 30 years of age had the highest prevalence (50.2%), and those 80+, the lowest (12%). Women showed a relatively higher prevalence than men (37.5 vs. 27.9%).

In this sample of 785 consecutive patients (mean age 62.9, 46.0% females) presenting with vertigo or dizziness, 31.1% reported motion sickness; because of missing data only 749 were included in the current study for further analysis. Significant differences were observed among the following disease entities (listed in the order of decreasing prevalence of motion sickness; for details see Table 1 with the statistical analyses): 56.9% in vestibular migraine, 48.0% in benign paroxysmal positional vertigo, 37.5% in orthostatic dizziness, 35.1% in Menière’s disease, 32.7% in functional dizziness, 32.0% in unilateral vestibulopathy, 30.8% in vestibular paroxysmia, 25.5% in central dizziness, and 12.4% in patients with bilateral vestibulopathy. In the latter, however, a lower prevalence had been expected because of the functional vestibular loss. Evidently the loss was incomplete, for sufficient vestibular function remained to elicit more motion sickness than anticipated. In another study, patients with bilateral vestibulopathy had reduced motion sickness susceptibility, but were also slightly sensitive to experimental vestibular stimulations [16].

Table 1 Prevalence of motion sickness (yes vs. no) in various age groups, males and females, and various vestibular diseases as well as a healthy control group of 3517 individuals
Full size table

From this prospective epidemiological study, we conclude that motion sickness is a relevant comorbidity of most vestibular disorders. This is particularly true for patients who have recurrent attacks of vertigo, which is the case in benign paroxysmal positional vertigo (almost 50%), Menière’s disease, and vestibular migraine, and in particular for all younger individuals with these diseases. Therefore, doctors should specifically ask whether their patients have experienced this frequently accompanying condition when discussing treatment options (for an overview see [5]). The susceptibility to fear of heights is similarly heightened in vestibular syndromes due to an increased comorbidity of anxiety disorders, such as in vestibular migraine, vestibular paroxysmia, Menière’s disease, and functional dizziness [17].