Motion sickness

International classification of vestibular disorders (ICVD): motion sickness diagnostic criteria[1]Cha YH, Golding JF, Keshavarz B, et al. Motion sickness diagnostic criteria: consensus document of the Classification Committee of the Bárány Society. J Vestib Res. 2021;31(5):327-44. https://content.iospress.com/articles/journal-of-vestibular-research/ves200005 http://www.ncbi.nlm.nih.gov/pubmed/33646187?tool=bestpractice.com

Motion sickness and visually induced motion sickness (VIMS)

Motion sickness and VIMS are normal physiological responses that can occur in most people. Motion sickness is diagnosed when the sickness inducing stimulus is physical motion of the person; VIMS is diagnosed when the stimulus is visual motion. An acute episode of motion sickness/VIMS is sickness induced by physical motion/visual motion that meets the following four criteria:

• Physical motion of the person or visual motion elicits signs or symptoms in at least one of the following categories, experienced at greater-than-minimal severity:

  • Nausea and/or gastrointestinal disturbance

  • Thermoregulatory disruption

  • Alterations in arousal

  • Dizziness and/or vertigo

  • Headache and/or ocular strain.

• Signs or symptoms appear during motion and build as exposure is prolonged

• Signs or symptoms eventually stop after cessation of motion

• Signs or symptoms are not better accounted for by another disease or disorder.

Motion sickness disorder (MSD) and visually induced motion sickness disorder (VIMSD)

MSD is diagnosed when the sickness inducing stimulus is physical motion; VIMSD is diagnosed when the stimulus is visual motion. MSD or VIMSD is diagnosed when the following five criteria are met:

• At least five episodes of motion sickness/VIMS triggered by the same or similar motion stimuli

• Signs or symptoms are reliably triggered by the same or similar motion stimuli

• Sign or symptom severity does not significantly decrease after repeated exposure to the same or similar motion stimuli

• Signs or symptoms lead to one or more of the following behavioural or emotional responses:

  • Activity modification to reduce sickness signs/symptom

  • Avoidance of the motion stimulus that triggers sickness

  • Aversive anticipatory emotions prior to exposure to the motion stimulus.

• Signs or symptoms are not better accounted for by another disease or disorder.

Any combination of motion sickness, MSD, VIMS, and VIMSD can co-occur. The intensity of symptoms in response to either physical motion or visual motion stimuli can vary greatly and may fluctuate in an individual due to factors like ageing, adaptation, or the presence of other medical conditions. For acute episodes of motion sickness or VIMS, symptom severity can be worsened by conditions like ocular motility disorders, visual-vestibular disorders, or vestibular disorders such as vestibular migraine, vestibular neuritis, or persistent postural perceptual dizziness. In such cases, both a diagnosis of motion sickness or VIMS and the underlying disorder should be made.