Motion sickness diagnostic criteria: Consensus Document of the Classification Committee of the Bárány Society

We present diagnostic criteria for motion sickness, visually induced motion sickness (VIMS), motion sickness disorder (MSD), and VIMS disorder (VIMSD) to be included in the International Classification of Vestibular Disorders. Motion sickness and VIMS are normal physiological responses that can be elicited in almost all people, but susceptibility and severity can be high enough for the response to be considered a disorder in some cases. This report provides guidelines for evaluating signs and symptoms caused by physical motion or visual motion and for diagnosing an individual as having a response that is severe enough to constitute a disorder. The diagnostic criteria for motion sickness and VIMS include adverse reactions elicited during exposure to physical motion or visual motion leading to observable signs or symptoms of greater than minimal severity in the following domains: nausea and/or gastrointestinal disturbance, thermoregulatory disruption, alterations in arousal, dizziness and/or vertigo, headache and/or ocular strain. These signs and/or symptoms occur during the motion exposure, build as the exposure is prolonged, and eventually stop after the motion ends. Motion sickness disorder and VIMSD are diagnosed when recurrent episodes of motion sickness or VIMS are reliably triggered by the same or similar stimuli, severity does not significantly decrease after repeated exposure, and signs/symptoms lead to activity modification, avoidance behavior, or aversive emotional responses. Motion sickness/MSD and VIMS/VIMSD can occur separately or together. Severity of symptoms in reaction to physical motion or visual motion stimuli varies widely and can change within an individual due to aging, adaptation, and comorbid disorders. We discuss the main methods for measuring motion sickness symptoms, the situations conducive to motion sickness and VIMS, and the individual traits associated with increased susceptibility. These additional considerations will improve diagnosis by fostering accurate measurement and understanding of the situational and personal factors associated with MSD and VIMSD.