Can We Estimate Motion Sickness Severity in Car Passengers Based on Individual Head Dynamics?

ObjectiveThis study investigates the relationship between motion sickness and body movements experienced by car passengers during non-driving related activities.BackgroundThe theory linking motion sickness to postural instability is well-documented in static environments. However, evidence supporting this theory in dynamic environments, such as moving vehicles, is still lacking.MethodUsing an experimental approach replicating a naturalistic 15-min car ride, 56 participants were equipped with an in-ear sensor to measure the linear accelerations of the head. Participants reported their motion sickness severity at 3-min intervals during the experiment and once more post experimentation. Additionally, the UniPG numerical model was used to estimate motion sickness severity.ResultsThe study identified significant relationships between specific head movement patterns and motion sickness severity, even though the overall symptoms reported were mild. Nonlinear interactions were identified between the standard deviation (<i>p</i> = .032) and the skewness (<i>p</i> = .028) of longitudinal head acceleration, as well as for the skewness (<i>p</i> = .004) and kurtosis (<i>p</i> = .008) of lateral head acceleration. Predictions from the UniPG model correlated with subjective ratings for 67% of participants with some motion sickness symptoms.ConclusionHighly variable longitudinal movements appear more tolerable when lateral movements remain symmetric; however, when both variability and asymmetry in head movements are present together in a specific pattern, they may exacerbate motion sickness symptoms.ApplicationIncorporating motion sickness prediction models in vehicles, based on the measurement of head movements, might improve detection of the escalation of symptoms in car passengers.