Amplitude and Temporal Dynamics of Motion Sickness

Area of Science:

• Human physiology
• Biomechanics
• Human-computer interaction

Background:

• The relationship between motion amplitude and motion sickness accumulation over time is not well understood.
• Individual differences in motion sickness susceptibility are significant.

Purpose of the Study:

• To investigate the relationship between motion amplitude and motion sickness severity at individual and group levels.
• To analyze the temporal evolution of motion sickness using variations of the Oman model.
• To assess the impact of individual sickness dynamics on the accuracy of sickness forecasting models.

Main Methods:

• Seventeen participants were exposed to four different motion amplitudes (1, 1.5, 2, 2.5 ms⁻²).
• A multi-phase protocol including motion exposure, rest, and hypersensitivity testing was used.
• Three variations of the Oman model, including a modified power-law scaling, were applied to analyze sickness evolution.

Main Results:

• Motion sickness severity (MISC) demonstrated a linear increase with acceleration amplitude at both individual and group levels.
• The slow and fast time constants of motion sickness were independent of motion amplitude but showed substantial inter-individual variability.
• An adapted Oman model with a power-law exponent of 0.4 provided a superior fit to the data compared to the original exponent of 2.
• Forecasting accuracy of the Oman model was significantly influenced by individual sickness dynamics (divergent vs. convergent).

Conclusions:

• Motion sickness severity is directly proportional to motion amplitude.
• Individual variability in sickness time constants is a key factor in motion sickness progression.
• The modified Oman model offers improved prediction of motion sickness.
• Findings have implications for participant screening and real-time adaptation of automated vehicle systems.