Individual motion perception parameters and motion sickness frequency sensitivity in fore-aft motion

Abstract

Previous literature suggests a relationship between individual characteristics of motion perception and the peak frequency of motion sickness sensitivity. Here, we used well-established paradigms to relate motion perception and motion sickness on an individual level. We recruited 23 participants to complete a two-part experiment. In the first part, we determined individual velocity storage time constants from perceived rotation in response to Earth Vertical Axis Rotation (EVAR) and subjective vertical time constants from perceived tilt in response to centrifugation. The cross-over frequency for resolution of the gravito-inertial ambiguity was derived from our data using the Multi Sensory Observer Model (MSOM). In the second part of the experiment, we determined individual motion sickness frequency responses. Participants were exposed to 30-minute sinusoidal fore-aft motions at frequencies of 0.15, 0.2, 0.3, 0.4 and 0.5 Hz, with a peak amplitude of 2 m/s2 in five separate sessions, approximately 1 week apart. Sickness responses were recorded using both the MIsery SCale (MISC) with 30 s intervals, and the Motion Sickness Assessment Questionnaire (MSAQ) at the end of the motion exposure. The average velocity storage and subjective vertical time constants were 17.2 s (STD = 6.8 s) and 9.2 s (STD = 7.17 s). The average cross-over frequency was 0.21 Hz (STD = 0.10 Hz). At the group level, there was no significant effect of frequency on motion sickness. However, considerable individual variability was observed in frequency sensitivities, with some participants being particularly sensitive to the lowest frequencies, whereas others were most sensitive to intermediate or higher frequencies. The frequency of peak sensitivity did not correlate with the velocity storage time constant (r = 0.32, p = 0.26) or the subjective vertical time constant (r = − 0.37, p = 0.29). Our prediction of a significant correlation between cross-over frequency and frequency sensitivity was not confirmed (r = 0.26, p = 0.44). However, we did observe a strong positive correlation between the subjective vertical time constant and general motion sickness sensitivity (r = 0.74, p = 0.0006). We conclude that frequency sensitivity is best considered a property unique to the individual. This has important consequences for existing models of motion sickness, which were fitted to group averaged sensitivities. The correlation between the subjective vertical time constant and motion sickness sensitivity supports the importance of verticality perception during exposure to translational sickness stimuli.

Amplitude and Temporal Dynamics of Motion Sickness

“…This is given by the fact that the severity of sickness in different directions is similar to each other (Donohew and Griffin, 2004 ). However, if a coupling exists between different degrees-of-freedom, such that the resultant stimulus has a complex frequency spectrum, this may cause currently unknown interactions in the conflict signal due to differing frequency sensitivities (Irmak et al, 2021 ). Similarly, with reduced motion predictability (Kuiper et al, 2020 ) compared to our current sinusoidal acceleration stimuli, a greater sickness response is expected.…”

Relating individual motion sickness levels to subjective discomfort ratings

“…As such, administering the MISC is minimally invasive among any other experimental procedures, and it has proven to be a convenient and popular tool to monitor the progression of motion sickness symptoms over time (e.g., Irmak et al. 2020 , 2021 ). Early versions of the MISC were developed to rate sickness experienced on ships (Wertheim et al.…”

“…2005 ; Irmak et al. 2021 ). Violation of this assumption may affect the validity of conclusions that follow from such analyses (Winship and Mare 1984 ).…”

“…The ratings can be given verbally and instantaneously. As such, administering the MISC is minimally invasive among any other experimental procedures, and it has proven to be a convenient and popular tool to monitor the progression of motion sickness symptoms over time (e.g., Irmak et al 2020Irmak et al , 2021. Early versions of the MISC were developed to rate sickness experienced on ships (Wertheim et al 1998), and were based on the notion that although the severity of symptoms varies between individuals, symptoms such as dizziness, hot or cold flushes, headache, stomach awareness, and sweating precede nausea and vomiting.…”

“…General methods exist to deal with this, such as ordinal regression (Scott Long 1997). However, MISC data are typically analysed using linear regression models or other techniques that make the assumption that the data form an interval scale (e.g., Bos et al 2005;Irmak et al 2021). Violation of this assumption may affect the validity of conclusions that follow from such analyses (Winship and Mare 1984).…”