Sensory conflict compared in microgravity, artificial gravity, motion sickness, and vestibular disorders

Area of Science:

• Neuroscience
• Human Physiology
• Aerospace Medicine

Background:

• Motion sickness and perceptual disturbances are commonly linked to sensory conflict.
• Linear acceleration vectors are critical factors in these phenomena, as observed in microgravity and 1-g conditions.

Purpose of the Study:

• To investigate the role of linear vectors in sensory conflict and motion sickness.
• To introduce and validate a novel measure of linear conflict, the "Stretch Factor".

Main Methods:

• Modeling sensory conflict between vestibular and somatosensory systems.
• Computing the "Stretch Factor" to quantify linear conflict.
• Analyzing head movements in microgravity, periodic motions in 1-g, and locomotion in vestibular patients.

Main Results:

• The Stretch Factor explains motion provocation for head movements in microgravity (fast vs. slow, pitch vs. yaw).
• It resolves discrepancies in provocative frequencies between off-vertical-axis rotation (OVAR) and vertical linear oscillation (VLO).
• Mathematical simulations using the Stretch Factor explain sensory conflict perceptions in vestibular patients.

Conclusions:

• The Stretch Factor is a robust predictor of motion sickness provocation.
• Linear acceleration and its measurement are crucial for understanding sensory conflict.
• This model offers insights into vestibular disorders and motion perception.