Relationship Between Eye Movements and Individual Differences in Motion Sickness Susceptibility While Viewing Stereoscopic Movies Under Controlled Consciousness

摘要

In our previous study, we found it is possible to affect subjective feelings of visually induced motion sickness (VIMS) by controlling visually evoked postural responses (VEPRs) by changing conditions of consciousness of body sway. Thus, in this study, we verified the relationship between eye movements, body sway, and the susceptibility to motion sickness. Controlling consciousness of body sway while participants viewed stereoscopic movies revealed the involvement of three related theories for VIMS or motion sickness: sensory conflict theory, postural instability theory, and eye movement theory. Participants filled in a motion sickness susceptibility questionnaire short form (MSSQ-short). Thereafter, in the demonstration experiment, participants watched a three-dimensional movie consisting of several colored balls that moved sinusoidally at 0.25 Hz in the horizontal direction for 3 min after pre-instruction. Pre-instructions included "uncontrolled consciousness", "keep a static, upright posture", and "sway body in the same/opposite direction". This study recorded both body sway and electrooculography (EOG) data. Recorded EOG data were converted to eye movement velocity. The main result showed that susceptible participants exhibited a decreased frequency of optokinetic nystagmus (OKN) under conditions prone to the occurrence of OKN from correlated analysis for eye movements. Hence, we concluded that sensory conflict induced by decreases in the frequency of OKN is the primary cause of VIMS as OKN has a role in postural maintenance. This is a different hypothesis than the traditional eye movement theory.