Relationship Between Feeling of Presence and Visually Induced Motion Sickness While Viewing Stereoscopic Movies

Visually evoked postural responses (VEPRs) are postural changes induced by visual information. We focused on the change in VEPRs that better represents a feeling of presence or symptom of visually induced motion sickness (VIMS). We investigated the effect of stereoscopic vision on the change in the degree of feeling and VEPRs by simultaneous measurement of both feeling of presence, VIMS symptom, and body sway when viewing a movie showing a roundtrip sinusoidal motion. For the feeling of presence, significantly positive correlations between the body-sway indexes and visual analog scale value of the presence were observed. However, when the subject watched a two-dimensional movie, the correlations between the subjective and objective evaluation decreased. In contrast, no significantly positive/negative correlation between the body-sway indexes and the simulator sickness questionnaire scores was found. Therefore, performing objective assessments of the degree of subjective symptoms induced by VIMS by measuring body sway is difficult.