Vection Measured During the 2023 Military Health Service Research Symposium Using a Virtual Reality Headset

Vection, a stationary individual's illusion of self-motion, is a form of spatial disorientation (SD) typically provoked visually. In aviation, SD is a failure to correctly sense one's position, motion, and/or attitude in relation to the earth's surface and its gravitational vertical. The Virtual Reality Vection System (VRVS) induces vection with visual virtual reality (VR) technology. During MHSRS 2023, USAARL demonstrated the VRVS at its Command Booth, which included an approved, exempt protocol to conduct a vection experiment on site. This exploratory study is reported here. The Vive Pro Eye VR headset presented the computer-controlled vection stimuli. Each trial included 2 45-second frames of moving black dots separated by a 15-second blank field. Frame 1 presented 250 randomly spaced dots moving uniformly to the right at 40°/second, illustrating the 100% vection perception. Frame 2 also presented 250 dots moving at 40°/second, but the number of uniformly moving dots was randomly selected from the set {0, 50, 100, 150, 200, 250} while the complement number of dots moved randomly. Data collected were vection duration and magnitude experienced during Frame 2 relative to the 100% Frame 1 vection percept. The subject's button press (BP) and linear potentiometer (LP) settings registered the vection duration and magnitude, respectively. Average BP and LP values were systematically dependent on the number of uniformly moving dots, increasing from 0 to 50 and then to 100 dots, then remaining relatively constant to 200 dots, then further increased with 250 dots, thus demonstrating a systematic psychophysical dependence of vection on quantifiable stimulus motion characteristics. The VRVS successfully used consumer-grade VR technology to execute a quantitative psychophysical pilot study of vection under the uncontrolled conditions of the MHSRS Exhibit Hall. Virtual reality technology can be expected to play an increasing role in supporting research designed for computer-controlled studies at remote sites.