Quantitative measures of the visually evoked sensation of body movement in space (Vection) using Electrovestibulography (EVestG)

Vection is defined as an illusory self-motion sensation induced in stationary observers that can be experienced in a real/virtual world. Vection, as a result of immersion in virtual reality (VR) environments, can subsequently lead to a sense of inability to maintain postural control and cause cybersickness symptoms. The multisensory integration of visual and vestibular (balance) information plays a vital role in vection. The etiology of vection perception, as well as, the vestibular response change while experiencing vection is poorly understood. This study explores vestibular response change following vection in 20 individuals (10 females, 26.45 ± 4.40 (SD) years). Vection was induced in participants using an immersive VR roller-coaster. The vestibular response was measured simultaneously using a noninvasive method called Electrovestibulography (EVestG). The detected field potentials and the time intervals between the field potentials were extracted from the recorded EVestG signals corresponding to four segments of the VR roller-coaster trajectory namely Stationary, Up movement, Down movement, and slopes and turns (Mix). The results show that the Stationary segment is significantly different (P < 0.05) from other dynamic segments when the average field potential of the right and left ear are subtracted. Furthermore, the Stationary segment shows longer time intervals between field potentials compared to those of the other segments in the right ear. These observations suggest that the combined effect of the visually induced sensation of self-motion together with a concurrent/co-occurring stress/anxiety factor can affect the vestibular activity in an excitatory way. Increased excitatory vestibular activity implies increased feeling of imbalance and more likelihood of experiencing cybersickness by the participants.