Postural Stability During Illusory Self-Motion - Interactions of Vision and Touch

Abstract

The role of vision in stabilizing balance has been studied exhaustively. Other studies have shown that non-supportive light touch of the fingertip with a surface also can significantly stabilize postural balance. We have studied how vision and cutaneous information jointly affect balance. We used a head-mounted display to simulate a virtual room that rotated about a vertical axis centered with the standing subjects z-axis. Subjects viewing the displays rotational displacement soon experienced self-motion and displacement. We assessed how the moving visual input destabilized posture and how it interacted with touch cues that stabilized posture. A novel result is how balance is influenced by the onset of visual motion and the illusion of self-rotation. We discovered that motion perceptions are coupled with stochastic aspects of balance. Changes in the perception of types of motion - none, environment-, and self-rotation - distinctively influence metrics that encode for the stochasticity of balance and do not influence those that filter the stochasticity out. We reconfirmed the significant effects of touch in stabilizing balance and discovered how it interacts with the visual perception of motion. We also found lingering effects of past motion perception, which keep influencing the stochasticity of balance even when visual motion is long stopped. Our findings provide insights into multisensory interaction effects in postural balance and suggest novel future research directions.