Influence of virtual reality on postural stability during movements of quiet stance

Introduction: Balance problems during virtual reality (VR) have been mentioned in the literature but seldom investigated despite the increased use of VR systems as a training or rehabilitation tool. We examined the influence of VR on body sway tinder different stance conditions. Methods: Seventeen young subjects performed four tasks (standing with feet close together or tandem stance on firm and foam surfaces for 60s) under three visual conditions: eyes open without VR, eyes closed, or while viewing a virtual reality scene which moved with body movements. Angular velocity transducers mounted on the shoulder provided measures of body sway in the roll and pitch plane. Results: VR caused increased pitch and roll angles and angular velocities compared to EO. The effects of VR were, for the most part, indistinguishable from eyes closed conditions. Use of a foam surface increased sway compared to a firm surface undereyes closed and VR conditions. Conclusion: During the movements of quiet stance, VR causes an increase in postural sway in amplitude similar to that caused by closing the eyes. This increased sway was present irrespective of stance surface, but was greatest on foam. (C) 2009 Elsevier Ireland Ltd. All rights reserved.