The role of the visual environment on characteristics of over-ground locomotion in natural and virtual environments

Recent studies have suggested fundamental differences in the way that visual information is processed in virtual environments when compared to natural environments. To better understand these differences, we asked 20 young adults to walk in a real hallway featuring a mobile wall, which allowed three hallway width conditions: narrow (1.14 m), medium (1.31 m) and wide (1.48 m). A separate group of 21 young adults walked in a virtual hallway that closely replicated the real hallway. We were interested in determining (1) whether gait parameters and their variability would be similar between the natural and virtual environments, (2) whether visual information about the width of the hallway would affect gait performance in the two environments, and (3) whether the influence of hallway width would be similar in both environments. We hypothesized that because visual processing is fundamentally different in natural and virtual environments, spatiotemporal gait parameters would also be different in the two environments. Further, we hypothesized that gait and gait variability would be differentially affected by the manipulation of hallway width in the natural and virtual environments. Results indicated participants in the VR environment walked with decreased cadence, spent more time with both feet on the ground, and walked with more variability than participants in the natural environment. Further, several subtle but important differences were found regarding the effect of hallway width on gait in the two environments. In particular, the width of the hallway differentially affected cadence and normalized gait velocity between the real world and VR. These fundamental differences indicate more cautious gait in VR and could have significant implications when we consider how and when we use VR for rehabilitation, training and assessment.