Does the Management of Visual and Audible Motion Information during an Immersive Virtual Reality Timed Up and Go Test Impact Locomotor Performance in the Elderly?

Abstract

<b><i>Background/Aims:</i></b> Falling among the elderly is a major public health issue, especially with the advancing age of the baby boomers. The fall risk assessment tests for many lack a context that would bring them closer to everyday life. Thus, immersive virtual reality, which makes it possible to simulate everyday situations, could make it possible to strengthen the quality of the assessment of the risk of falls. However, it is necessary to understand how the use of a virtual reality device influences the motor control of elderly participants. If vestibular physiotherapists use VR to virtualize their tools, what impact would a visual simulation of movement have on motor control in a locomotor task, if this simulation were plausible? <b><i>Methods:</i></b> Sixty-two elders (70.8 ± 6.7 years old) completed a Timed Up and Go task under 3 conditions: real, virtual reality, and virtual reality with visual and sound movement information. The virtual reality task takes place in a train either stationary at a station or in uniform linear motion. The time and number of steps were recorded using video, and comparisons between conditions were made using Friedman’s test. <b><i>Results:</i></b> The results show a significant increase in the time and number of steps in “virtual reality” condition compared to the “real” condition. They do not show significant differences between the 2 virtual conditions. <b><i>Conclusion:</i></b> The use of a running virtual train to provide plausible movement is particularly distinguished from vestibular physiotherapy applications with first a fixed visual support partially obscuring the optical flow. This visual aid coupled with the attention dedicated to the task inhibits the effect of the moving environment on locomotion. However, the visual optical flow will potentially have an effect in people with fear of falling. Virtual reality shows great potential for the simulation of realistic environments for the assessment of the risk of falls and opens up avenues for the development of tests.

Effects of using immersive virtual reality on time and steps during a locomotor task in young adults

“…Time and number of steps indeed increased whether it was a simple task such as Go and Return phases, or a more complex task such as Turn-Around and Sit-Down. These results were once again comparable with the ones measured with an elderly population [ 18 ].…”

“…In addition, it has been shown that dynamic postural control in adults can be affected by IVR compared to a real situation; increases center of pressure displacement and increases in motor response time have been recorded [ 15 , 16 ]. These results were consistent with two studies conducted by our research team, showing that an IVR effect was measured on elderly with a significant increase in time and number of steps parameters when performing a "Timed Up and Go" (TUG) locomotor task [ 17 , 18 ].…”

“…In details, there were two strategies to perform the Turn-Around: the pivot strategy consisted of transferring the body weight to the stance foot to rotate the trunk at 180° and to redirect the swing foot left behind towards the return phase, that required two weight transfers from one foot to the other one. On the other hand, the multiple steps strategy consisted of performing this same 180° body rotation by using several steps, at least three [ 18 ]. In this study, young adults resorted to these two strategies whereas in our previous studies, elderly always needed multiple steps.…”

“…For instance, increasing the number of steps reflected a safer strategy adopted, witnessing a decrease in step length. Finally, the placement of the camera constrained by the space and placed on the side, slightly set back from the chair to see the back getting off the backrest and to see the participant turning around three meters away [ 18 ], only allowed to measure time and number of steps reliably and accurately.…”

“…Moving train consisted in including a partial linear optical flow in the environment, since optic flow could influence balance and gait when moving [ 20 ]. Our study conducted with elderly showed that optical flow did not further modify motor control in IVR probably due to the characteristics of the locomotor task: locomotion distance too short and presence of a stable visual support [ 18 ].…”