Virtual reality and musculoskeletal pain: manipulating sensory cues to improve motor performance during walking

Musculoskeletal pain (MSP) is the most expensive nonmalignant health problem and the most common reason for activity limitation. Treatment approaches to improve movement without aggravating pain are urgently needed. Virtual reality (VR) can decrease acute pain, as well as influence movement speed. It is not clear whether VR can improve movement speed in individuals with MSP without aggravating pain. This study investigated the extent to which different audio and optic flow cues in a VR environment influenced walking speed in people with and without MSP. A total of 36 subjects participated, 19 with MSP and 17 controls. All walked on a motorized self-paced treadmill interfaced with a three-dimensional virtual walkway. The audio tempo was scaled (75%, 100%, and 125%) from baseline cadence, and optic flow was either absent, or scaled to 50% or 100% of preferred walking speed. Gait speed was measured during each condition, and pain was measured before and after the experiment. Repeated measures analysis of variance showed that audio tempo above baseline cadence significantly increased walking speed in both groups, F(3, 99) = 10.41, p < 0.001. Walking speed increases of more than 25% occurred in both groups in the 125% audio tempo condition, without any significant increase in pain. There was also a trend toward increased walking speeds with the use of optic flow, but the results in this study did not achieve significance at the p < 0.05 level, F(2, 66) = 2.01, p = 0.14. Further research is needed to establish the generalizability of increasing movement speed across different physical performance tasks in VR.