The feasibility of using virtual reality to induce mobility-related anxiety during turning

The fear of falling, or mobility-related anxiety, profoundly affects gait, but is challenging to study without risk to participants. Purpose: To determine the efficacy of using virtual reality (VR) to manipulate illusions of height and consequently, elevated mobility-related anxiety when turning. Moreover, we examined if mobility-related anxiety effects decline across time in VR environments as participants habituate. Methods: Altogether, 10 healthy participants (five women, mean (standard deviation) age = 28.5 (8.5) years) turned at self-selected and fast speeds on a 2.2m walkway under two simulated environments: (1) ground elevation; and (2) high elevation (15m above ground). Peak turning velocity was recorded using inertial sensors and participants rated their cognitive (i.e., worry) and somatic (i.e., tension) anxiety, confidence, and mental effort. Results: A significant Height x Speed x Trial interaction (p = 0.013) was detected for peak turning velocity. On average, the virtual height illusion decreased peak turning velocity, especially at fast speeds. At low elevation, participants decreased speed across trials, but not significantly (p = 0.381), but at high elevation, they significantly increased speed across trials (p = 0.001). At self-selected speeds, no effects were revealed (all p > 0.188) and only effects for Height were observed for fast speeds (p < 0.001). After turning at high elevation, participants reported greater cognitive (p = 0.008) and somatic anxiety (p = 0.007), reduced confidence (p = 0.021), and greater mental effort (p < 0.001) compared to the low elevation. Conclusion: VR can safely induce mobility-related anxiety during dynamic motor tasks, and habituation effects from repeated exposure should be carefully considered in experimental designs and analysis.