Evaluating the Effects of Multiple Environmental Risk Factors on Older Adults’ Walking Safety: An Exploratory Virtual Reality Experiment

With advancing age, declines in cognitive and physical functions impair older adults’ ability to detect and respond to environmental risks, increasing outdoor fall risk. Outdoor falls are more strongly influenced by environmental than individual factors, highlighting the need to examine obstacle-related risks. Building on the Assessment of the Local Outdoor Environment for Falling Over (ALOEF), we conducted field observations at four types of high-frequency activity sites in Shenzhen to identify common outdoor obstacles and developed a multidimensional classification framework for static and dynamic obstacles. Guided by these observations, we used immersive virtual reality (VR) to develop 11 virtual walking scenarios in Unity on the Apple Vision Pro, embedding real-scale obstacle combination to represent multiple environmental risk factors. Eighteen healthy older adults completed all scenarios, and their walking safety was quantified using the obstacle collision rate. A 3×3 within-subjects design crossing three static obstacle conditions (small, large, and combined) with three dynamic obstacle conditions (none, oncoming, and lateral) revealed a significant interaction between static and dynamic obstacles (p<0.001), indicating that walking safety emerges from the interaction of multiple environmental risk factors rather than from single obstacles.