The Effect of Feedback About Self When Stepping over Obstacles in Natural and Virtual Environments

Obstacle negotiation during locomotion depends on the integration of exteroceptive information about the environment, proprioceptive signals from the body, and exproprioceptive visual feedback about the limbs. This study examined how removing visual limb information and introducing VR-specific sensory uncertainty affect overground obstacle-crossing behavior. Participants walked under three conditions: natural environment with full vision, natural environment with lower-limb occlusion, and immersive VR without a lower-limb representation. Removing limb vision in the real world selectively increased toe clearance while leaving baseline gait unchanged, demonstrating the role of exproprioceptive feedback in fine-tuning foot trajectory. VR amplified these adaptations, yielding slower speeds, wider bases of support, and even greater clearance margins, reflecting compounded uncertainty from altered exteroceptive cues. Yet obstacle location effects were consistent across environments, suggesting preserved underlying control and the potential for a scaling relationship between VR and real-world performance. Findings highlight key design considerations for VR-based gait assessment and rehabilitation.