To see or not to see: Does foot visualization in immersive virtual reality influence gait parameters of youths with neuromotor impairments when performing walking-related activities?

BACKGROUND: Immersive virtual reality (VR) experienced through a head-mounted display (HMD) offers the possibility to practice real-world situations in a safe and motivating way in pediatric neurorehabilitation. As the HMD blocks the view of the physical world, patients lack visual feedback of their body parts. Foot visualization in the virtual environment could inform patients about their feet's position during walking-related activities. RESEARCH QUESTION: How does foot visualization affect spatial gait parameters of youths with neuromotor gait impairments during everyday walking tasks with an immersive VR-HMD? METHODS: In this cross-sectional study, 15 youths with neuromotor gait impairments (mean age 12.3 years) performed four walking-related tasks wearing the VR-HMD Meta Quest 2. Walking through the virtual environment, they had to place their feet as accurately as possible on bollards, step over a plank, balance over a beam, and cross a gap. We used a Vicon motion capture system to assess spatial gait parameters when the participants could not see their feet and when a real-time virtual model of their feet was integrated into the virtual environment. RESULTS: In the bollard task, foot visualization had a large positive effect (Hedges' g = 0.82) on the foot placement accuracy, with a reduction in deviation from the bollard center from 12.1 cm (IQR: 16 cm) to 6.5 cm (IQR: 5.1 cm) (p < 0.001). Further, the maximum step height of the leading foot when overstepping the plank decreased by 2.9 cm (g = 0.4, p = 0.05). Foot visualization did not influence the spatial gait parameters when balancing over a beam or crossing a gap. SIGNIFICANCE: Pediatric patients who practice walking-related activities with an immersive VR-HMD can benefit from foot visualization, as it increases foot placement accuracy for certain tasks. However, technical solutions have to become simpler for the clinical implementation of foot visualization.