Does an outdoor virtual environment projected in a head-mounted display affect balance in healthy young adults?

Background: Virtual reality head-mounted display (VR-HMD) is increasingly used for balance evaluation and rehabilitation. However, more studies must be conducted on virtual environments (VE) effects. This study aimed to assess the impact of an outdoor VE projected in a high-quality VR-HMD and of the VR-HMD mass on postural stability, postural control and leaning.Methods: This study involved ten healthy young men who performed five 30-s stabilometric trials. Four experimental conditions were randomly performed: eyes open (EO) or eyes closed (EC), with (VR) or without (No VR) VR-HMD. Postural stability (antero-posterior (AP) and medio-lateral (ML) ranges of the center of pressure (CoP), 90% confidence ellipse area), postural control (CoP velocity (global, AP and ML)) and standard deviation of the CoP mean position), and postural leaning (AP/ML CoP mean position) were assessed. The comparisons between EO VR and EO No VR were used to analyze the VE effects and comparisons between EC VR and EC No VR for the VR-HMD mass effects.Results: Spatiotemporal parameters that characterised postural stability and postural control, except ML velocity (p > 0.05), were significantly influenced by the simulated VE with higher values in EO VR than EO No VR (p < 0.05), but not by the VR-HMD mass. The mean position of the CoP showed no significant differences between conditions.Significance: Postural stability and postural control modification due to the VE used in this study revealed that this VE could be interesting for VR-HMD rehabilitation and assessment. VR-HMD is not a factor to be considered for stabilometric analysis.