Immersive virtual reality makes possible to perceive and interact in a standardized, reproductible and digital environment, with a wide range of simulated situations possibilities. This study aimed to measure the potential effect of virtual reality on time and number of steps when performing a locomotor task, in a young adult’s population. Sixty young adults (32W, 28M, mean age 21.55 ± 1.32), who had their first immersive virtual reality experience, performed a locomotor task based on "Timed Up and Go" (TUG) task in real, in virtual reality in a stopped train and in virtual reality in a moving train. Time and number of steps variables representing primary locomotion indicators were measured and compared between each condition. Results showed significant increases in time and number of steps in the two virtual reality conditions compared to real but not between the two virtual reality conditions. There was an effect of virtual reality in young adults when performing the locomotor task. It means that technological and digital characteristics of the immersive virtual reality experience led to modify motor strategies employed. Adding a plausible visual optic flow did not appear to affect motor control further when the information is negligible and not essential for performing the task.

In recent years, immersive virtual reality technology has emerged in the field of health. Its use could allow the assessment of the motor behavior of individuals in adaptable and reproducible immersive environments, simulating real situations. This study aimed to assess the effect of an immersive scenario on functional mobility during a simple locomotor task according to age. Sixty young adults and 60 older volunteers, who were autonomous and without cognitive and neurological impairment participated. A locomotor task based on the “Timed Up and Go” task was performed in real and virtual conditions. A functional mobility score was calculated by combining the time and the number of steps used and compared between young and older people. Results showed that correlations between time and the number of steps were the same in VR and real conditions, but the locomotor performance decreased significantly in VR for both populations. Additionally, older people exhibited a more reduced locomotor performance in a virtual environment than young adults, thereby their functional mobility score decreased more to complete the task, reflecting the adoption of a more secure locomotion strategy often related to the fear of falling, with an increase in time and number of steps to support balance. The major difference between reality and VR is the visual immersion with an HMD, and visual information is more important in the sensory integration of older people. Therefore, the reduction in visual field and lack of visual exproprioceptive information about the body segments in the virtual environment could explain these results. Finally, the effect of immersion in a virtual scenario on mobility exists for both populations but is accentuated by the aging process and is therefore age dependent.

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La chute est la première cause d'accident chez les personnes âgées. Chaque année, elle concerne 1 personne sur 4 chez les plus de 65 ans. Le risque de chute est multifactoriel : ses causes peuvent notamment être motrices, attentionnelles ou cognitives. Afin de mieux caractériser, comprendre et prédire ce risque de chute, nous proposons aux praticiens une solution technologique fondée sur la réalité virtuelle, permettant de collecter et d'identifier différents indicateurs du risque de chute. Cette solution simple d'utilisation automatise le protocole expérimental et la collecte d'indicateurs, assure la reproductibilité des conditions expérimentales, et immerge le patient dans un environnement réaliste et des situations de la vie courante.Notre outil, compatible avec des dispositifs de réalité virtuelle grand public, utilise un total de 6 capteurs portés par le patient pour permettre une capture cinématique du corps complet, restitué en temps réel au patient sous la forme d'un avatar virtuel. Ces données cinématiques, rejouable pour le praticien, permettent d'alimenter un processus d'apprentissage numérique.L'expérimentation place le patient dans 6 situations de test, introduisant progressivement différentes tâches et obstacles afin de tester et de collecter des indicateurs sur ses capacités motrices, attentionnelles et cognitives, permettant des comparaisons interpatient et inter-condition.