Développement et validation d’un système du simulation de la proprioception de la marche pour créer un sentiment d’incarnation en réalité virtuelle

Abstract

Besides vehicles and animals, human locomotion remains the primary mode to navigation through our environment and became a major factor to determine the state of health and human autonomy in daily life. Especially in the field of rehabilitation where factors as the ideal gait speed to navigate through our environment, a recommendation about daily number of steps as well as human locomotion as a tool to maintain and improve health are of importance. Moreover, engagement, personalized modifications, behavior modification, improving rate of retention and motor learning skills are non-negligible arguments in favour of the use of virtual reality and embodiment in the field of rehabilitation. Embodiment refers to the subjective sensations of ownership and control over an avatar based on sensorial congruence between real actions and intentions and the perceived results. Therefore, both locomotion and embodiment have great potentials for rehabilitation, especially when combining them. Nevertheless, lack of mobility and space are important limitations in terms of natural navigation through any environment (real or virtual), as those can affect movement patterns and intention and can limit the user to establish embodiment hence, depriving the individual of any advantages of virtual reality and locomotion. However, muscle vibration allows us to mimic gait sensorial afferences producing any voluntary muscle commands pre-recorded. All of the above-mentioned aspects justified our objectives : to determine if the addition of lowerlimb muscle-vibrations with gait like patterns to a walking visual self-avatar can improve the perception of walking in healthy standing individuals, and to compare the effects of the complexity of the vibration patterns and of their synchronicity on the sense of embodiment and perception of walking. To do this, five conditions included four with gait-like patterns of vibration were assessed. All conditions were evaluated with questionnaires, two alternatives forced choice and the center of pressure. Similar to previous literature results on visuo-tactile stimulations the subjective results showed positive effects of adding proprioceptive stimulation on the embodiment and the walking perception with no significant influence of the vibration pattern. Whereas anteroposterior oscillations of the center of pressure seems to be related to realness of gait-like patterns of vibration and synchronicity between sensorial stimulations. Moreover, the oscillation frequency of the center of pressure corresponds to the avatar’s walk pace. We conclude that the more synchronized and realistic the sensorial stimulations are, the stronger the embodiment, walking perception, and the motor response to stimuli will be.

Date	6 Oct 2020
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	David Labbé (Supervisor) & Cyril Duclos (Co-supervisor)