Investigating Techniques to Enhance the Sense of Embodiment in Immersive Virtual Reality

Embodiment is an important aspect of virtual reality because it affects how natural and engaging the experience feels and can influence performance and learning in VR-based applications, including rehabilitation \[McAnally \& Wallis, 2022\]. In VR, embodiment refers to the extent to which a person feels that a virtual body (avatar) is their own and under their control. It is typically described as having three components: sense of agency (feeling that one is causing the avatar's actions), body ownership (feeling that the avatar's body is one's own), and self-location (feeling located where the avatar is) \[Kilteni, Groten, \& Slater, 2012\]. While many VR systems aim to increase embodiment, there is limited evidence on which specific techniques are most effective-especially in people with acquired neurological injuries, in whom central nervous system damage may alter body perception and multisensory integration \[Guy, Normand, Jeunet-Kelway, \& Moreau, 2023\]. This study will compare several VR techniques that may enhance embodiment, including synchronized visual and tactile stimulation, heart-rate-based visual biofeedback, increased possibilities to actively control the avatar, and familiarity with the performed action. Participants will include healthy volunteers and individuals with acquired neurological injuries (spinal cord injury or stroke). Across three study days, participants will complete multiple short VR conditions while wearing physiological sensors, and after each VR condition, participants will complete questionnaires about their VR experience. The goal is to identify which VR techniques most effectively increase embodiment and whether embodiment-related responses differ between healthy participants and clinical groups.