Exploring the Agency in VR Co-embodiment Rehabilitation Based on First- and Third-person Perspectives

Upper limb motor dysfunction in patients with stroke could limit their daily activities, and virtual reality (VR) has been proven to provide interactive training for enhancing rehabilitation. However, many studies presume independent tasks, which can be challenging for patients with limited motor control. The virtual co-embodiment method in VR has the potential to allow patients and therapists to share the same avatar to collaboratively perform rehabilitation tasks. Specifically, this method could impact the patients’ agency (feeling of controlling virtual avatars) and enable therapists to compensate for patients’ limited mobility. Prior research has shown that the avatar’s first or third-person perspective can affect the agency, but studies on co-embodiment have not yet examined how these two users’ perspectives influence their experiences. Our study investigates how first or third-person perspectives for both patients and therapists moderate the agency during VR co-embodiment. We found that differences in participants’ roles and objectives influence participants’ perspective preferences during VR co-embodiment. These findings inform the design of multi-user collaboration to enhance patients’ motor recovery in VR rehabilitation.