CAVE2 Comparison of 1st/3rd User Perspectives in Virtual Motor Rehabilitation Tasks

Stroke is the leading cause of severe longstanding impairments in the US. Besides facing economic issues, stroke survivors are required to attend to rehabilitation therapies to deal with physical and cognitive disabilities that reduce their quality of life. In this context, virtual rehabilitation appears as an additional support to traditional treatments by taking advantage of virtual reality. However, researchers do not agree on which of virtual reality aspects are more relevant for specific therapies. One of those aspects is the user perspective; how a patient see a virtual environment but we do not know which is more beneficial. Rehabilitation applications mostly use first-person perspective or third-person perspective but rarely offer both; thus, a comparison between them is difficult to achieve. We performed a user study (N=30) in the CAVE2 environment with RehabJim, a virtual rehabilitation game for upper limbs recovery developed at the Electronic Visualization Laboratory (EVL). Our analysis compared the effect of the user perspective, training modes, and two target sizes on user performance, the degree of immersion and body movements. Results suggested an effect of the training mode factor, and a smaller effect of the user perspective on time required to finish a task, hand movements, and movement corrections. User perspective had the main effect on head movements, but subjects felt the same immersion level under both user perspectives.