Virtual Reality for Rehabilitation

1. The Effects of Avatars on Presence in Virtual Environments for Persons with Mobility Impairments

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The main question we ask is: How do avatars affect presence specifically for Persons with Mobility Impairments (PMIs)? For example, PMIs’ deficits in the proprioceptive sense could affect their body perception in immersive virtual reality, which could impact presence. To investigate this we replicated the classic virtual pit experiment and included a responsive full body avatar (or lack thereof) as a 3D user interface. We recruited from two different populations: 11 PMIs and another 11 Persons without Mobility Impairments (PNMIs) as a control. Each PNMI was matched to a PMI based on age, weight, height, and prior VE exposure. Results of this study indicate that avatars elicit a higher sense of presence for PMIs than for PNMIs. In addition, results suggest that PMIs are easier to immerse in VEs than PNMIs, which may further motivate the future use of VE technology for PMIs.

Paper: Guo, R., Samaraweera, G., Quarles, J. “The Effects of Avatars on Presence in Virtual Environments for Persons with Mobility Impairments” The 24th International Conference on Artificial Reality and Telexistence (ICAT 2014) and the 19th Eurographics Symposium on Virtual Environments (EGVE 2014), Bremen, Germany, 2014.

2. Presence and Gait of Mobility Impaired Persons in Immersive Virtual Environments

We are investigating if Mobility Impaired (MI) persons and healthy persons have a different experience of presence in a Virtual Environment (VE). The previous research on healthy users showed that physiological responses (e.g., heart rate) could be evoked in VE as a surrogate measure of presence. However, almost all of the previous research studies have been conducted only with healthy persons. Thus, it is not known how MI persons will respond to the VE physiologically, how the VE will affect their gait (i.e. walking patterns), or how their sense of presence may differ. To begin investigating this, we designed a VE that included four avatar conditions and four floors with a range of multimodal feedback to induce a strong sense of presence. Using this VE, we conducted a study with two different populations: 8 MI persons and another 8 healthy persons. The healthy participants were of similar demographics (e.g., age, weight, height) to the MI participants and no participants had cognitive impaurment. This research analyses physiological responses and gait data to compare the two groups of participants and for the first time, aims to evaluate indicators of presence for MI users in a VE.

Paper: Guo, R., Samaraweera, G., Quarles, J. “The Effects of VEs on Mobility Impaired Users: Presence, Gait, and Physiological Response” Proceeding of the 19th ACM Symposium on Virtual Reality Software and Technology (VRST2013), 6-9 October 2013, Nanyang Technological University (NTU), Singapore.

3. Latency and Avatars in Virtual Environments and the Effects on Gait for Persons with Mobility Impairments

Latency and avatars in Virtual Environments have been extensively studied over the years. However, there has been minimal research conducted on the effects of latency and avatars for mobility impaired users. To address this, we have conducted a study involving both healthy and mobility impaired participants with the simple task of walking across a simulated room under various latency and avatar conditions. We investigated the impact of latency and avatars on perceived latency and gait parameters (i.e., walking patterns). The results suggest that mobility impaired persons react to latency and the presence of an avatar differently than healthy users.

Paper: Samaraweera, G., Guo, R. and Quarles, J. “Latency and Avatars in Virtual Environments and the Effects on Gait for Persons with Mobility Impairments” in the proceedings of IEEE Symposium on 3D User Interfaces 2013, 16-17 March, Orlando, FL, USA.

4. Differences in Presence between Healthy Users and Users with Multiple Sclerosis

We are investigating how persons with mobility impairments due to multiple sclerosis (MS) experience the sense of presence in a Virtual Environment (VE). Since the mid 90’s, virtual reality (VR) research has produced a rich knowledge of how design and interaction features of VEs affect presence, however to our knowledge almost all of those research studies have been conducted only with healthy persons. Thus, it is not known how these factors affect the presence of mobility impaired persons. To begin investigating this, we replicated a classic VR experiment that has been replicated many times before, but we ran the study with a different population: 10 persons with mobility impairments caused by MS and another 5 healthy persons of similar demographics (e.g., age) as our MS population. This paper compares how these two groups experience presence and discusses the differences we found in our study.

Paper: Guo, R. and Quarles, J. “Differences in Presence Between Healthy Users and Users with Multiple Sclerosis” in the proceedings of the Perceptual Illusions in Virtual Environments Workshop at IEEE Virtual Reality 2012, Costa Mesa, CA.