Designing informed game-based rehabilitation tasks leveraging advances in virtual reality.

PURPOSE: This paper details a brief history and rationale for the use of virtual reality (VR) technology for clinical research and intervention, and then focuses on game-based VR applications in the area of rehabilitation. An analysis of the match between rehabilitation task requirements and the assets available with VR technology is presented. KEY MESSAGES AND IMPLICATIONS: Low-cost camera-based systems capable of tracking user behavior at sufficient levels for game-based virtual rehabilitation activities are currently available for in-home use. Authoring software is now being developed that aims to provide clinicians with a usable toolkit for leveraging this technology. This will facilitate informed professional input on software design, development and application to ensure safe and effective use in the rehabilitation context. CONCLUSION: The field of rehabilitation generally stands to benefit from the continual advances in VR technology, concomitant system cost reductions and an expanding clinical research literature and knowledge base. Home-based activity within VR systems that are low-cost, easy to deploy and maintain, and meet the requirements for "good" interactive rehabilitation tasks could radically improve users' access to care, adherence to prescribed training and subsequently enhance functional activity in everyday life in clinical populations.

Impossible spaces: maximizing natural walking in virtual environments with self-overlapping architecture.

Walking is only possible within immersive virtual environments that fit inside the boundaries of the user's physical workspace. To reduce the severity of the restrictions imposed by limited physical area, we introduce "impossible spaces," a new design mechanic for virtual environments that wish to maximize the size of the virtual environment that can be explored with natural locomotion. Such environments make use of self-overlapping architectural layouts, effectively compressing comparatively large interior environments into smaller physical areas. We conducted two formal user studies to explore the perception and experience of impossible spaces. In the first experiment, we showed that reasonably small virtual rooms may overlap by as much as 56% before users begin to detect that they are in an impossible space, and that the larger virtual rooms that expanded to maximally fill our available 9.14 m x 9.14 m workspace may overlap by up to 31%. Our results also demonstrate that users perceive distances to objects in adjacent overlapping rooms as if the overall space was uncompressed, even at overlap levels that were overtly noticeable. In our second experiment, we combined several well-known redirection techniques to string together a chain of impossible spaces in an expansive outdoor scene. We then conducted an exploratory analysis of users' verbal feedback during exploration, which indicated that impossible spaces provide an even more powerful illusion when users are naive to the manipulation.

Virtual reality and interactive digital game technology: new tools to address obesity and diabetes.

The convergence of the exponential advances in virtual reality (VR)-enabling technologies with a growing body of clinical research and experience has fueled the evolution of the discipline of clinical VR. This article begins with a brief overview of methods for producing and delivering VR environments that can be accessed by users for a range of clinical health conditions. Interactive digital games and new forms of natural movement-based interface devices are also discussed in the context of the emerging area of exergaming, along with some of the early results from studies of energy expenditure during the use of these systems. While these results suggest that playing currently available active exergames uses significantly more energy than sedentary activities and is equivalent to a brisk walk, these activities do not reach the level of intensity that would match playing the actual sport, nor do they deliver the recommended daily amount of exercise for children. However, these results provide some support for the use of digital exergames using the current state of technology as a complement to, rather than a replacement, for regular exercise. This may change in the future as new advances in novel full-body interaction systems for providing vigorous interaction with digital games are expected to drive the creation of engaging, low-cost interactive game-based applications designed to increase exercise participation in persons at risk for obesity.

Development and evaluation of low cost game-based balance rehabilitation tool using the Microsoft Kinect sensor.

The use of the commercial video games as rehabilitation tools, such as the Nintendo WiiFit, has recently gained much interest in the physical therapy arena. Motion tracking controllers such as the Nintendo Wiimote are not sensitive enough to accurately measure performance in all components of balance. Additionally, users can figure out how to "cheat" inaccurate trackers by performing minimal movement (e.g. wrist twisting a Wiimote instead of a full arm swing). Physical rehabilitation requires accurate and appropriate tracking and feedback of performance. To this end, we are developing applications that leverage recent advances in commercial video game technology to provide full-body control of animated virtual characters. A key component of our approach is the use of newly available low cost depth sensing camera technology that provides markerless full-body tracking on a conventional PC. The aim of this research was to develop and assess an interactive game-based rehabilitation tool for balance training of adults with neurological injury.

Evaluation of the cognitive effects of travel technique in complex real and virtual environments.

We report a series of experiments conducted to investigate the effects of travel technique on information gathering and cognition in complex virtual environments. In the first experiment, participants completed a non-branching multilevel 3D maze at their own pace using either real walking or one of two virtual travel techniques. In the second experiment, we constructed a real-world maze with branching pathways and modeled an identical virtual environment. Participants explored either the real or virtual maze for a predetermined amount of time using real walking or a virtual travel technique. Our results across experiments suggest that for complex environments requiring a large number of turns, virtual travel is an acceptable substitute for real walking if the goal of the application involves learning or reasoning based on information presented in the virtual world. However, for applications that require fast, efficient navigation or travel that closely resembles real-world behavior, real walking has advantages over common joystick-based virtual travel techniques.

Emotional and performance attributes of a VR game: a study of children.

In this paper we present the results of a study to determine the effect and efficacy of a Virtual Reality game designed to elicit movements of the upper extremity. The study is part of an on-going research effort to explore the use of Virtual Reality as a means of improving the effectiveness of therapy for children with motor impairments. The current study addresses the following questions: 1. Does a VR game requiring repetitive motion sufficiently engage a child? 2. Are there detrimental physiological or sensory side-effects when a child uses an HMD-based VR? 3. Are the movements produced by a child while playing a VR game comparable to movements produced when carrying out a similar task in the real-world? Based on study results, the enjoyment level for the game was high. ANOVA performed on the results for physical well-being pre- and post-VR showed no overall ill-effects as perceived by the children. Playing the game did not effect proprioception based on pre- and post-VR test scores. Motion data show similar, but not identical, overall movement profiles for similar tasks performed in the real and virtual world. Motor learning occurs in both environments, as measured by time to complete a game cycle.