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Traditional methods of movement assessment in clinical rehab are often labor intensive and provide a limited number of outcome variables for tracking recovery. Entry level virtual reality (VR) systems afford new possibilities for systematic assessment and treatment. This paper describes the development of a virtual tabletop environment for the assessment of upper limb function in Traumatic Brain Injury (TBI). The system is designed to present realistic virtual workspaces and to measure performance at both a functional and kinematic level. In addition, we incorporate the use of Tangible User Interfaces (TUIs) as a means of integrating performance with the workspace. Unlike top-end movement analysis systems, the experimental system utilizes readily available computing technologies: mid-range PC, LCD panels, stereo camera, Virtools software, and TUI enabled by Wii Remote, Wii Sensor Bar (Nintendo™) and passive markers. The combination of visionbased marker tracking with a low cost game controller (viz Wii system) provides a stable and accurate means of tracking the TUI on the virtual workspace, and for interactivity within this space. The system provides a compelling sense of realism for the performer and an innovative means of assessing movement capabilities over time.

Deficits in upper limb function are common among patients with Traumatic Brain Injury (TBI). Accordingly, new technologies, such as virtual reality (VR), are being developed to further upper limb rehabilitation. The study described here successfully trialed a table-top VR-based system (called Elements). Two patients with TBI participated in case-studies using a multiple-baseline, AB time-sequence design; the intervention consisted of 12 1-hour sessions. Performance was measured on both system-rated measures and standardized tests of functional skill. Time-sequence plots for each patient were first sight inspected for trends; this was followed by split-middle trend analysis. Participants demonstrated significant improvements in their movement accuracy, efficiency, and bimanual dexterity; and mixed improvement on speed and other measures of movement skill. Taken together, these findings demonstrate that the Elements system facilitated motor learning in both TBI patients. Larger scale clinical trials are now deemed a viable step in further validating the system.

This paper presents a conceptual model for movement rehabilitation of Traumatic Brain Injury (TBI) using virtual environments. This hybrid model integrates principles from ecological systems theory with recent advances in cognitive neuroscience, and supports a multilevel approach to both assessment and treatment. Performance outcomes at any stage of recovery are determined by the interplay of task, individual, and environmental/contextual factors. We argue that any system of rehabilitation should provide enough flexibility for task and context factors to be varied systematically, based on the current neuromotor and biomechanical capabilities of the performer or patient. Thus, in order to understand how treatment modalities are to be designed and implemented, there is a need to understand the function of brain systems that support learning at a given stage of recovery, and the inherent plasticity of the system. We know that virtual reality (VR) systems allow training environments to be presented in a highly automated, reliable, and scalable way. Presentation of these virtual environments (VEs) should permit movement analysis at three fundamental levels of behaviour: (i) neurocognitive bases of performance (we focus in particular on the development and use of internal models for action which support adaptive, on-line control); (ii) movement forms and patterns that describe the patients' movement signature at a given stage of recovery (i.e, kinetic and kinematic markers of movement proficiency), (iii) functional outcomes of the movement. Each level of analysis can also map quite seamlessly to different modes of treatment. At the neurocognitive level, for example, semi-immersive VEs can help retrain internal modeling processes by reinforcing the patients' sense of multimodal space (via augmented feedback), their position within it, and the ability to predict and control actions flexibly (via movement simulation and imagery training). More specifically, we derive four key therapeutic environment concepts (or Elements) presented using VR technologies: Embodiment (simulation and imagery), Spatial Sense (augmenting position sense), Procedural (automaticity and dual-task control), and Participatory (self-initiated action). The use of tangible Manuscript received April 30, 2006.

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