Publications

The Rehabilitation Gaming System (RGS) has been designed as a flexible, virtual-reality (VR)-based device for rehabilitation of neurological patients. Recently, training of visuomotor processing with the RGS was shown to effectively improve arm function in acute and chronic stroke patients. It is assumed that the VR-based training protocol related to RGS creates conditions that aid recovery by virtue of the human mirror neuron system. Here, we provide evidence for this assumption by identifying the brain areas involved in controlling the catching of approaching colored balls in the virtual environment of the RGS. We used functional magnetic resonance imaging of 18 right-handed healthy subjects (24 ± 3 years) in both active and imagination conditions. We observed that the imagery of target catching was related to activation of frontal, parietal, temporal, cingulate and cerebellar regions. We interpret these activations in relation to object processing, attention, mirror mechanisms, and motor intention. Active catching followed an anticipatory mode, and resulted in significantly less activity in the motor control areas. Our results provide preliminary support for the hypothesis underlying RGS that this novel neurorehabilitation approach engages human mirror mechanisms that can be employed for visuomotor training.

Background and Purpose-Although there is strong evidence on the beneficial effects of virtual reality (VR)-based rehabilitation, it is not yet well understood how the different aspects of these systems affect recovery. Consequently, we do not exactly know what features of VR neurorehabilitation systems are decisive in conveying their beneficial effects. Methods-To specifically address this issue, we developed 3 different configurations of the same VR-based rehabilitation system, the Rehabilitation Gaming System, using 3 different interface technologies: vision-based tracking, haptics, and a passive exoskeleton. Forty-four patients with chronic stroke were randomly allocated to one of the configurations and used the system for 35 minutes a day for 5 days a week during 4 weeks. Results-Our results revealed significant within-subject improvements at most of the standard clinical evaluation scales for all groups. Specifically we observe that the beneficial effects of VR-based training are modulated by the use/nonuse of compensatory movement strategies and the specific sensorimotor contingencies presented to the user, that is, visual feedback versus combined visual haptic feedback. Conclusions-Our findings suggest that the beneficial effects of VR-based neurorehabilitation systems such as the Rehabilitation Gaming System for the treatment of chronic stroke depend on the specific interface systems used. These results have strong implications for the design of future VR rehabilitation strategies that aim at maximizing functional outcomes and their retention. Clinical Trial Registration-This trial was not registered because it is a small clinical study that evaluates the feasibility of prototype devices. (Stroke. 2012;43:2720-2728.)

In this paper we present ideas that can help to close the gap between virtual reality and embedded interaction, which are usually assumed to be the two extremes of a dimension that describes mixed reality interaction. We present our preliminary ideas on surface interaction with stereoscopic data as well as our work on mobile camera-projector units. While the first line of research tries to increase the degree of the interaction experience in virtual worlds, the second uses the physical properties of the real world to enhance the augmented reality experience. The first idea uses the physical world to constraint the interaction in the virtual world. The second idea embeds virtual information into the physical world by respecting its physical properties.

In this paper we present ideas that can help to close the gap between virtual reality and embedded interaction, which are usually assumed to be the two extremes of a dimension that describes mixed reality interaction. We present our preliminary ideas on surface interaction with stereoscopic data as well as our work on mobile camera-projector units. While the first line of research tries to increase the degree of the interaction experience in virtual worlds, the second uses the physical properties of the real world to enhance the augmented reality experience. The first idea uses the physical world to constraint the interaction in the virtual world. The second idea embeds virtual information into the physical world by respecting its physical properties.