Negin Hamzeheinejad, M.Sc.

Abstract: This paper examines the impact of implicit and explicit feedback in Virtual Reality (VR) on performance and user experience during motor rehabilitation. In this work, explicit feedback consists of visual and auditory cues provided by a virtual trainer, compared to traditional feedback provided by a real physiotherapist. Implicit feedback was generated by the walking motion of the virtual trainer accompanying the patient during virtual walks. Here, the potential synchrony of movements between the trainer and trainee is intended to create an implicit visual affordance of motion adaption. We hypothesize that this will stimulate the activation of mirror neurons, thus fostering neuroadaptive processes. We conducted a clinical user study in a rehabilitation center employing a gait robot. We investigated the performance outcome and subjective experience of four resulting VR-supported rehabilitation conditions: with/without explicit feedback, and with/without implicit (synchronous motion) stimulation by a virtual trainer. We further included two baseline conditions reflecting the current NonVR procedure in the rehabilitation center. Our results show that additional feedback generally resulted in better patient performance, objectively assessed by the necessary applied support force of the robot. Additionally, our VR supported rehabilitation procedure improved enjoyment and satisfaction, while no negative impacts could be observed. Implicit feedback and adapted motion synchrony by the virtual trainer led to higher mental demand, giving rise to hopes of increased neural activity and neuroadaptive stimulation.

Abstract: Gait rehabilitation is a necessary process for patients suffering from post-stroke motor impairments. The patients are required to perform repetitive practices using a robot-assisted gait device. Repeated exercises can become extremely frustrating and the patients lose their motivation over time. In my PhD research, I focus on Virtual Reality (VR) as a medium to improve gait rehabilitation in terms of enjoyment, motivation, efficiency, and effectiveness. The objective is to systematically investigate different factors, such as the presence of a trainer, interactivity, gamification, and storytelling in a two-step process. First, by evaluating the applicability of different factors for the clinical use with healthy subjects. Second, by evaluating the effectiveness of the VR simulation with patients with gait deficits, especially stroke patients in collaboration with a country clinic.

Abstract: Gait impairments from neurological injuries require repeated and exhaustive physical exercises for rehabilitation. Prolonged physical training in clinical environments can easily become frustrating and de-motivating for various reasons which in turn risks to decrease efficiency during the healing process. This paper introduces an immersive VR system for gait rehabilitation which targets user experience and increase of motivation while evoking comparable physiological responses needed for successful training effects. The system provides a virtual environment consisting of open fields, forest, mountains, waterfalls, animals, and a beach for inspiring strolls and is able to include a virtual trainer as a companion during the walks. We evaluated the ecological validity of the system with healthy subjects before performing the clinical trial. We assessed the system\u0027s target qualities with a longitudinal study with 45 healthy participants in three consecutive days in comparison to a baseline non-VR condition. The system was able to evoke similar physiological responses. The workload was increased for the VR condition but the system also elicited a higher enjoyment and motivation which was the main goal. The latter benefits slightly decreased over time (as did workload) while they were still higher than in the non-VR condition. The virtual trainer did not show to be beneficial, the corresponding implications are discussed. Overall, the approach shows promising results which renders the system a viable alternative for the given use case while it motivates interesting direction for future work.

Abstract: This paper presents an immersive Virtual Reality (VR) therapy system for gait rehabilitation after neurological impairments, e.g., caused by accidents or strokes: The system targets increase of patients\u0027 motivation to perform the repeated exercise by providing stimulating virtual exercise environments with the final goal to increase therapy efficiency and effectiveness. Instead of simply working out on immobile stationary devices, the system allows them to walk through and explore a stimulating virtual world. Patients are immersed in the virtual environments using a Head-Mounted Display (HMD). Walking patterns are captured by motion sensors attached to the patients\u0027 feet to synchronize locomotion speed between the real and the virtual world. A user-centered design process evaluated usability, user experience, and feasibility to confirm the overall goals of the system before any sensitive clinical trials with impaired patients can start. Overall, the results demonstrated an encouraging user experience and acceptance while it did not induce any unwanted side-effects, e.g., nausea or cyber-sickness.

Abstract: Fortunately, physiotherapy and repetitive movement during exercises allows to regain motor functions lost by neurological injuries, i.e., caused by strokes. Exercising is exhausting and patients’ motivation plays a central role in the effectiveness or such therapies. Unfortunately, dedicated therapy equipment often requires to restrict users or to be setup in lesser attractive environments due to, e.g., building statics. In addition, such systems currently do not exploit the potential of adaptive training stimuli based on movement mimicry. We introduce first results of a VR based gait rehabilitation system: VRGait immerses patients into alternative virtual environments and maps their movements on the therapy device to movements in the virtual worlds (see Figure 1). VRGait’s goals are to strengthen therapy effectiveness (1) by increased motivation from inspiring walking escapes (think beach or mountain scenes) and gamified tasks and (2) by exploiting motor mimicry caused by their controlled virtual avatars or counterparts walking together with them.