HEnRiE – Haptic Environment for Reaching and Grasping Exercise Matja ˇ z Mihelj, Janez Podobnik and Marko Munih Abstract— Task-oriented repetitive movements can improve motor recovery in patients with neurological or orthopaedic lesions. HEnRiE is a robot based haptic environment for simultaneous training of reaching and grasping movements. It consists of a robot with three active and two passive degrees of freedom and a grasping device with one degree of freedom. A training scenario that includes a virtual physiotherapist is introduced. Presented are results of a preliminary study that requires reaching and grasping coordination. Index Terms— Rehabilitation robotics, grasping, upper ex- tremities, kinematics. I. INTRODUCTION Several pathologies result in reduced upper limb func- tionality. Motor recovery is a dynamic process that usually starts with a total incapacity to move the affected limb followed by development of some imprecise movements. After some time these movements become more precise but sometimes stiffness and involuntary activity hamper the return to functionality. Current therapeutic interventions for patients with severe brain injury such as stroke are based on neurofacilitatory techniques, muscle tonus controlling therapies, progressive strengthening, biofeedback or electrical stimulation [1], [2], [3]. Several studies have demonstrated the efficacy of differ- ent training therapies for arm paresis in stroke patients [3], [4] and that task-oriented therapies are important to improve the function of the affected arm [5]. There is evidence that machine delivered therapies can be effective in progressing the treatment [6]. Robotic devices are capable of reaction times far in advance of any human, which opens up the breadth of possible treatments, where robotic device responds to forces generated by the patient. For people with upper limb paralysis it is possible to consider therapies where intelligent assistance from a robot is able to provide varying degrees of compensatory movements for the affected limb. Evidence indicates that where patient is motivated and premeditates his movement, the recovery is more effective and intelligent machines allow a broad scope to investigate these conditions. Furthermore sensing that already exists within the robot can be used to provide a wealth of information about the underlying pathology. While many of the necessary technologies are in place to produce robot based rehabilitation devices with the right characteristics for rehabilitation, there is a major need to in- tegrate these and identify the optimum modalities of exercise This work was partially supported by the EU Information and Commu- nication Technologies Collaborative Project MIMICS grant 215756. Authors are with Faculty of Electrical Engineering, University of Ljubl- jana, Tr ˇ zaˇ ska c. 25, SI-1000 Ljubljana, Slovenia. Corresponding author: matjaz.mihelj@robo.fe.uni-lj.si from the point of view of motor training. Within traditional therapy there is considerable controversy surrounding the most appropriate method of therapy and there are still insuf- ficient data to identify clearly the benefits of these different approaches. A. Scientific Evidence for Automated Rehabilitation One question that needs to be answered is whether a device for rehabilitation of upper arm functions should include the possibility to train proximal as well as distal functions. In [7] authors conclude that a repetitive training of complex movements is not beneficial compared with functional-based occupational and physiotherapy. Instead, a well-defined repetitive training of circumscribed functionally most important activities, particularly of the hand, is recom- mended. This would suggest that a complex device dedicated to training of proximal and distal arm functions would be less beneficial compared to two separate devices, one for proximal and the other for distal arm functions. Evidence based physiotherapeutic concepts for improving arm and hand function in post stroke patients are analyzed in a review article [8]. Authors suggest that repetitive execution of complex movements is appropriate to support motor recovery in stroke patients and to accelerate its time course. In a study reviewing different devices for robot based rehabilitation of upper and lower extremities authors address the problem related to the rehabilitation of proximal versus distal upper arm functions in robot-assisted upper limb re- habilitation [9]. They note that arguments in favor of a more distal approach may be the larger cortical representation of the forearm and hand, and the presumed competition of proximal and distal body segments for recovery. The competition of the proximal and distal functions for territory in sensorimotor cortex was confirmed also in [10]. Authors showed that even limited activity of the upper arm might prevent the hand from gaining motor control. The lack of evidence is further supported by other studies. Insufficient evidence makes it impossible to draw definite conclusions about the effectiveness of exercise therapy on arm function in stroke patients [11]. The difference in results between studies with and without contrast in the amount of duration of exercise therapy between groups suggests that more exercise therapy may be beneficial. The messages resulting from the review are as follows: 1) trials comparing different types of exercise therapy for the arm function in stroke patients have shown no difference in effectiveness, 2) more intensive exercise therapy appears to be beneficial and 3) stroke patient should be encouraged to continue exercising the affected arm. Proceedings of the 2nd Biennial IEEE/RAS-EMBS International Conference on Biomedical Robotics and Biomechatronics Scottsdale, AZ, USA, October 19-22, 2008 978-1-4244-2883-0/08/$25.00 ©2008 IEEE 907