Haptic Systems for Post-Stroke Rehabilitation: from Virtual Reality to Remote Rehabilitation

Haptic devices are becoming a common and significant tool in the perspective of robotic neurorehabilitation for motor learning, particularly in post-stroke patients. As a standard approach, this kind of devices are used in a local environment, where the patient interacts with a virtual environment recreated in the computer's screen. In this sense, a general framework for virtual reality based rehabilitation was developed. All the features of the framework, such as the control loop and the external communication, as well as the haptic and graphic rendering, were implemented inside Matlab/Simulink using Handshake proSENSE toolbox, guaranteeing a real-time system. As an example, a five-bar linkage haptic device with two active degrees-of-freedom (DOF) was designed and integrated within the proposed framework, as well as a device for grasping operations. An extension of this standard approach is verified when the therapist is allowed to feel and interact remotely and in real time with the patient. We applied the proposed concept to a single degree-of-freedom master/slave system. One hand orthosis was used as a master device at the therapist's side, while the other was applied to the patient's hand, and used as a slave device. In order to achieve this issue, we proposed two bilateral control systems in order to guarantee an stable interaction between the master and the slave, even in case of variable network conditions (i.e. Internet). By using the master device, the therapist can remotely move the patient's hand and, at the same time, perceive the patient's resistance to the motion, allowing the assessment of important parameters, such as the residual level of spasticity. In this way, it can be remotely assessed the conditions of the patient and consequently can be proposed a proper rehabilitation program.