The overall aim of the RETRAINER project is to tune and validate advanced, robot-based technologies to facilitate recovery of arm and hand function in stroke survivors and to extensively verify the use of the system by patients and clinicians. RETRAINER allows end-users to use their own arm and hand as much and as soon as possible after the trauma so to achieve the best outcomes in rehabilitation.
Every year, about 16 million first ever strokes occur in the world, causing 5.7 million deaths. As a consequence, stroke ranks as the second cause of death in the world population. In the EU, total annual cost of stroke is estimated €27 billion. A further sum of €11.1 billion is calculated for the value of informal care.
RETRAINER, as an innovation action, implements a full technology transfer from the results of a previous FP7 project, MUNDUS. RETRAINER makes available two systems for stroke rehabilitation, both derived from a subset of the MUNDUS project: S1, which aims at training the arm movements, and S2, which aims at training the hand movements.
RETRAINER S1 provides the end-user with a robot that does not completely take over the user’s tasks and does not substitute the body’s functionality, but specifically supports the user only wherever he/she really needs support. Residual functionality is trained and improved rather than replaced by the robotic device. Arm movements are supported by a combined action of a passive exoskeleton for weight relief and NMES delivered to arm muscles in a controlled manner. Stimulation amplitudes control is based on the residual EMG activities of the same stimulated muscles since the combination of NMES with the voluntary effort of the patients seems to maximize the therapeutic effects of NMES.
RETRAINER S2 takes care of the training of hand functions through a wearable NMES system with multiple electrode arrays, a modular tool usable as a platform for grasp rehabilitation, potentially improving the clinical applicability of NMES. The device is designed for providing electrical stimulation on extrinsic and intrinsic grasp muscles. The stimulation patterns can be manually tuned to elicit functional grasp, to obtain whole muscle conditioning, and to produce open-loop or closed-loop grasp control.
Both systems benefit from the use of interactive objects that are daily life objects able to supply the robotic system with some information on themselves (e.g. physical characteristics, expected sequence of use) to drive their usage. Within RETRAINER, this concept is exploited to drive rehabilitation exercises to get deeper knowledge on the recovery of the patient.
The S1 and S2 systems have been validated through a multicentre clinical trial conducted in Italy and Germany on 136 patients. The trial aimed at assessing the effectiveness of the RETRAINER rehabilitation systems against the conventional therapy on one side, and at evaluating the usability of the protypes in daily practice in clinical environment. The results showed that the S1 training has superior effects and S2 a comparable effect with respect to the conventional therapy. On the usability side, the two system have been extensively used for over 2 years autonomously by therapists in their daily activities, showing a high degree of robustness and easiness of use.
