The present study aimed at investigating the effects of a novel robotic-aided rehabilitation treatment for the recovery of the upper limb related capabilities in chronic post stroke patients. Eighteen post-stroke patients were enrolled in a six weeks therapy program and divided in two groups. They were all required to perform horizontal pointing movements both in the presence of a robot-generated divergent force field (DF) that pushed their hands proportional to the trajectory error and perpendicular to the direction of motion, and according to the typical active assistive (AA) approach used in robotic therapy. We used a crossover experimental paradigm where the two groups switched from one therapy treatment to the other in opposite direction. The hypothesis undergoing this study was that the use of the destabilizing scenario forced the patient to keep the end-point position as closer as possible to the ideal path, hence requiring a more active control of the arm with respect to the AA approach. Our findings confirmed this hypothesis. In addition, when the DF treatment was provided in the first therapy cycle, patients showed straighter and smoother paths also during the subsequent AA therapy cycle, while this was not true in the opposite case. Concluding, the results herein reported provided evidence that the use of the unstable divergent force field can lead to better recovery outcomes, and therefore it is promising to be more effective than the solely therapy that assisted the subject.
Dr. Tropea is currently a post-doctoral associate at the Neural Engineering group at The BioRobotics Institute, Scuola Superiore Sant’Anna, Pisa. His main research interests account for the neuro-motor control mechanisms and the motor recovery process following a stroke to develop new control algorithms, functional assessment methods, and robotic-based rehabilitative strategies.
Dr. Cesqui is currently a post doctoral associate at the department of Neuromotor physiology of the Santa Lucia Foundation, Rome. Her main research interests are in the areas of upper limb motor control strategies, both in the framework of interceptive actions, and neurorehabilitation, eye movements, and virtual reality systems.
Dr. Monaco is currently an Assistant Professor at The BioRobotics Institute, Scuola Superiore Sant’Anna, Pisa. His main scientific interests account for the analysis of the modifications of motor control during daily activity due to aging and neuro-musculo-skeletal disorders, and fall biomechanics.
Dr. Aliboni is currently a medical doctor in the department of neurorehabilitation of Viareggio Hospital. Her main research and activity interests are in the areas of the upper limb motor control strategies, spasticity and treatment with botulinum toxin and orthosis, brain injury and also pediatric rehabilitation.
Mr. Posteraro is Director of Neurological Unit and Severe Brain Injury Unit of Auxilium Vitae Volterra. He has been working on the use of advanced technologies for many years with specific reference to neurological-derivated disability.
Dr. Micera is Associate Professor and Head of the Translational Neural Engineering Laboratory at the EPFL. His research interests include the development of hybrid neuroprosthetic systems (interfacing the central and peripheral nervous systems with artificial systems) and of mechatronic and robotic systems for function and assessment restoration in disabled and elderly persons.
This paper aims to investigate the effects of the combination of divergent force-field control (DF) and active-assist (AA) control for upper-limb recovery in post-stroke chronic patients. Though force field control has been introduced in gait rehabilitation as an assistive training paradigm, the idea of combining DF and AA control for an upper limb introduced in the paper is new and interesting. Clinical trials and assessments were performed to compare the DF and AA training paradigms. It’s important to observe that after training with the DF strategy in the first therapy cycle, the subsequent AA therapy cycle gave better outcomes.