Novel Control For A Post Stroke Gait Rehabilitation Exoskeleton

Stroke is the second highest cause of death worldwide and the third leading cause of adult disability across all age brackets. Recovering gait following stroke is a major goal of patients, and hence rehabilitation, as it is central to many activities of daily living. Of the different treatment modalities, robotic assisted gait training is growing in popularity, but is still considered complementary to, and not substitute for conventional therapies comprising physiotherapy, overground walking and body weight supported treadmill training. The potential advantages that lower limb robotics bring to neurorehabilitation over conventional therapies include, higher dosage, specificity, improved consistency, and duration, though these benefits have been slow to manifest. Exoskeletons are well placed to provide these benefits, as well as environmental variation and task salience if they can be used away from outpatient settings. Control strategies that may be enhancing of recovery are often confined to stationary exoskeletons, and the control of mobile exoskeletons is only loosely related to gait, if at all, which limits rehabilitation outcomes. -- The primary aim of this PhD thesis was to develop an adaptive, user-initiated gait Controller that aims to target a novel neural recovery pathway. The Controller would use a robotic exoskeleton, with the intention of developing novel neuroplasticity that is beneficial for gait and would be permissive of simultaneous control of hip and knee posture. A theoretical framework based on the principles of neuroplasticity was proposed that seeks to bring higher engagement, task variance, and volition to gait rehabilitation. This framework considers stroke and rehabilitation timelines and the interaction of the proposal with existing theory, how beneficial neuroplasticity may manifest, and how the proposal may be detrimental. A comprehensive survey of candidate lower limb devices followed (164 devices), to understand exactly what features are compatible, complementary, or contradictory to the proposed control method, and to understand the implications the various specifications have. Specifically, it was found that ambulating exoskeletons that can move around the environment were preferred for their ability to be used in the community and the home, and that extended joint range of motion will be permissive of activities that are supportive of gait such as sit-to-stand and stair ascent/descent. Of the various control systems that have been implemented with exoskeleton devices, trajectory control, where motion is enforced on the limb by the exoskeleton, is preferred. -- The method of control was assessed for suitability as a gait controller through a participant study (n = 21). Participants were asked to reproduce the motion required for the controller, and with minor modification to participant motion it was shown that reliable control signals can be obtained. The remainder of the thesis applies the learnings of the previous stages in the development of the Controller and an accompanying Sensor. The custom Sensor was designed with a small form factor to be applied on the Controller. The thesis concludes with an implementation of the Controller and a successful demonstration of the proposed concept, where the control signals are reproduced on a scale lower limb exoskeleton. The full technical detail and specification of the Controller, and the custom position Sensor developed specific for this application, are presented as part of this work. -- This work has added a new theoretical framework for gait control following stroke and has added technological capability to implement the proposal. It is the primary recommendation of this PhD that the novel control method be tested further with participant studies and that the component hardware be developed further. Therapies targeting novel recovery mechanisms breathe fresh air into rehabilitation and may inspire other new treatments, and future funded work originating from this PhD will see the concept tested with a chronic stroke population, using an ambulating exoskeleton and the Controller.

The book provides readers with a comprehensive overview of the state of the art in the field of gait and balance rehabilitation. It describes technologies and devices together with the requirements and factors to be considered during their application in clinical settings. The book covers physiological and pathophysiological basis of locomotion and posture control, describes integrated approaches for the treatment of neurological diseases and spinal cord injury, as well as important principles for designing appropriate clinical studies. It presents computer and robotic technologies currently used in rehabilitation, such as exoskeleton devices, functional electrical stimulation, virtual reality and many more, highlighting the main advantages and challenges both from the clinical and engineering perspective. Written in an easy-to-understand style, the book is intended for people with different background and expertise, including medical and engineering students, clinicians and physiotherapists, as well as technical developers of rehabilitation systems and their corresponding human-compute interfaces. It aims at fostering an increased awareness of available technologies for balance and gait rehabilitation, as well as a better communication and collaboration between their users and developers.

The concepts represented in this textbook are explored for the first time in assistive and rehabilitation robotics, which is the combination of physical, cognitive, and social human-robot interaction to empower gait rehabilitation and assist human mobility. The aim is to consolidate the methodologies, modules, and technologies implemented in lower-limb exoskeletons, smart walkers, and social robots when human gait assistance and rehabilitation are the primary targets. This book presents the combination of emergent technologies in healthcare applications and robotics science, such as soft robotics, force control, novel sensing methods, brain-computer interfaces, serious games, automatic learning, and motion planning. From the clinical perspective, case studies are presented for testing and evaluating how those robots interact with humans, analyzing acceptance, perception, biomechanics factors, and physiological mechanisms of recovery during the robotic assistance or therapy. Interfacing Humans and Robots for Gait Assistance and Rehabilitation will enable undergraduate and graduate students of biomedical engineering, rehabilitation engineering, robotics, and health sciences to understand the clinical needs, technology, and science of human-robot interaction behind robotic devices for rehabilitation, and the evidence and implications related to the implementation of those devices in actual therapy and daily life applications.

Rehabilitation Robotics gives an introduction and overview of all areas of rehabilitation robotics, perfect for anyone new to the field. It also summarizes available robot technologies and their application to different pathologies for skilled researchers and clinicians. The editors have been involved in the development and application of robotic devices for neurorehabilitation for more than 15 years. This experience using several commercial devices for robotic rehabilitation has enabled them to develop the know-how and expertise necessary to guide those seeking comprehensive understanding of this topic. Each chapter is written by an expert in the respective field, pulling in perspectives from both engineers and clinicians to present a multi-disciplinary view. The book targets the implementation of efficient robot strategies to facilitate the re-acquisition of motor skills. This technology incorporates the outcomes of behavioral studies on motor learning and its neural correlates into the design, implementation and validation of robot agents that behave as ‘optimal’ trainers, efficiently exploiting the structure and plasticity of the human sensorimotor systems. In this context, human-robot interaction plays a paramount role, at both the physical and cognitive level, toward achieving a symbiotic interaction where the human body and the robot can benefit from each other’s dynamics. Provides a comprehensive review of recent developments in the area of rehabilitation robotics Includes information on both therapeutic and assistive robots Focuses on the state-of-the-art and representative advancements in the design, control, analysis, implementation and validation of rehabilitation robotic systems

C-ALEX was designed for gait training and rehabilitation, and its training effectiveness was studied in nine healthy subjects and a stroke patient. The healthy subjects trained with C-ALEX to walk in a new gait pattern with 30% increase in step height for 40 min. After the training, the subjects were able to closely repeat the trained gait pattern without C-ALEX, and the step height of the subjects increased significantly. A stroke patient also tested C-ALEX for 40 minutes and showed short-term improvements in step length, step height, and knee flexion after training. The result showed the effectiveness of C-ALEX in gait training and its potential to be used in stroke rehabilitation.

Every two minutes, 3 people in the United States will have a stroke and every hour an American baby is born with cerebral palsy. The only method available to recover from motor impairments associated with these brain injuries is time-consuming labor intensive physical and occupational therapy. Upper extremity rehabilitation robotics is well established and recommended by the American Heart Association, the Veterans Administration, and the Department of Defense; however, lower extremity rehabilitation robots are still in their infancy, so far leading to inferior results when compared to manual methods in the only available sizable randomized control trials. Thus, there exists an urgent need for novel methods to augment gait rehabilitation. This thesis outlines the design and development of a novel gait rehabilitation robot, the MIT-Skywalker, that enables the exploration of new methods of gait rehabilitation based on current understanding of the neuroscience of motor control. Because each patient's impairment is unique, the MIT-Skywalker system creates a flexible environment that accommodates a wide spectrum of pathological gaits. It can operate in three unique modes. The first promotes the rhythmicity of walking by removing the floor constraint during the swing phase of walking. The second mode fosters discrete start and stop movements and focuses on the accuracy of heel placement. Finally, a balance program perturbs gait in the frontal plane to engage balance mechanisms. A one-month feasibility study with the MIT-Skywalker demonstrated positive outcomes for two adults with impairments due to cerebral palsy and one person with chronic stroke and proved the safety and viability of each training mode.