GOALI: Active Knee Rehabilitation Orthotic Device with Variable-Damping Characteristics For Stroke Patient Rehabilitation

Northeastern University, Boston MA

Investigators

Abstract

PI: Mavroidis, Constantinos Proposal Number: 0828772 Stroke is the third leading cause of death in the United States; with approximately 730,300 new cases and about 160,000 deaths in the United States annually. Approximately 80% of stroke survivors present an early motor deficit, with about 50% having chronic deficits. Loss of mobility due to muscle weakness and spasticity and thus impaired gait is a major contributor to post-stroke disability. Novel treatments are needed to serve as training aids for reestablishing efficient gait patterns, and as assistive devices to address residual motor impairments and functional limitations. During the last ten years, robotics and mechatronics have emerged as new research areas of great relevance to rehabilitation. Robotics and mechatronics offer the promise of sensitive, objective measurements and mobility assistance by using novel wearable and computer controlled active devices. The proposed project brings together experts in robotics, precision manufacturing, biomechanics, and stroke medicine with the goal of considerably improving the quality of life of stroke patients. The research goals of this project are to develop and test a novel, smart and portable Active Knee Rehabilitation Orthotic Device (AKROD) designed to train stroke patients to correct knee hyperextension during stance and stiff-legged gait (defined as reduced knee flexion during swing). The knee brace will provide variable damping and torque actuator capabilities controlled in ways that we hypothesize foster motor recovery in stroke patients. Two different components of the device will be developed: a resistive (variable damper) and an active (torque actuator) component. The variable damper component of the brace will be used to facilitate knee flexion during stance by providing resistance to knee buckling. Furthermore, the knee brace will be used to assist in knee control during swing, i.e. to allow patients to achieve adequate knee flexion for toe clearance and adequate knee extension in preparation to heel strike. The torque actuator component will be used to encourage patients to actively extend the knee during midto-terminal stance, facilitate knee flexion during initial swing, and again encourage knee extension during mid-to-terminal swing. Algorithms for establishing appropriate control of the knee brace will be developed. Using data from both normal volunteers and hemiplegic stroke survivors, we will create training programs for the knee orthosis to assist patients in re-establishing a natural gait pattern. The intellectual merit of the proposed project is the major enhancement of gait retraining in stroke patients and considerable improvement of orthotic intervention in the home and community settings. A wearable and portable smart training orthosis, as the one developed and tested in this project, could be used by patients throughout daily activities, with constant reinforcement of the targeted gait pattern. This constant reinforcement of gait retraining in a real-world environment has the potential to provide more effective and faster gait retraining, improving one's ability to ambulate. The educational, broader impact and outreach activities of this project include: the initiation of undergraduate students in research, the establishment of collaborative projects in biomedical engineering and robotics with the science and technology high schools of Massachusetts, the organization of a conference special session, a seminar series and a webpage on portable and wearable rehabilitation devices, the performance of graduate and undergraduate student internships in industry, and, in partnership with NU's School of Technological Entrepreneurship (STE), the organization of a one semester I-cubator (student)project on market analysis and business planning for new technologies on wearable active knee orthoses. This 3-year GOALI project will be performed jointly by Northeastern University (NU) of Boston, MA, Spaulding Rehabilitation Hospital (SRH) of Boston, MA (a Harvard Medical School affiliated institution) and WGI Inc. of Southwick, MA.