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.
Prof Constantinos Mavroidis (Northeastern University) and Prof. Paolo Bonato (Spaulding Rehabilitation Hospital) and their teams have developed a wearable robotic brace (shown in Figure 1) called ANdROS (Active kNee Rehabilitation Orthotic System) that can assist post stroke patients in regaining a healthy gait pattern by applying corrective forces to the leg. Impact/benefits: In the United States each year about 795,000 people suffer a stroke, and approximately two-thirds of these individuals survive and require rehabilitation. Unfortunately, the rehabilitation process is labor intensive, as it often relies on a one-to-one administration of therapy. While the number of patients needing rehabilitation has increased, available resources have unfortunately been reduced, in part due to the organization of the health care / insurance system which typically covers only a very limited number of rehabilitation sessions. This situation challenges us to design innovative rehabilitation programs such as robotics based treatments. ANdROS could facilitate the recovery of an efficient and clinically desirable gait pattern in stroke patients via extensive retraining sessions. Furthermore, patients could wear the ANdROS during daily activities at home therefore extending rehabilitation outside of the hospital. Overview: The ANdROS is designed as a wearable and portable assistive tool for gait rehabilitation and monitoring. The exoskeleton frame consists of an actuated brace attached to the impaired leg via rigid straps, and a sensorized brace attached to the healthy leg via elastic straps (Figure 2). The ANdROS senses the position of the wearer’s thigh and shank with respect to their torso, as well as the interaction force between the patient and itself. The control algorithm allows ANdROS to detect the user’s intent and applies assistive forces to the patient when necessary (Figure 3).
