CAREER: Neuromechanics of functional impairment of upper extremity following stroke and its effective restoration by retraining muscle activation patterns

Catholic University Of America, Washington DC

Investigators

Abstract

PI: Lee, Sang Wook Proposal Number: 1452763 The proposed project is a multi-year program of interdisciplinary research and educational activities that investigate neurological and biomechanical factors associated with functional impairment of the arm and hand post-stroke. While devastating impact of stroke on both lower and upper extremity function has been recognized, functional impairment of the upper extremity (arm and hand) is found to be particularly more severe. Thus there is an urgent need for the development of an effective strategy to reverse damaging impact on the upper extremity functionality for stroke survivors. But complexity of neurological abnormalities associated with the upper extremity impairment, along with its sophisticated biomechanics, poses substantial challenges to understanding neuromechanical processes associated with the functional impairment of upper extremity following stroke. The novel experimental and modeling methods proposed in the study will help clarify such mechanisms of the upper extremity impairment post-stroke, and the outcome of the proposed project will be of great interest to scientists studying neurophysiology and neuroscience of stroke, engineers designing rehabilitative devices for stroke survivors, and physicians and therapists treating them. More importantly, improved rehabilitation outcomes resulting from the proposed novel training method will benefit patients as their quality of life will be greatly improved. In addition, the proposed collaborative research activities will strengthen the relationship between the Catholic University of America and the nation?s leading clinics, the National Rehabilitation Hospital and the Rehabilitation Institute of Chicago, and will provide students with unique educational opportunities, including enhanced laboratory experience, clinical work with patients and physicians, and hands-on work experience in nation's leading rehabilitation hospitals. This award is being made jointly by two Programs: (1) Biomedical Engineering, (2) General and Age Related Disabilities Engineering, both in the Chemical, Bioengineering, Environmental and Transport Systems Division in the Engineering Directorate. This CAREER project attempts to elucidate key aspects of the neuromechanical process of the upper extremity functional impairment post-stroke, and to develop a novel strategy to improve upper extremity functionality of the stroke patients. Accordingly, the first two aims examine the following aspects of the functional impairment of upper extremity post-stroke: 1) neurological abnormalities affecting multi-muscle control, and 2) biomechanical pathway that such abnormalities translate into functional impairment. The proposed modeling methods clearly differ from existing approaches, as neurological abnormalities in multi-muscle control will be examined in a system perspective, rather than focusing on individual components (aim 1); and the proposed biomechanical model is based on "force-based" modeling, which contrasts to conventional "moment-based" modeling techniques (aim 2). The knowledge gained from these aims will be utilized to pursue the third aim of the project (aim 3), which is to develop biomimetic devices that can effectively promote neural plasticity of patients; a new type of devices driven by "exotendons", emulating human musculotendon anatomy, will be developed, which will enable a unique rehabilitation training method, i.e., targeted assistance of impaired muscles (aim 4). This assistance technique presents a new approach that focuses on restoration of muscle coordination, which is fundamentally different from existing approaches that attempt to restore kinematics, and is expected to greatly improve rehabilitative benefits of the training. The pursuit of the proposed project will also provide unique educational opportunities for students in the School of Engineering of the Catholic University of America. Interacting with an interdisciplinary team of engineers, physicians, and therapists, students will have clinical, hands-on work experience in top-ranked rehabilitation hospitals. The investigator plans to particularly engage students from underrepresented group (i.e., Hispanic origin) in the research projects, for which they will work closely with patients on "patient-specific" device design. Research topics covered by the proposed project will also be incorporated into the curriculum. Furthermore, the educational benefit of the proposed project will be extended to K-12 STEM education via a series of "case-study" presentations by the undergraduate interns to K-12 students within the District of Columbia Public School System. The broad spectrum of topics addressed by this project, including biomechanics, biological system modeling, neural signal/processing, and device design is expected to greatly improve students' "hands-on" experience, and research opportunities provided by the proposed activities will greatly help them prepare for their careers as successful biomedical engineers.