CHS: Small: Feedback-based Stroke Rehabilitation Using Multiple Simultaneous Therapies

Walking is a fundamental daily activity, and independent walking is a primary goal for individuals with a stroke. However, less than 22% of people with a stroke are able to regain sufficient functional walking to be considered independent community ambulators. Many individuals with a stroke have asymmetric walking patterns (e.g., different step lengths with each leg) that reduce walking efficiency, decrease walking speed, and increase the likelihood of injuries and falls. To get a feel for asymmetric gait, one can try wearing a thick-soled heavy shoe on one foot and go barefoot on the other; then try to walk with the same step length on each foot while maintaining a consistent timing between placing each foot on the ground. This simple perturbation will likely modify the gait such that the person has to push harder with one leg during walking. In contrast to the one perturbation in this example, each of the millions of individuals with a stroke have multiple asymmetric changes that compound the detrimental effects. While there are many different therapies to help individuals regain their walking ability, disabilities are unique and often need a solution specific to each person. This project will use a combination of existing therapies applied simultaneously to generate a user-specific therapy that adapts to the individual's needs. This project focuses on gait rehabilitation after a stroke but may lead to benefits in therapies for gait recovery in individuals with lower limb amputations, hemiparetic cerebral palsy, and other gait impairments. This project addresses research questions such as: (i) what is the level of the symmetry that can potentially be targeted for a patient that has inherent asymmetry in functionality; (ii) what factors influence the perception of a symmetric gait; (iii) how to model the interactions among multiple therapies used for rehabilitation. To answer these questions, the research team will first understand how the effects from two different therapies combine. Based on the results of multiple pairs of simultaneous therapies, the second phase will use real-time feedback, based on the measured gait to optimize the output from two or more individual therapies. Controlling multiple therapies should allow for the control of multiple gait parameters that can change the gait pattern in a user-specific way. Since individuals with a stroke inherently have different force and motion capabilities on each leg, perfect symmetry may not be possible. Throughout this project, experiments will determine the bounds of acceptable asymmetry from a visual perspective. This perception will help understand what clinical physical therapists perceive about gait and help direct their attention to important parameters, particularly those that both have a large impact on gait function but are not easily perceived. Although the resulting gait may have some degree of asymmetry in all measures, the gait pattern will likely be less visually noticeable and meet the functional walking goals of individuals with asymmetric impairments. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.