Modeling and Analysis of Sensorimotor Dynamics in Inter-leg Coupling Leads to a Novel Model-based Approach to Human Gait Rehabilitation

这个项目的主要研究目标是创建一个步态中双腿之间协调的动态模型，并将该模型应用于偏瘫患者的康复，偏瘫是指身体的一侧无力。这种虚弱——由于受伤或中风等神经系统疾病——以及与之相关的行走困难，已经成为一个紧迫的公共卫生问题。到目前为止，步态康复尚未非常成功的主要原因之一是缺乏对完整步行者和受损步行者步态动力学的基本理解。该领域面临的一个重大科学挑战是建立一个全面的感觉运动模型，该模型可用于理解腿间协调，这是行走的基本机制。一种新型机器人可变刚度跑步机的实验将用于模拟偏瘫患者的步行步态，并为基于模型的机器人康复干预提供信息。这种方法的好处也将在其他领域实现，包括矫形术和假肢，以及机器人行走器。该项目将解决与步态期间腿间协调机制相关的重要研究问题，这将为变革性步态再训练方法提供基础。更具体地说，通过可变刚度跑步机，对感觉反馈对腿间协调神经肌肉机制的影响的独特研究将被用作了解步态的感觉运动控制机制的窗口。机器人干预步态再训练的系统动力学和控制方法将增强我们对步态中涉及的感觉运动过程的作用的理解。理解和建模控制步态中腿间协调的感觉-运动机制的动力学，自然会引入基于模型的干预措施，利用腿间耦合进行步态治疗，这是以前从未尝试过的。具体而言，该项目利用了现有的腿部协调中心机制，并通过对未受损腿的基于模型的干预，引入了唤起残疾腿活动的概念。腿间协调是行走的一个基本过程，我们将利用可变刚度跑步机独特的感觉-运动能力，对完整步行者的多变量动力系统进行研究和建模。然后，同样的实验方案将应用于偏瘫步行者。目的是了解偏瘫中改变的动力学和特定的步态机制和通路。最后，开发的模型将导致针对中风幸存者步态治疗的基于模型的干预。

The main research goal of this project is to create a dynamic model of coordination between legs during gait, and to apply that model to rehabilitation of individuals suffering from hemiparesis, that is, weakness on one side of their body. Such weakness -- due to injury, or to a neurological disorder such as stroke -- and the associated difficulty in walking, has become a pressing public health problem. One of the main reasons gait rehabilitation has not been very successful so far is the lack of basic understanding of the dynamics of gait in both intact and impaired walkers. A major scientific challenge for the field is the creation of a comprehensive sensorimotor model, which can be used to understand inter-leg coordination, a fundamental mechanisms of walking. Experiments enabled by a novel robotic variable stiffness treadmill will be used to model walking gaits of individuals with hemiparesis, and to inform model-based robotic interventions for rehabilitation. The benefits of this approach will be also realized in other fields, including orthotics and prosthetics, as well as in robotic walkers. The project will address important research questions related to inter-leg coordination mechanisms during gait that will provide the foundation for transformative gait retraining methods. More specifically, the unique investigation of the effect of sensory feedback on neuromuscular mechanisms of inter-leg coordination, made possible by the Variable Stiffness Treadmill, will be used as a window into the sensorimotor control mechanisms of gait. A system dynamics and control approach to robotic intervention for retraining gait will enhance our understanding of the role of the sensori-motor processes involved in gait. Understanding and modeling the dynamics that govern the sensori-motor mechanisms of inter-leg coordination in gait naturally results in the introduction of model-based interventions for gait therapy using inter-leg coupling, which has never been attempted before. Specifically, the project leverages existing central mechanisms of leg coordination and introduces the concept of evoking activity on the paretic leg through model-based interventions on the unimpaired leg. Inter-leg coordination, a fundamental process of walking, is going to be investigated and modeled as a multivariable dynamical system in intact walkers using the unique sensori-motor capabilities of the Variable Stiffness Treadmill. Then, the same experimental protocol will be applied to hemiparetic walkers. The goal is to understand the altered dynamics and specific gait mechanisms and pathways that are disrupted in hemiparesis. Finally, the developed models will result in targeted model-based interventions towards gait therapy of stroke survivors.