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建立一个步态过程中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，即身体一侧虚弱。由于受伤或中风等神经疾病造成的这种虚弱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。步态康复到目前为止还不是很成功的一个主要原因是对健全者和受损者的步态动力学缺乏基本的了解。该领域面临的一个重大科学挑战是创建一个全面的感觉运动模型，该模型可以用来理解腿间协调，这是行走的基本机制。由一种新型机器人可变刚度跑步机实现的实验将用于模拟偏瘫患者的行走步态，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，包括矫形学和假肢，以及机器人步行器。该项目将解决与步态过程中腿间协调机制有关的重要研究问题，这将为变革性步态再训练方法提供基础。更具体地说，由可变刚度跑步机实现的对感觉反馈对腿间协调神经肌肉机制影响的独特研究，将被用作了解步态感觉运动控制机制的窗口。机器人再训练步态干预的系统动力学和控制方法将增强我们对步态中感觉-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导致引入基于模型的干预措施，使用腿间耦合进行步态治疗，这是以前从未尝试过的。具体地说，该项目利用了现有的腿部协调的中央机制，并通过对未受损的腿部进行基于模型的干预，引入了在瘫痪腿上激发活动的概念。腿间协调是步行的一个基本过程，我们将利用可变刚度跑步机独特的感觉-运动能力，将其研究并建模为完整步行者的多变量动力系统。然后，同样的实验方案将应用于偏瘫步行者。我们的目标是了解偏瘫时改变的动力学和特定的步态机制和路径。最后，开发的模型将导致对中风幸存者的步态治疗进行有针对性的基于模型的干预。

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.