Closed-Loop Control and Operant Conditioning of Loading Response during Locomotion After Stroke

中风后运动期间负载响应的闭环控制和操作条件

• 批准号: 2218913
• 负责人: Victor Duenas
• 金额: $ 36.64万
• 依托单位: Syracuse University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-10-01 至 2025-09-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2218913&HistoricalAwards=false
• 关键词: Closed; Loop; Control; Operant; Conditioning

Individuals after stroke often struggle to use their stroke-affected leg to propel themselves during walking. Due to this partial disuse of the affected leg and in compensation to that, people walk slowly and with more effort. Despite advances in exoskeleton technologies and robotic gait rehabilitation in improving gait energetics and speed, it remains challenging to yield sustaining improvements in leg function. In people after stroke, the activation of lower leg muscles and generated forces are diminished, and the ankle joint motion that is critically important for walking is impaired. The goal of this project is to develop a novel gait training method to augment the function of the stroke-affected leg by targeting the ankle joint and its muscles to increase walking power. This project will use a wearable robotic device to impose small movement perturbations about the ankle to strategically activate stroke-affected ankle muscles during walking. A unique conditioning training protocol will be designed to increase the person’s ankle muscle activity and force to propel the body forward during walking. This project will advance fundamental knowledge to enhance the muscle power and propulsion, which is a key barrier to improving gait after stroke. Educational and outreach impact: middle and high school students and teachers with disabilities will have opportunities to be exposed to the wearables and gait-assistance technologies through hands-on lessons in a workshop setting. Broader outreach impact includes a public forum for sharing findings from this project and raising disability awareness with people at the local stroke support group. Undergraduate researchers from underrepresented groups and minorities will be encouraged to participate in these training and dissemination activities. This project seeks to achieve a paradigm shift in neuro-behavioral gait training by integrating a novel operant conditioning protocol and a robotic ankle device to enhance paretic leg function post-stroke. The innovation in this project is the development of a hybrid approach to target the soleus muscle activity within the stance phase of walking and condition its loading response as a strategy to improve hemiparetic walking. The research plan includes two objectives with testing in people post-stroke and able-bodied individuals. Objective 1 will characterize the input-output property of the ankle plantarflexors’ loading response in stance phase. An adaptive closed-loop control algorithm will be designed and evaluated to apply ankle joint rotations using the wearable robot. The joint perturbations will be shifted from the natural ankle kinematics to target the soleus loading response, i.e., activate load sensing Ib afferents, in mid-late stance phase. The closed-loop algorithm will be systematically investigated to customize the perturbation magnitude, speed, and timing for each participant. Changes in soleus electromyography (EMG), joint kinematics, and propulsion will be quantified between perturbed and unperturbed step cycles during one treadmill walking session in 15 participants post-stroke. Findings from this objective will provide insights into the methods to modulate the soleus loading response by manipulating ankle kinematics through applied, controlled joint perturbations using the wearable device (i.e., emulate imposed dorsiflexions during normal gait). Objective 2 will develop a dynamic protocol to enhance (operantly up-condition) the soleus loading response during treadmill walking. With operant conditioning of the EMG evoked response, participants will be rewarded for enhancing the soleus loading response through visual feedback. The conditioning protocol will be implemented in 8 able-bodied individuals to quantify soleus EMG, joint kinematics, and propulsion throughout 6 baseline and 24 conditioning sessions. Findings from this objective will help to advance the knowledge to target and enhance the excitability of Ib pathways to increasing soleus activity and propulsive force generation.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.

中风后的人在走路时往往很难使用受中风影响的腿来推动自己。由于受影响的腿被部分停用，作为补偿，人们走路缓慢，而且更加努力。尽管外骨骼技术和机器人步态康复在提高步态能量和速度方面取得了进展，但要持续改善腿部功能仍然具有挑战性。中风后，小腿肌肉的激活和所产生的力量会减少，对行走至关重要的脚踝关节运动也会受到损害。该项目的目标是开发一种新的步态训练方法，通过靶向踝关节及其肌肉来增强中风患者腿部的功能，以增加步行能力。该项目将使用一种可穿戴的机器人设备来施加脚踝周围的微小运动扰动，以便在行走过程中战略性地激活受中风影响的脚踝肌肉。将设计一种独特的条件训练方案，以增加人的脚踝肌肉活动和力量，以推动身体在行走过程中向前推进。该项目将提高基础知识，以增强肌肉的力量和推进力，这是改善中风后步态的关键障碍。教育和外展影响：初高中残疾学生和教师将有机会通过研讨会环境中的实践课程接触到可穿戴设备和步态辅助技术。更广泛的外展影响包括一个公共论坛，用于分享该项目的结果，并提高当地中风支持小组的人们对残疾的认识。将鼓励来自代表性不足群体和少数群体的本科生研究人员参加这些培训和传播活动。该项目旨在通过集成一种新的操作条件调节方案和机器人脚踝设备来实现神经行为步态训练的范式转变，以增强中风后偏瘫患者的腿部功能。该项目的创新之处在于开发了一种混合方法，在行走的站立阶段针对比目鱼肌的活动，并将其负荷反应作为改善偏瘫行走的一种策略。该研究计划包括两个目标，分别是在中风后患者和健全个体中进行测试。目的1描述踝趾屈肌在站立时负荷响应的输入输出特性。将设计和评估一种自适应闭环控制算法来应用可穿戴机器人的踝关节旋转。在中晚期站立阶段，关节扰动将从自然的踝关节运动学转移到比目鱼肌的负荷响应，即激活负荷感应Ib传入。将系统地研究闭环系统算法，以定制每个参与者的扰动幅度、速度和定时。在15名中风后参与者的一次跑步机步行过程中，比目鱼肌肌电(EMG)、关节运动学和推进力的变化将在扰动和非扰动踏步周期之间进行量化。这一目标的发现将为通过使用可穿戴设备(即在正常步态中模拟强制背屈)通过应用的、可控的关节扰动来操纵脚踝运动学来调节比目鱼肌负荷响应的方法提供洞察力。目标2将开发一种动态方案来增强跑步机行走过程中比目鱼肌的负荷反应。随着肌电诱发反应的可操作性条件反射，参与者将获得通过视觉反馈增强比目鱼肌负荷反应的奖励。训练方案将在8名身体健全的人身上实施，以量化比目鱼肌肌电、关节运动学和推进力，贯穿6个基线和24个训练阶段。这一目标的发现将有助于将知识推向目标，并增强Ib通路的兴奋性，以增加比目鱼肌的活动度和推进力的产生。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。