Investigation of Transtibial Amputee Ability to Coordinate Residual Antagonistic Muscle Activations with Direct Electromyographic Control for the Enhancement of Postural Control

项目摘要 控制站立姿势的能力是日常生活的一个重要方面，这种能力在下肢运动中会发生变化。 截肢者随着主动踝关节控制的丧失，截肢者的稳定性和适应性代偿性下降 控制策略，有利于他们的完整肢体。已经做了少量的工作来辅助姿势控制 使用动力踝关节假体，尽管这种控制不适合由于动力踝关节假体引起的预期扰动的情况， 只产生反应的能力。规范性反应包括踝关节的预期变化- 在扰动发生之前的力学。直接肌电图（EMG）控制提供了一种手段， 通过下行神经指令来恢复姿势控制， 在假肢踝关节的机制。目前的工作只测试了直接肌电控制的潜力， 动力假肢只有单肌肉输入或循环任务（如步行）。姿势控制机制 需要来自对抗性踝部肌肉的协调控制以产生相互和共激活的模式 在踝关节。目前尚不清楚截肢者是否能够协调残余的肌肉激活， 如果使用动力踝假体直接EMG控制可以在预期扰动下辅助姿势控制。 我的工作目标是对残余拮抗性小腿肌有更深入的了解 作为控制源，以帮助恢复在截肢踝关节处产生姿势控制机制的能力。 这项拟议中的研究将促进我的长期目标，即开发技术， 功能和截肢者的生活质量。具体地，来自残余拮抗肌的直接EMG控制可以 通过下行神经命令利用人类意图，允许预期调制 假肢踝关节力学因此，我提出以下研究目标：1）研究残差 拮抗肌作为直接EMG控制的输入; 2）评估经胫骨截肢者 使用带有拮抗性残余肌肉的动力踝关节假体的直接EMG控制来产生姿势 预期扰动下的控制机制。 为了实现我的目标，我将在虚拟系统中测试残余拮抗肌和动力踝关节的能力 假体分开我将使用两个虚拟系统来测试截肢者的能力， 激活和共激活; 2）控制一个高度动态的系统。我将量化完成这两项任务的能力 任务，并分析相关性能。然后，我将使用预期扰动测试范例， 测试截肢者使用动力踝关节假体的直接EMG控制来增强姿势控制的能力。 我将量化动力假肢踝关节对整体稳定性的贡献。总的来说，成果将提供 更深入地了解残余拮抗肌作为控制源，并证明 直接EMG控制，用于恢复假肢踝关节的姿势控制机制。无创 我的工作性质也有很大的潜力，直接肌电控制的临床翻译。

PROJECT SUMMARY The ability to control standing posture is an essential aspect of daily living and this ability is altered for lower-limb amputees. With the loss of active ankle joint control, amputees have decreased stability and adapt compensatory strategies of control, favoring their intact limb. A small amount of work has been done to assist postural control with a powered ankle prosthesis, though this control is ill-fitted for situations of expected perturbation due to the ability to produce only reactive responses. Normative responses involve anticipatory changes in ankle- mechanics before a perturbation occurs. Direct electromyographic (EMG) control provides promise as a means of incorporating high-level human intent via descending neural commands for the restoration of postural control mechanisms at the prosthetic ankle joint. Current work has only tested the potential for direct EMG control of a powered prosthesis with only single-muscle input or with cyclic tasks (like walking). Postural control mechanisms require coordinated control from antagonistic ankle muscles to generate patterns of reciprocal and coactivation at the ankle-joint. It is unknown then whether amputees are able to coordinate residual muscle activations and if direct EMG control with a powered ankle prosthesis can assist postural control under expected perturbation. The objective of my proposed work is to develop a deeper understanding of residual antagonistic shank muscles as a control source to help restore the ability to generate postural control mechanisms at the amputated ankle. The proposed research will facilitate my long-term goal of developing technology that will improves prosthesis functionality and amputee quality of life. Specifically, direct EMG control from residual antagonistic muscle can take advantage of human intent via descending neural commands, allowing for anticipatory modulation of prosthetic ankle-joint mechanics. Thus, I propose the following research aims: 1) To investigate residual antagonistic muscle as an input for direct EMG control; and 2) To assess the extent to which transtibial amputees use direct EMG control of a powered ankle prosthesis with antagonistic residual muscles to generate postural control mechanisms under expected perturbations. To execute my aims, I will test the ability of residual antagonist muscles in a virtual system and powered ankle prosthesis separately. I will use two virtual systems to test the ability for amputees to 1) generate varying levels of activation and coactivation and 2) control a highly dynamic system. I will quantify the ability to complete both tasks and analyze the correlation in performance. I will then use an expected perturbation testing paradigm to test the ability for amputees to use direct EMG control of a powered ankle prosthesis to enhance postural control. I will quantify the contribution of the powered prosthetic ankle to overall stability. Overall the outcomes will provide a deeper understanding of residual antagonist muscles as a control source and demonstrate the feasibility of direct EMG control for the restoration of postural control mechanisms at the prosthetic ankle. The non-invasive nature of my work also has great potential for clinical translations of direct EMG control.