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

项目总结 控制站立姿势的能力是日常生活中的一个基本方面，而这种能力对于下肢来说是不同的。 截肢者。随着踝关节主动控制的丧失，截肢者的稳定性降低，并适应代偿。 控制的策略，偏爱它们完整的肢体。已经做了少量的工作来帮助控制姿势 使用动力脚踝假体，尽管这种控制不适合预期的扰动情况，因为 能够只产生反应性反应。规范性反应涉及脚踝的预期变化- 微扰发生前的力学。直接肌电(EMG)控制作为一种手段前景看好 通过下行神经指令结合人类高级意图以恢复姿势控制 假肢踝关节的机械装置。目前的工作只测试了直接肌电控制的可能性 仅有单肌肉输入或具有周期性任务(如行走)的动力假体。姿势控制机制 需要来自对抗的脚踝肌肉的协调控制，以产生相互和协同激活的模式 在脚踝关节。目前尚不清楚截肢者是否能够协调剩余肌肉激活和 如果使用动力踝关节假体的直接肌电控制可以在预期的扰动下辅助姿势控制。 我所提议的工作的目的是加深对残存的拮抗小腿肌肉的理解。 作为控制源，以帮助恢复在截肢脚踝处产生姿势控制机构的能力。 这项拟议的研究将有助于我开发改进假肢的技术的长期目标 功能和截肢者的生活质量。具体地说，来自残留拮抗肌肉的直接肌电控制可以 通过下行的神经命令利用人类的意图，允许对 假肢踝关节力学。因此，我提出了以下研究目标：1)残差调查 拮抗肌肉作为直接肌电控制的输入；以及2)评估经胫骨截肢者的程度 使用肌电直接控制具有对抗残馀肌肉的动力踝关节假体来产生姿势 预期扰动下的控制机制。 为了实现我的目标，我将测试虚拟系统中残留的对抗肌肉和动力脚踝的能力 分别安装假体。我将使用两个虚拟系统来测试截肢者1)生成不同级别的能力 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，并分析其在绩效上的相关性。然后，我将使用预期的扰动测试范例来 测试截肢者使用电动踝关节假体的直接肌电控制来增强姿势控制的能力。 我将量化动力假肢对整体稳定性的贡献。总体而言，这些结果将提供 更深入地了解残馀拮抗肌作为控制源，并论证 直接肌电控制以恢复假体踝关节的姿势控制机制。非侵入性的 我的工作性质对直接肌电控制的临床翻译也有很大的潜力。

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.