Design of a Smart Prosthetic Liner Controlled by Muscle Activation Feedback

 描述(由申请人提供)： 假体舒适性被认为是下肢截肢者面临的最重要的问题之一，主要取决于残肢/假肢插座界面的适合性和压力。S很好地证实，由于残肢内液体的重新分布和相关的体积变化，插口配合和压力可能会在一天中波动。虽然可以通过穿上或脱下袜子来管理这些变化，但这样做会全局地增加或移除整个肢体的体积，这可能会对局部界面压力产生负面影响。此外，尽管如此，在步态过程中肌肉活动可能会动态地影响残肢的软组织与插口界面之间的压力特性。虽然截肢者的肌肉活动与步态周期有关，但这一活动的功能作用尚不完全清楚。例如，虽然髋部伸肌和屈肌有助于瞬间的产生，但站立时可能需要长时间的活动来稳定关节并保持关节窝的适合性。肌肉激活模式也可以反映对动态眼窝压力的控制，因为肌肉收缩改变了残肢的形状和眼窝压力。然而，目前尚不清楚截肢者残肢的肌电信号与眼窝压力之间的函数关系。这项拟议的研究是一系列调查的第一步，目的是创造一种智能插座接口(衬垫)，可以根据肌电和压力动态调节眼窝内压力。长期目标是设计一种假体，使患者最大限度地舒适，进而最大限度地提高运动能力和与健康相关的生活质量的其他方面。在完成拟议的工作后，我们希望证明：1)在不同的步行速度和步行多分钟的持续时间内，EMG和眼窝内压力之间存在关系；2)这种关系受到眼窝匹配的影响；3)这种关系独立于步态运动学和动力学，以及4)肌电提供关于舒适性的独特信息，并且有可能利用这些信息来操纵眼窝内压力，并在步态过程中最大化舒适性。总体设计理念是仪器化假肢插座/残肢接口(衬垫)，它监控插座内的肌电和压力，以适当地调节行走过程中的压力，从而优化舒适性和功能。我们将在邻近肌电电极放置的位置监测假体接受腔内肌肉表面的压力。当肌肉收缩时，附近肌肉和残端组织的体积也会改变，导致眼窝和肢体之间的局部压力变化。原型设备旨在对这些变化做出反应。作为对肌电的反应，我们将充气/放气已改装到插座并与肌肉对齐的气囊。口袋将使用小型、轻型压缩机充气或放气，这些压缩机将使用简单的车载实时逻辑进行控制。该原型将展示基于残肢肌电控制眼窝内压力的能力。这项拟议的研究旨在为更全面地了解肌电、眼窝压力和舒适性之间的关系奠定基础。创造一种动态界面，改善插座舒适性并降低界面压力，将通过限制日常肢体体积波动、组织破裂、起泡和皮肤发红，改善残肢的整体健康状况。

 DESCRIPTION (provided by applicant): Prosthetic comfort is rated as one of the most important issues faced by lower-limb amputees and is primarily dictated by fit and pressure at the residual limb/prosthetic socket interface. It s well established that socket fit and pressure can fluctuate throughout the day due to redistribution of fluids and associated volumetric changes within the residual limb. While these changes can be managed by donning or doffing socks, doing so will globally add or remove volume to the entire limb, which could negatively affect local interface pressures. Additionally, though, the pressure characteristics between the socket interface and the soft tissue of the residual limb may be dynamically affected by muscle activity during gait. While muscle activity of lower limb amputees is entrained to the gait cycle, the functional roles of this activity are not entirely clear. For example, while hip extensor and flexors muscles aid in moment production, prolonged activity during stance may be needed to stabilize the joint and maintain socket fit. Muscle activation patterns could also reflect control of dynamic socket pressures as muscle contractions alter the shape of the residual limb and socket pressure. However, the functional relationship between electromyography (EMG) signals of the residual limb in lower limb amputees and socket pressure is currently unknown. This proposed study is the initial step in a line of investigations to create an intelligent socket interface (liner) that can modulate intrasocet pressure dynamically based on EMG and pressure. The long-term goal is to design a prosthesis that maximizes patient comfort and in turn movement performance and other associated aspects of health-related quality of life. After completion of the proposed work we expect to demonstrate that: 1) across a variety of walking speeds and across the duration of walking for multiple minutes a relationship exists between EMG and intrasocket pressure; 2) the relationship is affected by socket fit; 3) the relationship is independent of gait kinematics and kinetics, and 4) EMG provides unique information regarding comfort and it is possible to use this information to manipulate intrasocket pressure and maximize comfort during gait. The overall design concept is an instrumented prosthetic socket/residual limb interface (liner) that monitors intrasocket EMG and pressures to appropriately modulate pressures during ambulation so as to optimize comfort and function. We will monitor pressures along the surface of muscles within the prosthetic socket at locations neighboring EMG electrode placement. When the muscle contracts the volume of the nearby muscle and residuum tissue will also change leading to local variations in pressures between the socket and limb. The prototypical device is intended to respond to these changes. In response to EMG, we will inflate/deflate pockets of air that have been retrofit to the socket and aligned with the muscles. Pockets will inflate or deflate using small, lightweight compressors which will be controlled using simple on-board real-time logic. The prototype will demonstrate the ability to manipulate intrasocket pressure based on residual limb EMG. The proposed study is intended to lay the groundwork for a more complete understanding of the relationship between EMG, socket pressure and comfort. Creating a dynamic interface that improves socket comfort and reduces interface pressure would improve overall health of the residual limb by limiting daily limb volume fluctuation, tissue breakdown, blistering and reddening of the skin.