Conformable systems for spatiotemporal decoding of facial strains

许多神经肌肉疾病，如肌萎缩性侧索硬化症（ALS），往往表现自己通过生理变化，包括逐渐丧失的能力，行使精细运动技能和发声可理解的语言。因此，用于连续跟踪面部动态皮肤应变的可预测方法可以为患有这种疾病的个体提供新的交流形式。用于面部变形的体内表征的当前方法涉及肌电图（EMG）、皮肤阻抗测量或相机跟踪。然而，这些通常导致高不确定性或具有庞大的结构，具有与柔软皮肤的高度可见的界面，在日常生活中难以连续使用，特别是对于患有神经肌肉疾病的个体。拟议研究的目的是实现可整合的传感器和系统，可以将体内面部软组织生物力学模式转化为可解释的电信号，以实现新形式的非语言交流。在这个项目中引入的概念，材料，系统设计和表征方法可以提供新的途径，在动态运动过程中的表皮表面的快速，在体内生物运动学评估。这样的系统可以帮助对广泛的神经肌肉状况进行连续的临床监测，其中，由于（i）肌肉运动的时间依赖性改变以及因此由于神经变性进展而导致的可测量的表皮变形，或者（ii）整个医学治疗过程中的响应，预期会发生变化。拟议的跨学科项目将与教育和推广活动相结合，包括关于适形传感器微制造的跨学科课程，以及为从K-12到研究生水平的代表性不足的学生开发低功耗，计算轻的医学传感范例。软组织生物运动学的精确测量，例如面部变形期间的皮肤应变，可以用于计算识别不同的面部运动，从而为缺乏说话能力或与传统电子通信接口交互的患者提供非语言通信。然而，现有的非语言通信系统不适合用于身体的曲线区域，例如面部。一个可广泛部署的系统，实时检测面部运动，结合使用低成本的材料，易于制造的过程中，和一个无缝的管道制造，测试和验证，提供了前所未有的潜力，临床上可实现的非语言通信技术。拟议的研究的主要目标是引入一组材料，设备设计，制造步骤，理论计算，模拟和验证协议，实现强大的，机械自适应的，可预测的，视觉上不可见的时空表皮应变和解码不同的面部变形签名通过使用由压电薄膜组成的顺应性基板上的顺应性设备的体内监测。在项目过程中将解决的挑战包括：1）开发一种适应性面部代码外推传感器（cFaCES），2）三维数字图像相关（3D-DIC）用于动态变形下软组织的时空评估，以及3）在各种面部变形期间对健康和肌萎缩侧索硬化（ALS）受试者进行体内实时解码（RTD）。拟议的工作将建立在PI的跨学科的专业知识和经验，压电，微加工生物医学设备和适应系统。拟议的系统将引入一种新的设备设计和微加工策略，沿着，一个框架和先进的算法，这将是一个关键的推动者，重建时空准确的应变图，为任何人体软组织。这一奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。

Many neuromuscular disorders, such as amyotrophic lateral sclerosis (ALS), often manifest themselves through physiological changes including gradual loss of the ability to exercise fine motor skills and to vocalize intelligible speech. Predictable methods for continuous tracking of dynamic skin strain on the face, therefore, can enable new forms of communication for individuals with such disorders. Present methods for in vivo characterization of facial deformations involve electromyography (EMG), skin impedance measurements, or camera tracking. Yet these typically result in high uncertainties or have bulky structures with highly visible interfaces to soft skin, presenting difficulty for continuous use in daily life, especially for individuals with neuromuscular disorders. The aim of the proposed research is to realize conformable sensors and systems that can translate patterns of facial soft tissue biomechanics in vivo into interpretable electrical signals to enable new forms of non-verbal communication. The concepts, materials, system design and characterization methods to be introduced in this project can offer new routes for rapid, in vivo biokinematic assessment of epidermal surfaces during dynamic movements. Such systems can help for continuous clinical monitoring of a wide range of neuromuscular conditions, where variations are anticipated due either to (i) time-dependent alterations in muscle movements, and thus measurable epidermal deformations due to neurodegeneration progression, or (ii) a response throughout medical therapy. The proposed interdisciplinary project will be integrated with educational and outreach activities, including interdisciplinary classes on the microfabrication of conformable sensors and the development of lower-power, computationally light paradigms for medical sensing for underrepresented students all the way from K-12 to graduate levels.Precise measurements of soft tissue biokinematics, such as skin strain during facial deformations, can be used to computationally recognize distinct facial motions, and thus facilitate nonverbal communication for patients who lack the ability to speak or interact with traditional electronic communication interfaces. However, existing nonverbal communication systems are unsuitable for use on curvilinear regions of the body, such as the face. A widely deployable system for real-time detection of facial motions, when combined with the use of low-cost materials, easily manufacturable processes, and a seamless pipeline for fabrication, testing, and validation, offers unprecedented potential for clinically realizable nonverbal communication technologies. The primary goal of the proposed research is to introduce a set of materials, device designs, fabrication steps, theoretical calculations, simulations, and validation protocols that realize robust, mechanically-adaptive, predictable, and visually-invisible in vivo monitoring of spatiotemporal epidermal strains and decoding of distinct facial deformation signatures through the use of conformable devices comprised of piezoelectric thin films on compliant substrates. The challenges that will be addressed during the course of the project include: 1) Development of a conformable Facial Code Extrapolation Sensor (cFaCES), 2) Three-Dimensional Digital Image Correlation (3D-DIC) for spatiotemporal assessment of soft tissues under dynamic deformations, and 3) In vivo Real-Time Decoding (RTD) on both healthy and amyotrophic lateral sclerosis (ALS) subjects during various facial deformations. The proposed work will build upon the PI's interdisciplinary expertise and experience in piezoelectric, microfabricated biomedical devices and conformable systems. The proposed system will introduce a novel device design and microfabrication strategy, along with a framework and advanced algorithms that will be a key enabler to reconstruct spatiotemporally accurate strain maps for any human body soft tissue.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.