Modeling Electrical Conduction in the Cochlea for Implant Engineering

背景：人工耳蜗是一种复杂的电子设备，用于为聋人提供声音感觉。听力结果是高度可变的，部分原因是植入物接受者之间的解剖差异。目前还没有方法来测量CI产生的详细电压模式；然而，这些信息将有助于理解个体解剖如何影响性能。在这里，我们将使用计算机模拟来计算电压，目的是了解患者特定CI表现的潜在机制。目标：我的长期目标是使用成像和模拟等工程方法来提高CI的性能。这项建议的具体目标是：(1)从图像中开发出解剖学上准确的计算机模型，以计算CI产生的电压，并根据个体解剖量化它们的变化；(2)开发数学方法来估计组织电特性；(3)开发软件，从低分辨率诊断图像自动生成高分辨率模型，以便于对患者的耳朵进行建模；以及(4)开发和应用数学方法，以优化CI设计。科学方法：我和我的团队使用同步加速器(一种直线加速器)和X射线收集了身体耳朵和头部的独特图像，以描绘建模中感兴趣的所有结构。我们将使用这些图像定义计算机模型的详细几何形状，并使用强大的有限元方法模拟电压模式(目标1)。这些模型将被用来研究在过去的建模研究中使用简化的几何图形如何影响计算的电压。对于目标2，将开发一种数学优化方法，以找到每个单独耳朵的“最佳”电属性值。最终，我们希望创建一种易于使用的特定于患者的建模技术，以优化每个患者的CI设置。同步加速器不能用于患者，因此我们将开发计算机视觉软件作为Aim 3的一部分，以从较低分辨率的诊断扫描仪生成高保真模型。我们的同步加速器图像将用于训练提出的算法。最后，在目标4中，我们将开发数学方法和软件来优化CI设计。影响：这项研究的新技术贡献包括(1)生成高保真计算机模型和误差估计的方法，(2)电学特性估计的算法，(3)将我们的建模方法转移到医院常规使用的软件，以及(4)实现最佳CI设计和设置的方法。在这项工作中开发的工具将改善听力结果，并支持CI制造商，其中许多制造商在加拿大有业务。在这个项目中工作的学员将学习先进的成像和计算机模拟工具，这将使他们在几个行业具有很高的就业能力，而不仅仅是听力植入物行业。

CONTEXT: A cochlear implant (CI) is a complex electronic device used to provide the sensation of sound to deaf individuals. Hearing outcomes are highly variable and may arise in part due to anatomical differences amongst implant recipients. There are no methods to measure detailed voltage patterns produced by CIs; however, this information would help in understanding how individual anatomy affects performance. Here, we will use computer simulation to compute voltages with the aim of understanding the mechanisms underlying patient-specific CI performance. OBJECTIVES: My long-term objective is to use engineering methods such as imaging and simulation to improve the performance of CIs. The specific aims of this proposal are to: (1) develop anatomically accurate computer models from images to calculate electrical voltages generated by a CI and quantify how they vary based on individual anatomy, (2) develop mathematical methods to estimate tissue electrical properties, (3) develop software to automatically generate high-resolution models from low-resolution diagnostic images to facilitate modeling of patients' ears, and (4) develop and apply mathematical methods to optimize CI design. SCIENTIFIC APPROACH: My team and I have collected unique images of cadaveric ears and heads using a synchrotron, a type of linear accelerator, and X-rays to depict all structures of interest in modeling. We will define the detailed geometry of computer models using these images and simulate voltage patterns using the powerful finite-element method (Aim 1). These models will be used to investigate how using simplified geometry as in past modeling studies affects computed voltages. For Aim 2, a mathematical optimization method will be developed to find the "best" electrical property values for each individual ear. Ultimately, we would like to create an easy to use, patient-specific modeling technique to optimize CI settings on a per-patient basis. Synchrotrons cannot be used on patients, so we will develop computer vision software as part of Aim 3 to generate high-fidelity models from lower resolution diagnostic scanners. Our synchrotron images will be used to train the proposed algorithms. Lastly, in Aim 4, we will develop mathematical methods and software to optimize CI design. IMPACT: Novel technical contributions of this research include (1) methods to generate high-fidelity computer models along with error estimates, (2) algorithms for electrical property estimation, (3) software to move our modeling methodologies into routine use in hospitals, and (4) methods to achieve optimal CI designs and settings. The tools developed in this work will improve hearing outcomes and support CI manufacturers, many of which have operations in Canada. Trainees working on this project will learn advanced imaging and computer simulation tools that will make them highly employable in several industries, not just the hearing implant industry.