Electro-anatomical models of the cochlear implant
Electro-anatomical models of the cochlear implant
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发表时间：
2007
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通讯作者：
Darren M. Whiten
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作者：
Darren M. Whiten
尽管人工耳蜗植入已成为治疗严重至深刻的感官听力损失的患者的护理标准，但受益（交流能力）的单个患者的差异既繁殖又大，并且大多数情况下都无法解释。对这种变化的一种解释是植入耳朵的状态，当在组织病理学上检查时。还显示出由于听力丧失（病因等）和植入引发的病理变化而导致的实质性变化。例如，明显存在电极位置和插入深度的跨门差异。以及差异量的残留螺旋神经节存活率也是如此。纤维组织的形成和电极封装，耳蜗骨化以及对相邻人工耳蜗结构的特质损害。由于在植入的耳朵中发现的组织的复杂几何和电性能。证明病理变异性对神经元激发的影响。并最终在行为表现上。可能需要对周围解剖结构的详细表示。我们的方法是开发能够代表上述患者特定类型的病理变异的植入耳朵的详细的，三维（3D）的电动模型（EAMS）。为了响应电刺激，这些计算模型预测了（1）3D电场的估计值。 （2）神经激活的耳蜗模式，以及（3）从2粒内电极记录的电诱发的复合动作电位（ECAP）。本文重点介绍了三个目标。第一的。两名患者的数百张数字图像提出了两个患者特异性的EAM，两名患者的组织学颞骨骨骼的数字图像试图纳入每个患者的详细病理学。第二。将模型预测与文献的相关报告进行比较，从植入的研究对象中收集的数据以及。最重要的是，从相同的两名患者中收集的档案数据用于得出我们的模型。后者与档案数据（以归档数据的形式，心理物理阈值度量和ECAP记录的形式进行比较），共同显示了模型预测和经验测得的数据之间的有希望的对应关系。第三，通过对模型中解剖学表示的增量调整，研究了各个属性的影响，可能会降低建议益处的机制，并探讨了潜在的干预措施。
While cochlear implantation has become the standard of care in treating patients with severe to profound sensorineural hearing loss, the variation in benefit (communicative ability) individual patients derive from implantation remains both large and, for the most part, unexplained. One explanation for this variation is the status of the implanted ear which, when examined histopathologically. also displays substantial variation due to both the pathogenesis of hearing loss (etiology, etc.) and pathological changes initiated by implantation. For instance, across-patient variation in electrode position and insertion depth is clearly present. as are differential amounts of residual spiral ganglion survival. fibrous tissue formation and electrode encapsulation, cochlear ossification, and idiosyncratic damage to adjacent cochlear structures. Because of the complex geometric and electrical properties of the tissues found in the implanted ear. demonstrating the impact of pathological variability on neuronal excitation. and ultimately on behavioral performance. will likely require a detailed representation of the peripheral anatomy. Our approach has been to develop detailed, three-dimensional (3D) electro-anatomical models (EAMs) of the implanted ear capable of representing the aforementioned patient-specific types of pathological variation. In response to electric stimulation, these computational models predict an estimate of (1) the 3D electric field. (2) the cochleotopic pattern of neural activation, and (3) the electrically-evoked compound action potential (ECAP) recorded from intracochlear electrodes. This thesis focuses on three aims. First. two patient-specific EAMs are formulated from hundreds of digital images of the histologically-sectioned temporal bones of two patients, attempting to incorporate the detailed pathology of each. Second. model predictions are compared to relevant reports from the literature, data collected from a cohort of implanted research subjects, and. most importantly, to archival data collected during life from the same two patients used to derive our models. The latter comparisons to archival data (in the form of intracochlear potential recordings, psychophysical threshold measures, and ECAP recordings) collectively show a promising correspondence between model-predicted and empirically-measured data,. Third, by making incremental adjustments to the anatomical representation in the model, the impact of individual attributes are investigated, mechanisms that may degrade benefit suggested, and potential interventions explored.