Kalkman Randy K, Briaire Jeroen J, Frijns Johan H M
ENT-department, Leiden University Medical Centre, PO Box 9600, 2300 RC Leiden, The Netherlands.
ENT-department, Leiden University Medical Centre, PO Box 9600, 2300 RC Leiden, The Netherlands; Leiden Institute for Brain and Cognition, PO Box 9600, 2300 RC Leiden, The Netherlands.
Hear Res. 2015 Apr;322:89-98. doi: 10.1016/j.heares.2014.12.004. Epub 2014 Dec 18.
Several multipolar current focussing strategies are examined in a computational model of the implanted human cochlea. The model includes a realistic spatial distribution of cell bodies of the auditory neurons throughout Rosenthal's canal. Simulations are performed of monopolar, (partial) tripolar and phased array stimulation. Excitation patterns, estimated thresholds, electrical dynamic range, excitation density and neural recruitment curves are determined and compared. The main findings are: (I) Current focussing requires electrical field interaction to induce spatially restricted excitation patterns. For perimodiolar electrodes the distance to the neurons is too small to have sufficient electrical field interaction, which results in neural excitation near non-centre contacts. (II) Current focussing only produces spatially restricted excitation patterns when there is little or no excitation occurring in the peripheral processes, either because of geometrical factors or due to neural degeneration. (III) The model predicts that neural recruitment with electrical stimulation is a three-dimensional process; regions of excitation not only expand in apical and basal directions, but also by penetrating deeper into the spiral ganglion. (IV) At equal loudness certain differences between the spatial excitation patterns of various multipoles cannot be simulated in a model containing linearly aligned neurons of identical morphology. Introducing a form of variability in the neurons, such as the spatial distribution of cell bodies in the spiral ganglion used in this study, is therefore essential in the modelling of spread of excitation. This article is part of a Special Issue entitled
在植入式人工耳蜗的计算模型中研究了几种多极电流聚焦策略。该模型包括整个罗森塔尔管中听觉神经元细胞体的真实空间分布。对单极、（部分）三极和相控阵刺激进行了模拟。确定并比较了兴奋模式、估计阈值、电动态范围、兴奋密度和神经募集曲线。主要发现如下：（I）电流聚焦需要电场相互作用来诱导空间受限的兴奋模式。对于蜗轴电极，与神经元的距离太小，无法产生足够的电场相互作用，这导致在非中心触点附近产生神经兴奋。（II）只有当外周突几乎没有或没有兴奋发生时，无论是由于几何因素还是神经退变，电流聚焦才会产生空间受限的兴奋模式。（III）该模型预测，电刺激引起的神经募集是一个三维过程；兴奋区域不仅在顶向和底向扩展，而且通过更深入地穿透螺旋神经节而扩展。（IV）在相同响度下，在包含形态相同的线性排列神经元的模型中，无法模拟各种多极的空间兴奋模式之间的某些差异。因此，在神经元中引入一种变异性形式，例如本研究中使用的螺旋神经节中细胞体的空间分布，对于兴奋传播的建模至关重要。本文是名为<拉斯克奖>的特刊的一部分。
