Andoh Masayoshi, Wada Hiroshi
Department of Bioengineering and Robotics, Tohoku University, Sendai 980-8579, Japan.
J Acoust Soc Am. 2004 Jul;116(1):417-25. doi: 10.1121/1.1763599.
The aim of this study was to predict the characteristics of two types of cochlear pressure waves, so-called fast and slow waves. A two-dimensional finite-element model of the organ of Corti (OC), including fluid-structure interaction with the surrounding lymph fluid, was constructed. The geometry of the OC at the basal turn was determined from morphological measurements of others in the gerbil hemicochlea. As far as mechanical properties of the materials within the OC are concerned, previously determined mechanical properties of portions within the OC were adopted, and unknown mechanical features were determined from the published measurements of static stiffness. Time advance of the fluid-structure scheme was achieved by a staggered approach. Using the model, the magnitude and phase of the fast and slow waves were predicted so as to fit the numerically obtained pressure distribution in the scala tympani with what is known about intracochlear pressure measurement. When the predicted pressure waves were applied to the model, the numerical result of the velocity of the basilar membrane showed good agreement with the experimentally obtained velocity of the basilar membrane documented by others. Thus, the predicted pressure waves appeared to be reliable. Moreover, it was found that the fluid-structure interaction considerably influences the dynamic behavior of the OC at frequencies near the characteristic frequency.
本研究的目的是预测两种类型的耳蜗压力波（即所谓的快波和慢波）的特征。构建了一个柯蒂氏器（OC）的二维有限元模型，其中包括与周围淋巴液的流固相互作用。基底转处OC的几何形状是根据沙鼠半规管中其他人的形态测量确定的。就OC内材料的力学性能而言，采用了先前确定的OC内各部分的力学性能，并根据已发表的静态刚度测量结果确定了未知的力学特征。流固耦合方案的时间推进采用交错方法实现。利用该模型预测了快波和慢波的幅度和相位，以便将数值获得的鼓阶压力分布与已知的耳蜗内压力测量结果相匹配。当将预测的压力波应用于模型时，基底膜速度的数值结果与其他人记录的实验获得的基底膜速度显示出良好的一致性。因此，预测的压力波似乎是可靠的。此外，还发现流固相互作用在特征频率附近的频率下对OC的动态行为有相当大的影响。
