Compliance profiles derived from a three-dimensional finite-element model of the basilar membrane

Abstract

A finite-element analysis is used to explore the impact of elastic material properties, boundary conditions, and geometry, including coiling, on the spatial characteristics of the compliance of the unloaded basilar membrane (BM). It is assumed that the arcuate zone is isotropic and the pectinate zone orthotropic, and that the radial component of the effective Young's modulus in the pectinate zone decreases exponentially with distance from base to apex. The results concur with tonotopic characteristics of compliance and neural data. Moreover, whereas the maximum compliance in a radial profile is located close to the boundary between the two zones in the basal region, it shifts to the midpoint of the pectinate zone for the apical BM; the width of the profile also expands. This shift begins near the 1 kHz characteristic place for guinea pig and the 2.4 kHz place for gerbil. Shift and expansion are not observed for linear rather than exponential decrease of the radial component of Young's modulus. This spatial change of the compliance profile leads to the prediction that mechanical excitation in the apical region of the organ of Corti is different to that in the basal region.

Finite element modelling of human auditory periphery including a feed-forward amplification of the cochlea

“…As shown in Figure 3, Young's modulus of the BM decreased along its length. The change in E yy is similar to that derived from the detailed models of the BM (Wada et al 1998;Fleischer and Schmidt 2010). As shown in the paper, the result of our analyses from the model is that the stiffness gradient of BM can properly account for the known frequency place map.…”

Effects of a perilymphatic fistula on the passive vibration response of the basilar membrane

“…The BM consists of collagen fibers embedded in a ground substance and appears to be an anisotropic material (Iurato, 1962;Cabezudo, 1978;Schweitzer et al, 1996;Dreiling et al, 2002). Fleischer et al (2010) reported that spatial variation in the compliance of the BM in both the longitudinal and radial directions is partially caused by the anisotropy. However, the BM is considered to be an isotropic material in this model.…”

“…However, observation of the entire vibration of the BM under physiological conditions is difficult because the bony wall of the cochlea surrounds the BM. To estimate the vibration of the BM under physiological conditions in detail, some theoretical studies have investigated the vibration of the BM using the WentzeleKramerseBrillouin (WKB) method (Steele and Taber, 1979;Lim and Steele, 2002;Yoon et al, 2007) or the finite-element method (Böhnke and Arnold, 1999;Manoussaki and Chadwick, 2000;Parthasarathi et al, 2000;Andoh et al, 2005;Skrodzka, 2005;Ramamoorthy et al, 2007;Meaud and Grosh, 2010;Fleischer et al, 2010).…”

A segmentation method to obtain a complete geometry model of the hearing organ

“…Early cochlea models were designed as a basis for further biomechanical modeling of the hearing process (Givelberg and Brunn, 2003;Fleischer et al, 2010), developments in recent years have seen attempts to use cochlear geometry models for the needs of inner ear surgery; specifically, cochlear implantation (Meshik et al, 2009;Noble et al, 2010). These tendencies allow for a speculation that in the next decade, we could observe geometry cochlear modeling entering clinical practice to obtain individual cochlear models.…”