Three approaches for estimating the elastic modulus of the tympanic membrane

Fay, Jonathan P.; Puria, Sunil; Decraemer, Willem F.; Steele, Charles R.

doi:10.1016/j.jbiomech.2004.08.022

Cited by 110 publications

(94 citation statements)

References 24 publications

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“…They concluded that the pars tensa has strong anisotropy dictated by the local density of fibres and that the Young's modulus may vary by over one order of magnitude from one point to another. Fay et al (2005) considered the multilayer nature of the pars tensa in estimating its Young's modulus. In the human, they estimated the Young's modulus to be from 100 to 300 MPa.…”

Section: Baseline Materials Propertiesmentioning

confidence: 99%

“…The previous gerbil model from our group (Elkhouri et al 2006) used a Young's modulus of 60 MPa for the pars tensa. This was based on the value in common between the estimates of Fay et al (2005) for the posterior section (30-60 MPa) and anterior section (60-90 MPa) of the cat pars tensa. As mentioned earlier (BPars Tensa^section), because the estimates by Fay et al were not based on the full thickness of the pars tensa, the resulting high Young's moduli are not really relevant to isotropic models that model the entire thickness of the pars tensa in a single layer.…”

Section: Model Parametersmentioning

confidence: 99%

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Finite-Element Modelling of the Response of the Gerbil Middle Ear to Sound

Maftoon

Funnell

Daniel

et al. 2015

JARO

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We present a finite-element model of the gerbil middle ear that, using a set of baseline parameters based primarily on a priori estimates from the literature, generates responses that are comparable with responses we measured in vivo using multi-point vibrometry and with those measured by other groups. We investigated the similarity of numerous features (umbo, pars-flaccida and pars-tensa displacement magnitudes, the resonance frequency and break-up frequency, etc.) in the experimental responses with corresponding ones in the model responses, as opposed to simply computing frequency-by-frequency differences between experimental and model responses. The umbo response of the model is within the range of variability seen in the experimental data in terms of the low-frequency (i.e., well below the middle-ear resonance) magnitude and phase, the main resonance frequency and magnitude, and the roll-off slope and irregularities in the response above the resonance frequency, but is somewhat high for frequencies above the resonance frequency. At low frequencies, the ossicular axis of rotation of the model appears to correspond to the anatomical axis but the behaviour is more complex at high frequencies (i.e., above the pars-tensa break-up). The behaviour of the pars tensa in the model is similar to what is observed experimentally in terms of magnitudes, phases, the break-up frequency of the spatial vibration pattern, and the bandwidths of the high-frequency response features. A sensitivity analysis showed that the parameters that have the strongest effects on the model results are the Young's modulus, thickness and density of the pars tensa; the Young's modulus of the stapedial annular ligament; and the Young's modulus and density of the malleus. Displacements of the tympanic membrane and manubrium and the lowfrequency displacement of the stapes did not show large changes when the material properties of the incus, stapes, incudomallear joint, incudostapedial joint, and posterior incudal ligament were changed by ±10 % from their values in the baseline parameter set.

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Section: Baseline Materials Propertiesmentioning

confidence: 99%

Section: Model Parametersmentioning

confidence: 99%

Finite-Element Modelling of the Response of the Gerbil Middle Ear to Sound

Maftoon

Funnell

Daniel

et al. 2015

JARO

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“…The geometry of the eardrum is based on phase-shift moiré topography, a noncontacting optical method that can measure the precise 3D shape of an object Decraemer 1989, 1990). The Young_s modulus of the pars tensa (PT) was set to 60 MPa, based on a recent study by Fay et al (2005), who used theoretical methods to assess Young_s modulus values for cat and human eardrums. For an isotropic cat model, Fay et al (2005) estimated ranges for the Young_s modulus of 30-60 MPa for the posterior region of the PT and 60-90 MPa for the anterior region, so the value of 60 MPa is consistent with our assumption of uniformity.…”

Section: Geometry and Materials Propertiesmentioning

confidence: 99%

“…The Young_s modulus of the pars tensa (PT) was set to 60 MPa, based on a recent study by Fay et al (2005), who used theoretical methods to assess Young_s modulus values for cat and human eardrums. For an isotropic cat model, Fay et al (2005) estimated ranges for the Young_s modulus of 30-60 MPa for the posterior region of the PT and 60-90 MPa for the anterior region, so the value of 60 MPa is consistent with our assumption of uniformity. The overall microstructure of the gerbil PT is similar to that of the human and cat PT, and therefore 60 MPa seems to be a reasonable estimate for the present model.…”

Section: Geometry and Materials Propertiesmentioning

confidence: 99%

Low-Frequency Finite-Element Modeling of the Gerbil Middle Ear

Elkhouri

Liu

Funnell

2006

JARO

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The gerbil is a popular species for experimental middle-ear research. The goal of this study is to develop a 3D finite-element model to quantify the mechanics of the gerbil middle ear at low frequencies (up to about 1 kHz). The 3D reconstruction is based on a magnetic resonance imaging dataset with a voxel size of about 45 mm, and an x-ray micro-CT dataset with a voxel size of about 5.5 mm, supplemented by histological images. The eardrum model is based on moiré shape measurements. Each individual structure in the model was assumed to be homogeneous with isotropic, linear, and elastic material properties derived from a priori estimates in the literature. The behavior of the finite-element model in response to a uniform acoustic pressure on the eardrum of 1 Pa is analyzed. Sensitivity tests are done to evaluate the significance of the various parameters in the finiteelement model. The Young_s modulus and the thickness of the pars tensa have the most significant effect on the load transfer between the eardrum and the ossicles and, along with the Young_s modulus of the pedicle and stapedial annular ligament, on the displacements of the stapes. Overall, the model demonstrates good agreement with low-frequency experimental data. For example, (1) the maximum footplate displacement is about 35 nm; (2) the umbo/stapes displacement ratio is found to be about 3.5; (3) the motion of the stapes is predominantly piston-like; and (4) the displacement pattern of the eardrum shows two points of maximum displacement, one in the posterior region and one in the anterior region. The effects of removing or stiffening the ligaments are comparable to those observed experimentally.

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“…Recently, the full-field TM surface motion was measured using the multi-point LDV measurement (Fay et al 2005;Maftoon et al 2013), timeaverage Rosowski et al 2009) or stroboscopic holographic interferometry ; Del Socorro Hernandez-Montes et al, Cheng et al 2010Cheng et al , 2013Rosowski et al 2011), optical coherence tomography (Djalilian, et al 2008), and scanning laser Doppler vibrometry (Huber et al 2001). The experimental measurements demonstrated that the TM motion pattern was relatively simple with one area of maximal displacement at low frequencies (below 2,000 Hz) dominating.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Modeling Study of Human Tympanic Membrane Motion in the Presence of Middle Ear Liquid

Zhang

Guan

Nakmali

et al. 2014

JARO

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Vibration of the tympanic membrane (TM) has been measured at the umbo using laser Doppler vibrometry and analyzed with finite element (FE) models of the human ear. Recently, full-field TM surface motion has been reported using scanning laser Doppler vibrometry, holographic interferometry, and optical coherence tomography. Technologies for imaging human TM motion have the potential to lead to using a dedicated clinical diagnosis tool for identification of middle ear diseases. However, the effect of middle ear fluid (liquid) on TM surface motion is still not clear. In this study, a scanning laser Doppler vibrometer was used to measure the full-field surface motion of the TM from four human temporal bones. TM displacements were measured under normal and diseasemimicking conditions with different middle ear liquid levels over frequencies ranging from 0.2 to 8 kHz. An FE model of the human ear, including the ear canal, middle ear, and spiral cochlea was used to simulate the motion of the TM in normal and diseasemimicking conditions. The results from both experiments and FE model show that a simple deflection shape with one or two major displacement peak regions of the TM in normal ear was observed at low frequencies (1 kHz and below) while complicated ring-like pattern of the deflection shapes appeared at higher frequencies (4 kHz and above). The liquid in middle ear mainly affected TM deflection shapes at the frequencies higher than 1 kHz.

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Three approaches for estimating the elastic modulus of the tympanic membrane

Cited by 110 publications

References 24 publications

Finite-Element Modelling of the Response of the Gerbil Middle Ear to Sound

Finite-Element Modelling of the Response of the Gerbil Middle Ear to Sound

Low-Frequency Finite-Element Modeling of the Gerbil Middle Ear

Experimental and Modeling Study of Human Tympanic Membrane Motion in the Presence of Middle Ear Liquid

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