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A Theoretical Study Into The Effect Of Load On The Tympanic Membrane And Middle Ear Using Finite Element Analysis
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Book Synopsis A Theoretical Study Into the Effect of Load on the Tympanic Membrane and Middle Ear Using Finite Element Analysis by :
Download or read book A Theoretical Study Into the Effect of Load on the Tympanic Membrane and Middle Ear Using Finite Element Analysis written by and published by . This book was released on 1993 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A Theoretical Study Into the Effect of Load on the Human Eardrum and Middle Ear Using Finite Element Analysis by : Tristram Hugh John Lesser
Download or read book A Theoretical Study Into the Effect of Load on the Human Eardrum and Middle Ear Using Finite Element Analysis written by Tristram Hugh John Lesser and published by . This book was released on 1993 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Finite Element Simulation of External Ear Sound Fields for the Optimization of Eardrum-related Measurements by : Sebastian Schmidt
Download or read book Finite Element Simulation of External Ear Sound Fields for the Optimization of Eardrum-related Measurements written by Sebastian Schmidt and published by Logos Verlag Berlin GmbH. This book was released on 2009-08-31 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: The sound pressure pT at the human eardrum has essential advantages as reference signal in audiological and psychoacoustical experiments. Unfortunately, precise pressure measurements very close to the tympanic membrane are difficult. In practice, the microphone has to be positioned at a certain distance from the eardrum. The measured pressure then has to be transformed to the eardrum. As a "classical" approach for the estimation of the necessary transfer function, an acoustical network model of the ear canal is developed from geometrical data of the canal (cross-sectional area function) which is in turn determined from measurements of its acoustical input impedance. Such methods, however, do not provide robust results. In this thesis, the concept of one-dimensional models of the ear canal is examined to find the origin of these errors. For this purpose, the sound field at the human external ear was analyzed using finite element models. Inside the canal, irregular three-dimensional structures occur that cannot be modelled accurately using classical one-dimensional network concepts. Upon these findings, an accurate, efficient and highly feasible method for the estimation of pT was developed. Equal-loudness level contours with reference to the eardrum pressure that were measured as pilot application of the new method are presented.
Book Synopsis Index to Theses with Abstracts Accepted for Higher Degrees by the Universities of Great Britain and Ireland and the Council for National Academic Awards by :
Download or read book Index to Theses with Abstracts Accepted for Higher Degrees by the Universities of Great Britain and Ireland and the Council for National Academic Awards written by and published by . This book was released on 1995 with total page 1200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A Theoretical Study of Eardrum Vibrations Using the Finite-element Method by : William Robert John Funnell
Download or read book A Theoretical Study of Eardrum Vibrations Using the Finite-element Method written by William Robert John Funnell and published by 1975.. This book was released on 1975 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Middle Ear Mechanics In Research And Otology - Proceedings Of The 3rd Symposium by : Kiyofumi Gyo
Download or read book Middle Ear Mechanics In Research And Otology - Proceedings Of The 3rd Symposium written by Kiyofumi Gyo and published by World Scientific. This book was released on 2004-07-26 with total page 457 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book aims to facilitate the exchange of ideas between otosurgeons and engineers on common topics such as middle ear function, tympanoplasty, implantable hearing devices and ear prostheses. Due to recent advances in technology, gene-therapy and tissue-engineering procedures will also be important issues in the treatment of middle ear disease.
Book Synopsis Finite-element Models Related to Widebrand Tympanometry in Newborns by : Hamid Motallebzadeh
Download or read book Finite-element Models Related to Widebrand Tympanometry in Newborns written by Hamid Motallebzadeh and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Early detection of hearing loss accompanied by appropriate early intervention is important in order to avoid problems associated with delayed language development, with its impact on daily communication, educational achievement, psychosocial development and later employment opportunities. Current screening methods are associated with high false-positive rates, which can be attributed to transient conditions in the external ear and middle ear in the first 48 hours post partum. Tympanometry (input acoustic admittance measurement in the presence of a range of static pressures) is a promising tool for evaluating the status of the middle ear in newborns.Tympanometry involves both non-linear responses and viscoelastic (time-dependent) effects, and the tympanic membrane contributes to the overall response more than other middle-ear components do. We have therefore developed a non-linear viscoelastic model based on experimental data reported in the literature for excised strips of tympanic membrane. The constitutive equation of this model is a convolution integral, composed of the Ogden hyperelastic model and the exponential time-dependent function of the Prony series. The model was validated by reproducing the measured hysteresis effect with a single set of parameters. The newborn ear is anatomically very different from the adult one, resulting in a different input admittance than in adults. We have developed a finite-element model to investigate the admittance responses of the ear canal and middle ear in newborns for frequencies up to 2 kHz. The model was validated by comparison with two sets of clinical data and provides quantitative insight into the separate contributions of the outer and middle ear. The results suggest that admittance measurements could provide more information about the condition of the middle-ear if made at multiple frequencies around its resonance (around 1.8 kHz).Wideband stimuli are used to extend admittance measurements to higher frequencies. Taking into account the fluid-structure interaction (FSI) between the air inside the canal and middle-ear cavity and the structure of the ear, we have extended the frequency range of our newborn model up to 10 kHz. The first and second standing-wave modes in the canal were observed at 7.2 and 9.6 kHz, respectively, and the resonance of the middle-ear cavity was identified at 6.1 kHz. The model was validated by comparison with two sets of clinical data and provides interpretations for features that exist in the clinical data but whose significance was not clear.Our numerical models of the non-linear viscoelastic tympanic membrane and of the admittance responses of the newborn ear provide quantitative insight into the mechanics of the ear and establish a groundwork for the clinical application and interpretation of admittance measurements in newborns." --
Book Synopsis Finite-element Modelling of Tympanic-membrane Vibrations Under Quasi-static Pressurization by : Sahar Choukir
Download or read book Finite-element Modelling of Tympanic-membrane Vibrations Under Quasi-static Pressurization written by Sahar Choukir and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Early detection of hearing loss is important so it can be addressed in a timely manner. Current newborn hearing screening methods produce high false-positive rates which are attributed to transient conditions in the external and middle ear in the first 48 hours after birth. Tympanometry (acoustical input admittance measurement in the presence of a range of quasi-static pressures) is a promising tool for characterizing middle-ear status in newborns but their response to tympanometry is not well understood. Tympanometry involves large, nonlinear deformations; viscoelastic (time-dependent) effects; and complex dynamic responses. The goal of this study is to combine these three features in a dynamic nonlinear viscoelastic model. The constitutive equation of this model is a convolution integral composed of a Mooney-Rivlin hyperelastic model and an exponential time-dependent Prony series with six time constants. Material properties are taken from previous measurements and estimates. The tympanic membrane contributes to the overall response more than other middle-ear components do and those other components are greatly simplified in this model. The tympanic membrane is assumed to be homogeneous and nearly incompressible. The loading conditions included low-amplitude sound pressures; high quasi-static pressures; and combinations of high quasi-static pressures with low- amplitude sound pressures, corresponding to those involved in tympanometry. Simulations were performed with two different finite-element solvers and we report simulated displacements and vibrations in the frequency and time domains for the different loading conditions. Results from the two finite-element solvers were compared and were similar. The simulation results were compared with measured data from experimental animals. In response to high quasi-static pressures, the model replicates the asymmetrical effects of positive and negative pressures on the displacement; the hysteresis of the displacement; and the frequency dependence of the hysteresis. The model also replicates the differences between the peak-admittance magnitudes and the pressures at which they occur for low-amplitude vibrations during negative and positive sweeps of high quasi-static pressures. Our dynamic nonlinear viscoelastic model of the middle ear permits quantitative insights into the middle ear's response to different loading conditions and will help to establish improved applications of tympanometric measurements in newborns." --
Book Synopsis Dissertation Abstracts International by :
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2004 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Mechanics of Biological Systems and Materials, Volume 6 by : Srinivasan Arjun Tekalur
Download or read book Mechanics of Biological Systems and Materials, Volume 6 written by Srinivasan Arjun Tekalur and published by Springer. This book was released on 2015-10-29 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: 5thInternational Symposium on the Mechanics of Biological Systems and Materials, Volume 6 of the Proceedings of the 2015SEM Annual Conference& Exposition on Experimental and Applied Mechanics, the sixth volume of nine from the Conference, brings together contributions to this important area of research and engineering. The collection presents early findings and case studies on a wide range of areas, including: Soft Tissues Mechanics Bio-Engineering and Biomechanics Natural Materials & Bio-Inspiration Novel Techniques and Experiments in Biomechanics Tissue Engineering Cells Mechanics
Book Synopsis Finite-element Modelling of Middle-ear Vibrations Under Quasi-static Pressurization by : Dongfang Qian
Download or read book Finite-element Modelling of Middle-ear Vibrations Under Quasi-static Pressurization written by Dongfang Qian and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Early identification of hearing loss is important because if untreated it can lead to delayed language development and other difficulties. Current tools for newborn hearing screening are subject to excessively high false-positive rates. Tympanometry is a promising tool for improving screening tests by evaluating the condition of the middle ear, but it is poorly understood in newborns. Tympanometry involves large deformations, non-linear responses, viscoelastic (time-dependent) effects, and complex dynamic responses, which make it hard to model. A previous gerbil finite-element model developed in our lab was the first numerical simulation of tympanometry involving the simultaneous application of large quasi-static pressures and small sound pressures, and it succeeded in replicating some features of tympanometry. However, the model involved over-simplified anatomical details of the ossicles to reduce the computational cost. The goal of this study was to improve the model by adding a representation of the incudostapedial joint and its surrounding structures.The model employed a quasi-linear visco-hyperelastic model with several time constants in a Prony series. Material properties were taken from previous models and publications. The tympanic membrane was assumed to be homogeneous and nearly incompressible. The loads, combining high quasi-static pressures with low-amplitude sound pressures, both low-frequency pure tones and wideband chirps, reflected the conditions in tympanometry. The model was verified against our previous models, and validated against data from the literature and our recent laser vibrometry data for the pressurized gerbil middle ear. The model demonstrated experimentally and clinically observed features, including hysteresis and the asymmetry in the vibration amplitude between positive and negative static pressures.This numerical model will help us gain insight into how the middle ear responds to different stimuli and thus open up new approaches to the interpretation of tympanometric measurements"--
Book Synopsis Experimental and Modelling Study of Gerbil Middle Ear by : Nima Maftoon
Download or read book Experimental and Modelling Study of Gerbil Middle Ear written by Nima Maftoon and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "This thesis presents in vivo experimental measurements of vibrations on the surgically exposed tympanic membrane (TM) in the gerbil and a finite-element model of the gerbil middle ear. The TM is composed of the pars tensa and pars flaccida and is connected to the middle-ear bones via the manubrium of the malleus. Measurements were done on the pars flaccida and at several points along the manubrium and on the pars tensa using a laser Doppler vibrometer. Measurements were first done with a closed middle-ear cavity. The manubrial points show an increasing displacement magnitude from the lateral process toward the umbo, with the apparent axis of rotation shifting at high frequencies. Above 5 kHz, phase differences between points along the manubrium may indicate flexing in the manubrium. The simple low-frequency vibration pattern of the pars tensa breaks up at between 1.8 and 2.8 kHz.The effects of progressive opening of the middle-ear cavity were then explored. In all responses, opening the cavity causes an increase in the low-frequency magnitude and a shift of the main middle-ear resonance to lower frequencies, and introduces an antiresonance. However, opening the cavity has little or no effect on either the mode of vibration of the manubrium or the breakup frequency of the pars tensa. An identification method was developed for eliminating the effect of the antiresonance. It was validated and then applied to manubrial and pars-tensa responses. The finite-element model developed in this study uses a set of baseline parameters based primarily on a priori estimates from the literature. Responses from the model were validated against our measurements and against measurements from other groups. The responses of the model are mostly within the range of variability seen in the experimental data. A sensitivity analysis ranked the parameters of the model based on their effects on the model results." --
Book Synopsis Finite-element Modelling of the Human Middle Ear Based on X-ray Micro-computed Tomography and Doppler Optical Coherence Tomography in the Same Ear by : Xuan Wang
Download or read book Finite-element Modelling of the Human Middle Ear Based on X-ray Micro-computed Tomography and Doppler Optical Coherence Tomography in the Same Ear written by Xuan Wang and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "The middle ear plays a critical role in transferring sound into the inner ear. The vibration patterns of the tympanic membrane (TM) and ossicles have been investigated by many groups but, particularly at high frequencies, are still not well understood. Computational modelling of the middle ear offers a pathway toward a better understanding of the mechanical function of these structures. The tuning and validation of such models require accurate anatomical and mechanical experimental data, but such data usually come from populations of ears and little is known about how differences in individual anatomy and material properties affect middle-ear function. In this study we created a finite-element (FE) numerical model of a middle ear and validated it against vibration measurements from the same ear.A real-time phase-sensitive Doppler optical coherence tomography (OCT) system was used to measure the vibrations of both the TM and the ossicles of a human temporal bone at a stimulation frequency of 500 Hz. The measured vibration pattern of the TM showed a maximal displacement in the posterior region and a smaller maximum in the anterior region. The experimental data also showed smaller displacements on the ossicles, while the cochlear promontory appeared immobile as expected.A 3-D X-ray micro-computed tomography (microCT) scan was acquired for the same ear. A FE model of the middle ear was built using a combination of locally developed and other free and open-source software. The geometry was based on semi-automatic segmentation of the microCT images, and material properties were based on previous studies. A sensitivity analysis was performed to analyze the relative importance of the various parameters. The Doppler OCT images, masked by B-mode OCT images to reduce noise, were also segmented and the resulting 3-D model was transformed to Cartesian coordinates and aligned with the microCT-based model.Two FE solvers (Code_Aster and SAP IV) were used as part of the verification process. The simulated vibration patterns from the different solvers were compared with the measured Doppler-mode OCT velocity data and with data from the literature. The simulation results match well with the shape of the measured vibration pattern of the TM at 500 Hz. Co-registration of OCT and microCT for individual ears is a viable approach for building and validating FE models. If extended to clinical CT scans, this process could lead to patient-specific models and improved diagnosis of pathological changes in the middle ear. The process of creating FE models for the middle ear would need to be streamlined for clinical applications." --
Book Synopsis A Study of Middle Ear Biomechanics Using the Finite Element Method by : Daniel John Kelly
Download or read book A Study of Middle Ear Biomechanics Using the Finite Element Method written by Daniel John Kelly and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Biomechanics of Hearing by : John J. Rosowski
Download or read book Biomechanics of Hearing written by John J. Rosowski and published by . This book was released on 1999 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: How does the structure of the ear define normal auditory function and how do pathologically and surgically induced changes in the ear structure change hearing? This volume presents the results of the Euromech Colloquium on 'Biomechanics of Hearing'. Attended by experts - engineers, physicists, audiologists - active in different fields of modern measurement techniques, modeling and simulation and microsurgery with applications to hearing. Common themes were the description of auditory function on the basis of mathematical models of the middle and inner ear and identification, i.e. the use of measurements of middle and inner ear function to evaluate the parameters of the suggested models for normal, pathological and reconstructed ears and to refine them in their structure. The collected papers point out the positive accomplishments that can be derived from quantitative multidisciplinary approaches to hearing science. This volume is indispensable reading for audiologists, physicians and hearing scientists interested in the mechanics and acoustics of the auditory periphery.
Book Synopsis A Finite-Element Model for Evaluation of Middle Ear Mechanics by :
Download or read book A Finite-Element Model for Evaluation of Middle Ear Mechanics written by and published by . This book was released on 2001 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A computer model of the middle ear, ossicular chain and eardrum was established using the finite-element method. A preliminary comparison of the model with measurements made in human-cadaver ears shows that the model is in approximate agreement with the form of the middle ear function. The computer model will be used for implant design.
Book Synopsis Analysis of Tympanic Membrane Mechanics Before and After Surgical Reconstruction Using the Finite Element Method by : Alex Lyons
Download or read book Analysis of Tympanic Membrane Mechanics Before and After Surgical Reconstruction Using the Finite Element Method written by Alex Lyons and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
