FINITE ELEMENT ANALYSIS OF THE EFFECT OF ACTUATOR COUPLING CONDITIONS ON ROUND WINDOW STIMULATION

2015 ◽  
Vol 15 (04) ◽  
pp. 1550048 ◽  
Author(s):  
JIABIN TIAN ◽  
XINSHENG HUANG ◽  
ZHUSHI RAO ◽  
NA TA ◽  
LIFU XU
Keyword(s):  
Finite Element ◽  
Middle Ear ◽  
Round Window ◽  
Round Window Membrane ◽  
Fe Model ◽  
Ear Canal ◽  
Sound Stimulation ◽  
Fe Method ◽  
Coupling Conditions ◽  
Intracochlear Pressure

The finite element (FE) method was used to analyze the effect of coupling conditions between the actuator and the round window membrane (RWM) on the performance of round window (RW) stimulation. A FE model of the human ear consisting of the external ear canal, middle ear and cochlea was firstly developed, and then validation of this model was accomplished through comparison between analytical results and experimental data in the literature. Intracochlear pressure were derived from the model under normal forward sound stimulation and reverse RW stimulation. The equivalent sound pressure of RW stimulation was then calculated via comparing the differential intracochlear pressure produced by the actuator and normal ear canal sound stimulus. The actuator was simulated as a floating mass and placed onto the middle ear cavity side of RWM. Two aspects about the actuator coupling conditions were considered in this study: (1) the cross-section area of the actuator relative to the RWM; (2) the coupling layer between the actuator and the RWM. The results show that smaller actuator size can improve the implant performance of RW stimulation, and size requirements of the actuator can also be reduced by introducing a coupling layer between the actuator and RWM, which will benefit the manufacture of the actuator.

scholarly journals Evaluation of Round Window Stimulation Performance in Otosclerosis Using Finite Element Modeling

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Shanguo Yang ◽  
Dan Xu ◽  
Xiaole Liu
Keyword(s):  
Finite Element ◽  
Middle Ear ◽  
Bone Growth ◽  
Round Window ◽  
Element Model ◽  
Annular Ligament ◽  
Fe Model ◽  
Sound Stimulation ◽  
Partial Fixation ◽  
Human Ear

Round window (RW) stimulation is a new type of middle ear implant’s application for treating patients with middle ear disease, such as otosclerosis. However, clinical outcomes show a substantial degree of variability. One source of variability is the variation in the material properties of the ear components caused by the disease. To investigate the influence of the otosclerosis on the performance of the RW stimulation, a human ear finite element model including middle ear and cochlea was established based on a set of microcomputerized tomography section images of a human temporal bone. Three characteristic changes of the otosclerosis in the auditory system were simulated in the FE model: stapedial annular ligament stiffness enlargement, stapedial abnormal bone growth, and partial fixation of the malleus. The FE model was verified by comparing the model-predicted results with published experimental measurements. The equivalent sound pressure (ESP) of RW stimulation was calculated via comparing the differential intracochlear pressure produced by the RW stimulation and the normal eardrum sound stimulation. The results show that the increase of stapedial annular ligament and partial fixation of the malleus decreases RW stimulation’s ESP prominently at lower frequencies. In contrast, the stapedial abnormal bone growth deteriorates RW stimulation’s ESP severely at higher frequencies.

3D Finite Element Modeling of Blast Wave Transmission From the External Ear to a Spiral Cochlea

2021 ◽  
Author(s):  
Marcus Brown ◽  
John Bradshaw ◽  
Rong Z. Gan
Keyword(s):  
Finite Element ◽  
Middle Ear ◽  
Basilar Membrane ◽  
Transverse Motion ◽  
Fe Model ◽  
Ear Canal ◽  
Blast Overpressure ◽  
Stapes Footplate ◽  
Human Ear ◽  
Temporal Bones

Abstract Blast-induced injuries affect the health of veterans, in which the auditory system is often damaged, and blast-induced auditory damage to the cochlea is difficult to quantify. A recent study modeled blast overpressure (BOP) transmission throughout the ear utilizing a straight, two-chambered cochlea, but the spiral cochlea's response to blast exposure has yet to be investigated. In this study, we utilized a human ear finite element (FE) model with a spiraled, two-chambered cochlea to simulate the response of the anatomical structural cochlea to BOP exposure. The FE model included an ear canal, middle ear, and two and half turns of two-chambered cochlea and simulated a BOP from the ear canal entrance to the spiral cochlea in a transient analysis utilizing fluid-structure interfaces. The model's middle ear was validated with experimental pressure measurements from the outer and middle ear of human temporal bones. The results showed high stapes footplate displacements up to 28.5µm resulting in high intracochlear pressures and basilar membrane (BM) displacements up to 43.2µm from a BOP input of 30.7kPa. The cochlea's spiral shape caused asymmetric pressure distributions as high as 4kPa across the cochlea's width and higher BM transverse motion than that observed in a similar straight cochlea model. The developed spiral cochlea model provides an advancement from the straight cochlea model to increase the understanding of cochlear mechanics during blast and progresses towards a model able to predict potential hearing loss after blast.

scholarly journals The Influence of Piezoelectric Transducer Stimulating Sites on the Performance of Implantable Middle Ear Hearing Devices: A Numerical Analysis

Micromachines ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 782 ◽  
Author(s):  
Liu ◽  
Zhao ◽  
Yang ◽  
Rao
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Middle Ear ◽  
Hearing Aids ◽  
Piezoelectric Transducer ◽  
Basilar Membrane ◽  
Round Window ◽  
Element Model ◽  
Round Window Membrane ◽  
Hearing Devices

To overcome the inherent deficiencies of hearing aids, implantable middle ear hearing devices (IMEHDs) have emerged as a new treatment for hearing loss. However, clinical results show that the IMEHD performance varies with its transducer’s stimulating site. To numerically analyze the influence of the piezoelectric transducer’s stimulating sites on its hearing compensation performance, we constructed a human ear finite element model and confirmed its validity. Based on this finite element model, the displacement stimulation, which simulates the piezoelectric transducer’s stimulation, was applied to the umbo, the incus long process, the incus body, the stapes, and the round window membrane, respectively. Then, the stimulating site’s effect of the piezoelectric transducer was analyzed by comparing the corresponding displacements of the basilar membrane. Besides, the stimulating site’s sensitivity to the direction of excitation was also studied. The result of the finite element analysis shows that stimulating the incus body is least efficient for the piezoelectric transducer. Meanwhile, stimulating the round window membrane or the stapes generates a higher basilar membrane displacement than stimulating the eardrum or the incus long process. However, the performance of these two ideal sites’ stimulation is sensitive to the changes in the excitation’s direction. Thus, the round window membrane and the stapes is the ideal stimulating sites for the piezoelectric transducer regarding the driving efficiency. The direction of the excitation should be guaranteed for these ideal sites.

Finite Element Modeling of Sound Transmission Based on Micro-Computer Tomography for Human Ear

2013 ◽  
Vol 419 ◽  
pp. 593-601
Author(s):  
Jia Bin Tian ◽  
Na Ta ◽  
Zhu Shi Rao ◽  
Li Fu Xu ◽  
Xin Sheng Huang
Keyword(s):  
Finite Element ◽  
Middle Ear ◽  
Computer Tomography ◽  
Physiological Data ◽  
Fe Model ◽  
External Ear ◽  
Ear Canal ◽  
External Ear Canal ◽  
Hearing Devices ◽  
Human Ear

An accurate finite element (FE) model of the human ear can help in understanding the physiological mechanismof human ear and facilitate the design of implantable hearing devices. In this paper,a FE modelof the human ear consisting of the external ear canal, middle ear, and cochlea was developed. The geometry of the external ear canal and middle ear model was based on a fresh specimen of human temporal boneviamicro-computer tomography imaging. A harmonic sound pressure of 90 dB SPL was applied in the ear canal and the multi-field coupled FE analysis was conductedamong the ear canal air, cochlea fluid, and middle ear and cochlea structures. The results were compared with the established physiological data. The satisfactory agreements between the model and published experimental measurementsindicate the middle ear and cochlea functions can be well simulated and further application in terms of human ear can be achieved by the model.

scholarly journals Low-Frequency Sound Pressure and Transtympanic Endoscopy of the Middle Ear in Assessment of “Spontaneous” Perilymphatic Fistula

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Ilmari Pyykkö ◽  
Ziane Selmani ◽  
Jing Zou
Keyword(s):  
Middle Ear ◽  
Round Window ◽  
Low Frequency ◽  
Oval Window ◽  
Round Window Membrane ◽  
Outer Diameter ◽  
Sound Stimulation ◽  
Perilymphatic Fistula ◽  
Frequency Sound ◽  
First Choice

This study was designed to verify an eventual perilymphatic fistula (PLF) in 264 patients with sensorineural hearing loss (SNHL) and/or vertigo. The patients were exposed to a low-frequency sound stimulation (LFS) on posturography to objectively test Tullio’s phenomenon and Hennebert's sign. Endoscopes with 5 degree and 25 degree of visual angle and an outer diameter of 1.7 mm were used. The round window niche, with its foldings, oval window with stapes superstructure, a part of the facial recess and the area in the fissula ante fenestram were examined and video recorded. In one patient, we endoscopically verified a fistula in the round window membrane (resulting from a diving accident) that was covered with a fibrinous layer. In 4 cases, there was abnormal mucosal shining in the round window but without PLF. In 7 cases, the tympanic cavity could not be visualized because of the adhesive middle ear process, the abnormal anatomy, or the prominent exostoses of the ear canal prohibited vision. In 34 patients, LFS provoked unsteadiness on posturography without PLF. In 6 cases, a postoperative middle ear infection was recorded. No permanent tympanic membrane perforation occurred. It is unlikely that disease entity of “spontaneous PLF” exists. Tympanoscopy should be regarded as the first choice when a PLF is suspected.

FINITE ELEMENT MODELING OF THE HUMAN COCHLEA USING FLUID–STRUCTURE INTERACTION METHOD

2015 ◽  
Vol 15 (03) ◽  
pp. 1550039 ◽  
Author(s):  
LIFU XU ◽  
XINSHENG HUANG ◽  
NA TA ◽  
ZHUSHI RAO ◽  
JIABIN TIAN
Keyword(s):  
Finite Element ◽  
Transfer Functions ◽  
Basilar Membrane ◽  
Fluid Structure Interaction ◽  
Fe Model ◽  
Ear Canal ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Human Cochlea ◽  
Intracochlear Pressure

In this paper, a 3D finite element (FE) model of human cochlea is developed. This passive model includes the structure of oval window, round window, basilar membrane (BM) and cochlear duct which is filled with fluid. Orthotropic material property of the BM is varying along its length. The fluid–structure interaction (FSI) method is used to compute the responses in the cochlea. In particular, the viscous fluid element is adopted for the first time in the cochlear FE model, so that the effects of shear viscosity in the fluid are considered. Results on the cochlear impedance, BM response and intracochlear pressure are obtained. The intracochlear pressure includes the scala vestibule and scala tympani pressure are extracted and used to calculate the transfer functions from equivalent ear canal pressures to scala pressures. The reasonable agreements between the model results and the experimental data in the literature prove the validity of the cochlear model for simulating sound transmission in the cochlea. Moreover, this model predicted the transfer function from equivalent ear canal pressures to scala pressures which is the input to the cochlear partition.

Finite Element Model of Human Cochlea Considering of the Helicotrema Size

2013 ◽  
Vol 456 ◽  
pp. 576-581 ◽  
Author(s):  
Li Fu Xu ◽  
Na Ta ◽  
Zhu Shi Rao ◽  
Jia Bin Tian
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Basilar Membrane ◽  
Round Window ◽  
Element Model ◽  
Oval Window ◽  
Fe Model ◽  
Cochlear Duct ◽  
Human Cochlea ◽  
Set Up

A 2-D finite element model of human cochlea is established in this paper. This model includes the structure of oval window, round window, basilar membrane and cochlear duct which is filled with fluid. The basilar membrane responses are calculated with sound input on the oval window membrane. In order to study the effects of helicotrema on basilar membrane response, three different helicotrema dimensions are set up in the FE model. A two-way fluid-structure interaction numerical method is used to compute the responses in the cochlea. The influence of the helicotrema is acquired and the frequency selectivity of the basilar membrane motion along the cochlear duct is predicted. These results agree with the experiments and indicate much better results are obtained with appropriate helicotrema size.

Role of the Round Window Membrane in Middle Ear Immune Responses

1988 ◽  
Vol 105 (sup457) ◽  
pp. 139-143 ◽  
Author(s):  
E. M. Keithley ◽  
A. F. Ryan ◽  
J. P. Harris
Keyword(s):  
Immune Responses ◽  
Middle Ear ◽  
Round Window ◽  
Round Window Membrane

scholarly journals 3D Finite Element Model Simulating the Behaviour of Filling Soils Used to Set Up a New Placement Method for Separate Sewer Systems

2019 ◽  
Vol 8 (3) ◽  
pp. 87-98
Author(s):  
Alaa Abbas ◽  
Felicite Ruddock ◽  
Rafid Alkhaddar ◽  
Glynn Rothwell ◽  
Iacopo Carnacina ◽  
...  
Keyword(s):  
Finite Element ◽  
Soil Properties ◽  
Model Simulation ◽  
New Method ◽  
Traffic Load ◽  
Scale Model ◽  
Fe Model ◽  
Fe Method ◽  
Buried Pipes ◽  
The Impact

The use of a finite element (FE) method and selection of the appropriate model to simulate soil elastoplastic behaviour has confirmed the importance and sensitivity of the soil properties on the accuracy when compared with experimental data. The properties of the filling soil play a significant role in determining levels of deformation and displacement of both the soil and subterranean structures when using the FE model simulation. This paper investigates the impact of the traffic load on the filling soil deformation when using the traditional method, one pipe in a trench, and a new method, two pipes in a single trench one over the other, for setting up a separate sewer system. The interaction between the buried pipes and the filling soils has been simulated using an elastoplastic FE model. A modified Drucker–Prager cap constitutive model was used to simulate the stress-strain behaviours of the soil. A series of laboratory tests were conducted to identify the elastoplastic properties of the composite soil used to bury the pipes. The FE models were calibrated using a physical lab model for testing the buried pipes under applied load. This allows the FE model to be confidently upgraded to a full-scale model. The pipe-soil interactions were found to be significantly influenced by the soil properties, the method of placing the pipes in the trench and the diameters of the buried pipes. The deformation of the surface soil was decreased by approximately 10% when using the new method of setting up the separate sewer.

Effect of a Degenerated C5-C6 Disc on the Biomechanics of Adjacent Levels: A Poroelastic Finite Element Investigation

2007 ◽  
Author(s):  
Mozammil Hussain ◽  
Raghu N. Natarajan ◽  
Gunnar B. J. Andersson ◽  
Howard S. An
Keyword(s):  
Finite Element ◽  
Cervical Spine ◽  
Morphological Changes ◽  
Axial Strain ◽  
Fe Model ◽  
Fe Method ◽  
Regional Effect ◽  
In Vitro Techniques

Degenerative changes in the cervical spine due to aging are very common causes of neck pain in general population. Although many investigators have quantified the gross morphological changes in the disc with progressive degeneration, the biomechanical changes due to degenerative pathologies of the disc and its effect on the adjacent levels are not well understood. Despite many in vivo and in vitro techniques used to study such complex phenomena, the finite element (FE) method is still a powerful tool to investigate the internal mechanics and complex clinical situations under various physiological loadings particularly when large numbers of parameters are involved. The objective of the present study was to develop and validate a poroelastic FE model of a healthy C3-T1 segment of the cervical spine under physiologic moment loads. The model included the regional effect of change in the fixed charged density of proteoglycan concentration and change in the permeability and porosity due to change in the axial strain of disc tissues. The model was further modified to include various degrees of disc degeneration at the C5-C6 level. Outcomes of this study provided a better understanding on the progression of degeneration along the cervical spine by investigating the biomechanical response of the adjacent segments with an intermediate degenerated C5-C6 level.

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