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Chronic otitis media enables the appearance of a benign middle ear tumor, known as a cholesteatoma, that may compromise hearing. To evaluate the influence of a cholesteatoma growth on the hearing function, a computational middle ear model based on the finite element method was used and three different size of cholesteatoma were modeled. The cholesteatoma solidification and the consequent degradation of the ossicles were also simulated as two condition that commonly occurs during cholesteatoma evolution. A sound pressure level of 80 dB SPL was applied in the tympanic membrane and a steady state analysis was performed for frequencies from 100 Hz to 10 kHz. The displacements of both the tympanic membrane and the stapes footplate were measured. The results were compared with a healthy case and it was shown that the cholesteatoma development leads to a decrease in the umbo and stapes displacements. The ossicles degradation simulation showed the higher difference comparing with the cholesteatoma in an initial stage, with lower displacements in the stapes footplate mainly for high frequencies. The observed displacement differences are directly connected to hearing loss, being possible to conclude that cholesteatoma evolution in the middle ear will lead to hearing problems, mainly in an advanced stage.

Meniere's disease is an inner ear disorder, associated with episodes of vertigo, fluctuant hearing loss, tinnitus, and aural fullness. Meniere's disease is associated with endolymphatic hydrops. Clinical evidences show that this disease is often incapacitating, negatively affecting the patients' everyday life. The pathogenesis of Meniere's disease is still not fully understood and remains unclear. Previous numerical studies available in the literature related with endolymphatic hydrops, are very scarce. The present work applies the finite element method to investigate the consequences of endolymphatic hydrops in the normal hearing, associated with the Meniere's disease. The obtained results for the steady state dynamics analysis are in accordance with clinical evidences. The results show that the basilar membrane is not affected in the same intensity along its length and that the lower frequencies are more affected by the endolymphatic hydrops. From a clinical point of view, this work shows the relationship between the increasing of the endolymphatic pressure and the development of hearing loss.

Hearing impairment is one of the most common health disorders, affecting individuals of all ages, reducing considerably their quality of life. At present, it is known that during an acoustic stimulation a travelling wave is developed inside the cochlea. Existing mathematical and numerical models available in the literature try to describe the shape of this travelling wave, the majority of them present a set of approaches based on some limitations either or both of the mechanical properties used and the geometrical description of the realistic representation. The present numerical study highlights the distinctions of using a spiral model of the cochlea, by comparing the obtained results with a straight, or simplified model. The influence of the implantation of transversely isotropic mechanical models was also studied, by comparing the basilar membrane with isotropic and transversely isotropic mechanical properties. Values of the root mean square error calculated for all models show a greater proximity of the cochlear mapping to the Greenwood function when the basilar membrane is assumed with transversely isotropic mechanical properties for both straight and spiral model. The root-mean square errors calculated were: 2.05, 1.70, 2.72, 2.08 mm, for the straight-isotropic, straight-transversely isotropic, spiral-isotropic and spiral-transversely isotropic model, respectively.

The cupula is a part of the inner ear semi-circular canals that plays an important role in the maintenance of the human balance. In order to understand the dynamic response of the cupula, first it is necessary to obtain its vibration frequencies. A two-dimensional and three-dimensional geometrical model of the cupula was built. Then, a free vibration analysis was performed using two distinct numerical techniques, the finite element method (FEM) and the natural neighbor radial point interpolation method (NNRPIM). Besides the fundamental analysis, other scenarios were studied, aiming to analyze the environment of the cupula (in healthy and pathologic scenarios). The results obtained with the geometrical models show that NNRPIM is capable to deliver results very close with the FEM. Additionally, the NNRPIM formulation possesses a high convergence and acceptable computational costs. This work presents for the first time a computational study on the free vibration analysis of the cupula and shows an alternative numerical technique to calculate with precision the natural frequency of the cupula. The outcomes of this work will allow the development of alternative therapies for cupulolithiasis, which causes severe dizziness.

A cochlear implant is an electronic device implanted into the cochlea to directly stimulate the auditory nerve. Such device is used in patients with severe-to-profound hearing loss. The cochlear implant surgery is safe, but involves some risks, such as infections, device malfunction or damage of the facial nerve and it can result on a poor hearing outcome, due to the destruction of any present residual hearing. Future improvements in cochlear implant surgery will necessarily involve the decrease of the intra-cochlear damage. Several implant related variables, such as materials, geometrical design, processor and surgical techniques can be optimized in order for the patients to partially recover their hearing capacities The straight electrode is a type of cochlear implant that many authors indicate as being the less traumatic. From the finite element analysis conducted in this work, the influence of the insertion speed, the friction coefficient between the cochlear wall and the electrode array, and several configurations of the cochlear implant tip were studied. The numerical simulations of the implantation showed the same pattern of the insertion force against insertion depth, thus indicating the different phases of the insertion. Results demonstrated that lower insertion speeds, friction coefficients and tip stiffness, led to a reduction on the contact pressures and insertion force. It is expected that these improved configurations will allow to preserve the residual hearing while reducing surgical complications.

The inner ear has two main parts, the cochlea, dedicated to hearing, and the vestibular system, dedicated to balance. Dizziness and vertigo are the main symptoms related to vestibular disorders, which commonly affects older people. In order to eliminate these symptoms a vestibular rehabilitation is performed; this consists in a range of movements of the head, known as maneuvers, performed by a clinical professional. This procedure does not always work as expected. The aim of this work is to contribute to a better understanding on how the vestibular system works. This knowledge will help in the development of new techniques that will facilitate a more efficient rehabilitation. In order to achieve that goal, a three-dimensional numerical model of the vestibular system, containing the fluids which promote the body balance, was constructed. The vestibular components will be discretized using the finite element method and the fluid flow will be analyzed using the Smoothed Particle Hydrodynamics. The results obtained with the numerical model of the semicircular canal built to study the rehabilitation process are presented and compared with other authors. The solution achieved is similar with literature.

O Antígeno 1 de Membrana Apical (AMA-1) tem sido sugerido como candidato a compor uma vacina contra estágios assexuados sanguíneos de Plasmodium. Recentemente nosso grupo identificou o domínio II (DII) de AMA-1 de Plasmodium vivax (PvAMA-1) como uma região altamente reconhecida por anticorpos IgG de indivíduos brasileiros infectados por P. vivax. No presente estudo avaliamos as propriedades imunogênicas da proteína recombinante DII, produzida a partir de Escherichia coli. Grupos de 6 camundongos fêmeas BALB/c foram imunizados quatro vezes com 10 µg dessa proteína na presença de diferentes formulações de adjuvantes [Adjuvante Completo/Incompleto de Freund (ACF/AIF), MPL-TDM, TiterMax, Hidróxido de Alumínio (Alum), Quil A, QS-21 e CpG-ODN 1826], individualmente, ou em combinação (Alum + QS-21 ou Alum + CpG-ODN 1826)). Nosso objetivo foi avaliar comparativamente a resposta de anticorpos (IgM, IgG e isotipos de IgG), induzida pelos diferentes esquemas de imunizações, visando futuros estudos pré-clínicos em primatas não humanos. Os títulos de anticorpos IgG contra (o ectodomínio) PvAMA-1 foram determinados por ELISA, duas semanas após cada imunização. A presença de IgM e dos isotipos de IgG também foi avaliada após o final do esquema de imunizações. Nossos resultados demonstraram que a proteína recombinante DII foi altamente imunogênica em camundongos BALB/c quando administrada na presença dos adjuvantes testados. Altos títulos de IgG1, IgG2a e IgG2b foram observados na maioria dos grupos (com exceção do adjuvante Alum), sugerindo uma resposta mista Th1/Th2. Finalmente, demonstramos que anticorpos monoclonais e policlonais anti-DII reconheceram a proteína nativa expressa na superfície de merozoítas de P. vivax, por imunofluorescência. Em conclusão, nossos resultados mostraram que a proteína recombinante o domínio II de PvAMA-1 (DII) foi imunogênico em camundongos BALB/c quando administrado na presença das diferentes formulações de adjuvantes testadas, sugerindo que esse antígeno possa ser utilizado como uma vacina de subunidade contra a malária vivax. The Apical Membrane Antigen 1 (AMA-1) has been considered a malaria vaccine candidate against asexual blood stages of Plasmodium. Recently, we identified the domain II (DII) of Plasmodium vivax AMA-1 (PvAMA-1) as a region highly recognized by IgG antibodies from Brazilian individuals infected by P. vivax. In the present study, we evaluated the immunogenic properties of a bacterial recombinant PvAMA-1 DII. Groups of 6 female BALB/c were immunized four times with 10 µg of recombinant protein in the presence of different adjuvant formulations [Complete/Incomplete Freunds Adjuvant (CFA/IFA), MPL-TDM, TiterMax, Aluminum hydroxide (Alum), Quil A, QS-21, CpG-ODN 1826] separately or in combination (Alum + QS-21 or Alum + CpG-ODN 1826). Our goal was to compare the antibody response (IgM, IgG and IgG subclass) induced by different protocols of immunization aiming at future pre-clinical studies in non-human primates. The IgG antibody titers against PvAMA-1 were determined by ELISA two weeks after each immunizing dose. The presence of IgM and IgG subclass were evaluated after the end of immunizations schedule. We found that the recombinant DII was highly immunogenic in BALB/c mice when administered in the presence of all adjuvant tested. High titers of IgG1, IgG2a and IgG2b were observed in all groups (except for Alum adjuvant), suggesting a mixed Th1/Th2 response. Finally, we demonstrated that monoclonal and polyclonal antibodies against DII recognized the native protein expressed on the P. vivax merozoite surface parasites by immunofluorescence. Together, our data demonstrated that the recombinant PvAMA-1(DII) was immunogenic in mice when administered in different adjuvant formulations, suggesting that this protein can be used as part of a sub-unit vaccine against malaria vivax.

The vestibular system is located in the posterior portion of the inner ear. It is a key component to our sense of balance and movement. Any changes in this system can cause effects or symptoms such as dizziness, blurred vision, imbalance, and nausea, which are vertiginous syndrome indicators. Vertigo is reported as one of the most common symptoms in the world. It is considered the third most frequent complaint in medicine, transmitting a sense of inadequacy and insecurity. The aim of this work is to contribute to a better understanding of how the vestibular system works. This knowledge will help in the development of new techniques that will facilitate a more effective rehabilitation. Vestibular rehabilitation consists of a set of exercises, known as maneuvers, which can reduce and even eliminate symptoms of dizziness and imbalance associated with a vestibular disorder. In this work, a three-dimensional computational model of the vestibular system, containing the fluids promoting the body balance, will be presented. The smoothed-particle hydrodynamics (SPH) method will be used to simulate the fluid behavior. The results provide a better comprehension of the biomechanics of the vestibular system, which contribute to recover from any system disorders.

The ear is one of the most complex organs in the human body. Sound is a sequence of pressure waves, which propagates through a compressible media such as air. The pinna concentrates the sound waves into the external auditory meatus. In this canal, the sound is conducted to the tympanic membrane. The tympanic membrane transforms the pressure variations into mechanical displacements, which are then transmitted to the ossicles. The vibration of the stapes footplate creates pressure waves in the fluid inside the cochlea; these pressure waves stimulate the hair cells, generating electrical signals which are sent to the brain through the cochlear nerve, where they are decoded. In this work, a three-dimensional finite element model of the human ear is developed. The model incorporates the tympanic membrane, ossicular bones, part of temporal bone (external auditory meatus and tympanic cavity), middle ear ligaments and tendons, cochlear fluid, skin, ear cartilage, jaw and the air in external auditory meatus and tympanic cavity. Using the finite element method, the magnitude and the phase angle of the umbo and stapes footplate displacement are calculated. Two slightly different models are used: one model takes into consideration the presence of air in the external auditory meatus while the other does not. The middle ear sound transfer function is determined for a stimulus of 60 dB SPL, applied to the outer surface of the air in the external auditory meatus. The obtained results are compared with previously published data in the literature. This study highlights the importance of external auditory meatus in the sound transmission. The pressure gain is calculated for the external auditory meatus.

Vertiginous symptoms are one of the most common symptoms in the world, therefore investing in new ways and therapies to avoid the sense of insecurity during the vertigo episodes is of great interest. The classical maneuvers used during vestibular rehabilitation consist in moving the head in specific ways, but it is not fully understood why those steps solve the problem. To better understand this mechanism, a three-dimensional computational model of the semicircular ducts of the inner ear was built using the finite element method, with the simulation of the fluid flow being obtained using particle methods. To simulate the exact movements performed during rehabilitation, data from an accelerometer were used as input for the boundary conditions in the model. It is shown that the developed model responds to the input data as expected, and the results successfully show the fluid flow of the endolymph behaving coherently as a function of accelerometer data. Numerical results at specific time steps are compared with the corresponding head movement, and both particle velocity and position follow the pattern that would be expected, confirming that the model is working as expected. The vestibular model built is an important starting point to simulate the classical maneuvers of the vestibular rehabilitation allowing to understand what happens in the endolymph during the rehabilitation process, which ultimately may be used to improve the maneuvers and the quality of life of patients suffering from vertigo.

This work presents a biomechanical study of myringosclerosis (MS), an abnormal condition of the ear that produces calcification of the lamina propria of the eardrum. The study researched the transfer of sound to the stapes depending on the localization, dimension and calcification degree of the MS plaques. Results were obtained using a validated finite element model of the ear. The mechanical properties of the lamina propria were modified, in order to model MS plaques, using the rule of mixtures for particle composites considering that the plaques are made of hydroxyapatite particles in a matrix of connective tissue. Results show that the localization and dimension of the plaques are a factor of higher importance than calcification for loss of hearing through MS. The mobility of the stapes decreased with the presence of larger plaques and also when the tympanic annulus and the area of the handle of the malleus were involved.

The vestibular system is the part of the inner ear responsible for balance. Vertigo and dizziness are generally caused by vestibular disorders and are very common symptoms in people over 60 years old. One of the most efficient treatments at the moment is vestibular rehabilitation, permitting to improve the symptoms. However, this rehabilitation therapy is a highly empirical process, which needs to be enhanced and better understood.This work studies the vestibular system using an alternative computational approach. Thus, part of the vestibular system is simulated with a three dimensional numerical model. Then, for the first time using a combination of two discretization techniques (the finite element method and the smoothed particle hydrodynamics method), it is possible to simulate the transient behavior of the fluid inside one of the canals of the vestibular system.The obtained numerical results are presented and compared with the available literature. The fluid/solid interaction in the model occurs as expected with the methods applied. The results obtained with the semicircular canal model, with the same boundary conditions, are similar to the solutions obtained by other authors.The numerical technique presented here represents a step forward in the biomechanical study of the vestibular system, which in the future will allow the existing rehabilitation techniques to be improved.

Otitis media is a group of inflammatory diseases of the middle ear. Acute otitis media and otitis media with effusion (OME) are its two main types of manifestation. Otitis media is common in children and can result in structural alterations in the middle ear which will lead to hearing losses. This work studies the effects of an OME on the sound transmission from the external auditory meatus to the inner ear. The finite element method was applied on the present biomechanical study. The numerical model used in this work was built based on the geometrical information obtained from The visible ear project. The present work explains the mechanisms by which the presence of fluid in the middle ear affects hearing by calculating the magnitude, phase and reduction of the normalized umbo velocity and also the magnitude and phase of the normalized stapes velocity. A sound pressure level of 90 dB SPL was applied at the tympanic membrane. The harmonic analysis was performed with the auditory frequency varying from 100 Hz to 10 kHz. A decrease in the response of the normalized umbo and stapes velocity as the tympanic cavity was filled with fluid was obtained. The decrease was more accentuated at the umbo.

There are three basic types of hearing loss: conductive, sensorineural and mixed. Otosclerosis is a pathology which can originate any of these types of hearing loss. Otosclerosis is a bone dysplasia, present only in the temporal bone, and consists of single or multiple absorption areas followed by healing with bone neoformation. The clinical result of this pathology is a conductive deafness when a stapes footplate fixation occurs at the oval window or a sensorineural deafness when it affects the otic capsule involving the cochlear endosteum. Otosclerosis is categorised into two types, fenestral (stapedial type) and retrofenestral (cochlear type). Cochlear otosclerosis represents a continuation of the fenestral otosclerotic process and rarely occurs without fenestral involvement. The numerical model used in this work was build based on the geometrical information obtained from “The visible ear” project. A cryosectioning procedure was applied to the temporal bone of an 85 years old woman, without hearing pathologies, to obtain anatomical data. Afterwards, the different tissues were hand-segmented and a 3D model was constructed. The aim of this study is to contribute to the understanding of the alterations introduced by the fenestral otosclerosis in the human ear and its consequences on the earing capability, using a numerical analysis. The umbo and stapes displacements with the presence of fenestral otosclerosis were carried out for a stimulation of 80 dB SPL applied on the tympanic membrane. The stimulus was applied at frequencies ranging between 100 and 10 kHz. The main conclusion of this work is that the fenestral otosclerosis affects the motion of the stapes footplate, without changing significantly the umbo response.

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The three semicircular canals, arranged in three orthogonal planes, are the main components of the inner ear with the balance function. They are sensitive to angular acceleration [1,2]. Each canal is composed of a circular path of fluid continuity, interrupted at the cupula, where the sensory epithelium is placed — known as hair cells, which is the focus of this work. The hair cells exhibit constant discharge of neurotransmitters that are modified by the direction of cupula deflection. One of the causes of vestibular disorders is the abnormal concentration of otoconia particles in the vicinity of the cupula. Thus, the accurate determination of the natural frequency (first vibration mode) of the cupula will allow to stimulate externally the cupula. Theoretically, the resonance phenomena will disperse the otoconia particles, reducing the vertigo symptoms. In order to understand the dynamic response of the cupula, first it is necessary to obtain its free vibration modes. Thus, a 2D and 3D geometrical model of the cupula was constructed. Then, a free vibration analysis was performed using two distinct numerical techniques, such as the finite element method (FEM) and a radial point interpolation meshless method (RPIM). Meshless methods are advanced discretization techniques that allow to discretize the problem domain using only a cloud of points, allowing them to discretize geometrical models directly from medical images. The results obtained with the 2D and 3D geometrical model show that RPIM is capable to deliver results very similar with the FEM. However, the RPIM solution is smoother. On the other hand, the FEM computational cost is lower than the RPIM.

Hearing is one of the five senses in humans and one of the most important for their social life. The human ear is a complex organ which allows to understand and interpret sound waves for a band of frequencies between 16 Hz and 20 kHz and intensities ranging from 0 to 130 dB. The numerical model used in this work was built based on the geometrical information obtained from The visible ear project. A cryosectioning procedure was applied to the temporal bone of an 85 years old woman, without hearing pathologies, to obtain the anatomical data. Afterwards, the different tissues were hand-segmented and a 3D model was constructed. The finite element method was employed to obtain the umbo and stapes footplate displacements. A study of the external auditory meatus was carried out in order to study its influence on the human hearing. The model without the external auditory meatus was validated by comparing the displacements obtained for the umbo and stapes footplate, with other data in the literature. Subsequently, the external auditory meatus was introduced in the numerical model. The air was modelled with acoustic elements available in the Abaqus Standard software. In total, the model was discretized with 255 343 nodes and 1 345 379 elements. The results obtained showed the important role that the external auditory meatus has in amplifying the sound at higher frequencies. In the frequency band between 100 Hz and 10 kHz, two resonant frequencies were found. There was a significant gain in sound pressure near the tympanic membrane for the frequencies of 3 and 8 kHz. A phase shift of 180° near these frequencies, accompanied by a rapid increase in the displacement amplitude showed the presence of such resonances. The study can now proceed into the middle and inner ear in order to study the different types of pathologies and prostheses. The acoustic transmission in the cochlea remains understudied in this area.

SUMMARY Hearing is a sequence of processes in which the ear translates sound waves into electrical signals, which are then sent to the brain where they are interpreted as sound. The ossicular chain of the middle ear is formed by three ossicles (malleus, incus, and stapes), of which the last and smallest, the stapes, vibrates, thus communicating with the inner ear through the stapes footplate. When abnormal bone formation immobilizes the stapes (otosclerosis), the passage of sound does not correctly occur and hearing can be compromised. In most cases, surgery is an option for its treatment. The stapes is totally or partially replaced by a prosthesis (stapedectomy or stapedotomy, respectively) allowing the passage of sound to the inner ear. This work presents a study on the behavior of different stapes prostheses, considering their biomechanical characteristics. The stapes was replaced by different prostheses, made of dissimilar materials: stainless steel, teflon, and titanium. The umbo and stapes footplate displacements for the models with these prostheses were obtained and compared with the displacements obtained with the model representative of the normal ear. In the models with prostheses, the displacements are found in the hole where the prosthesis is attached. Copyright © 2014 John Wiley & Sons, Ltd.

The human ear is a complex biomechanical system and is divided into three parts: outer, middle and inner ear. The middle ear is formed by ossicles (malleus, incus and stapes), ligaments, muscles and tendons, which transfers sound vibrations from the eardrum to the inner ear, linking with mastoid and Eustachian tube. In this work, a finite element modelling of the tympano-ossicular system of the middle ear was developed. A dynamic study based on a structural response to harmonic vibrations, for a sound pressure level (SPL) of 110, 120 and 130 dB SPL applied in the eardrum, is presented. The connection between the ossicles is made using a contact formulation. The model includes the different ligaments considering its hyperelastic behaviour. The activation of the muscles is based on the constitutive model proposed by previous work. The harmonic responses of displacement and pressure obtained on the stapes footplate, for a frequency range between 100 Hz and 10 kHz, are obtained simulating the muscle activation. The results are compared considering the passive and active states. The results are discussed and they are in accordance with audiological data published with reference to the effects of the middle ear muscles contraction.

Otosclerosis is a metabolic bone disease of the otic capsule that can cause the stapes fixation, resulting in conductive hearing loss or, in a profound sensorineural deafness threshold. Surgery is one of the possible treatments for the otosclerosis. To repair small focus of otosclerosis in the anterior crus of the stapes, in 1960, Hough suggested the implementation of a technique in which part of the anterior crus is fractured and the stapes turned. As a result, the posterior crus of the stapes is the only connection with the inner ear. In this work, the outcome of Hough's surgical technique was simulated.Based on computerized images, a finite element model of middle ear ossicles and tympanic membrane was created, as well as a model where the stapes has changed. The discretization of the tridimensional solid model was made using the ABAQUS software. The mechanical properties used were taken from the literature and adequate boundary conditions were applied.The results obtained with the Hough technique simulation were compared with a representative model of the normal ear, taking into account the displacements obtained on the central part of the stapes footplate and the maximum principal stress in the stapes crus.The results obtained are closer to the normal ear model, therefore Hough technique stands out as a good option to correct small focus of otosclerosis.

O objetivo deste trabalho foi estudar a influência de diferentes fluidos dentro e fora da cavidade timpânica no comportamento biomecânico do ouvido médio. O modelo computacional 3 D da cadeia tímpano‐ossicular foi construído através de imagens de tomografia axial computorizada (TAC). Após a construção do modelo da cadeia tímpano‐ossicular, para a parte interna da membrana timpânica foi criada a caixa timpânica, que inclui toda a cadeia ossicular, e para a parte externa da membrana foi criada uma passagem, simulando o canal auditivo externo. A discretização do modelo foi feita utilizando o método dos elementos finitos, com base no software ABAQUS. As propriedades mecânicas foram extraídas de trabalhos anteriores. Foram obtidos os deslocamentos do umbo e de um ponto central da platina do estribo, para um nível de pressão sonora de 105 dB aplicada na membrana timpânica, comparando a cadeia tímpano‐ossicular e os diferentes níveis de pressão externa e interna do ouvido médio (fluido líquido e fluido gasoso). Os resultados demonstram que o comportamento biomecânico do ouvido médio é diferente para os diferentes níveis de pressões testadas neste modelo. Quando utilizada uma pressão de fluido líquido, os deslocamentos são de amplitude inferior quando comparados com os resultados obtidos com pressão de ar., The objective of this work is to study the influence of different fluids of the tympanic cavity into the biomechanical behavior of the middle ear. The 3 D computer model of the tympanic ossicular chain was built using images from computed tomography (CT). After construction of the tympanic ossicular chain model, it was adapted the simulation by placing the passage to the external auditory canal and to the tympanic cavity. The discretization of the model was made using the finite element method based on ABAQUS software. The mechanical properties were extracted from previous works. The umbo and the stapes footplate displacements, for a sound pressure level of 105 dB applied in tympanic membrane were obtained, comparing the tympanic ossicular chain and the different levels of external and internal pressure in the middle ear (liquid and air). The results demonstrate that the biomechanical behavior of the middle ear is different for different levels of pressure tested in this model. When using liquid, displacements are of lower amplitude when compared with the results obtained with air

The eardrum separates the external ear from the middle ear and it is responsible to convert the acoustical energy into mechanical energy. It is divided by pars tensa and pars flaccida. The aim of this work is to analyze the susceptibility of the four quadrants of the pars tensa under negative pressure, to different lamina propria fibers distribution. The development of associated ear pathology, in particular the formation of retraction pockets, is also evaluated. To analyze these effects, a computational biomechanical model of the tympano-ossicular chain was constructed using computerized tomography images and based on the finite element method. Three fibers distributions in the eardrum middle layer were compared: case 1 (eardrum with a circular band of fibers surrounding all quadrants equally), case 2 (eardrum with a circular band of fibers that decreases in thickness in posterior quadrants), case 3 (eardrum without circular fibers in the posterior/superior quadrant). A static analysis was performed by applying approximately 3000Pa in the eardrum. The pars tensa of the eardrum was divided in four quadrants and the displacement of a central point of each quadrant analyzed. The largest displacements of the eardrum were obtained for the eardrum without circular fibers in the posterior/superior quadrant.

In this study, the biomechanical behaviour of the human hearing was studied. An accurate finite element model can be used to evaluate the influence of certain hearing diseases and aid in their treatment, as well as help to comprehend the phenomenon of sound transmission. This research was based on the project "The Visible Ear" developed by a group of Danish students in order to obtain a set of high quality images of the temporal bone, using a "cryosectioning" procedure [1]. This project allowed the development of the computational models used. CAD software was used to treat each of the parts that compose the human ear. The first tested model (simple model) was composed of the tympanic membrane, ossicles, cochlea, two muscles, six ligaments, two joints, and the temporal bone. The full model was based on the simple model adding air to the external auditory canal and middle ear, the skin, the jaw and the ear cartilage. Comparing the results obtained by both models, it was possible to understand the importance of the ear canal in the transmission of the sound to the eardrum. The models were simulated numerically with the Abaqus software. The natural frequencies, displacements of the umbo and stapes footplate were obtained for both models, for different sound pressure levels. The frequency band used in this study was between 100 Hz and 10 kHz.

The aim of this work is to contribute to a better understanding on how the vestibular system works. This knowledge will help in the development of new techniques that will facilitate a more efficient rehabilitation. Vestibular rehabilitation consists in a set of exercises, known as maneuvers, which can reduce and even eliminate the symptoms of dizziness and imbalance associated with a vestibular disorder. In this work, a three-dimensional model of the vestibular system, containing the fluids which promote the body balance, will be used. One of the aims is to simulate the fluid behaviour and the study of its interaction with the soft tissues of the vestibular structure. This model will allow the simulation of the maneuvers of the vestibular rehabilitation in order to improve its results and the quality of life of patients suffering from vertigo.

The ear is a complex organ that can be affected by various pathologies that are still fairly misunderstood. This work tests the possibilities of studying the ear and its pathologies using a virtual environment and thus bypassing expensive and time-consuming clinical trial. A previous validated finite element model of the middle ear was employed to study two pathological states of the middle ear. It was shown that the model obtained results very close to the clinical evaluation thus proving of being a proper tool for further investigations of middle ear pathologies.

Introduction: Tinnitus is an auditory sensation whose source comes from external stimulus to the body. All studies that can help people with this disorder are very imperative. Objective: This study investigates the cochlear function in patients with tinnitus, using Distortion Products Otoacoustic Emissions (DPOAE). Material and Methods: Ears where the subjects referred to feel the tinnitus were considered for the study group while other ears without this sensation of tinnitus acted as a control group. Fifty subjects suffering from unilateral or bilateral tinnitus with normal hearing sensitivity or mild hearing loss were recruited. Results and conclusions: Where comparing the control and study group, the highest percentage of cases of DPOAE detected was in the control group, although these differences were not statistically significant. When the analyzed frequency is the same as the tinnitus frequency, the prevalence of detected DPOAE is in tinnitus ears (50.0 %). In ears where tinnitus was not perceived (73.5 %) a p value of 0.024 (< 0.05) was found, which means that the undetected DPOAE could be influenced by tinnitus. Based on the results, tinnitus might not be caused by changes in the outer hair cells but seems to be affected by that.

The main goal of the present study is to analyze and characterize the behavior of the middle ear, when a total ossicular replacement prosthesis (TORP) is used in the ossicular chain, in order to troubleshoot conductive hearing loss. Using a finite element model (FEM), a dynamic study of the middle ear was made. The displacement values were obtained at the umbo and stapes footplate, for a sound pressure level of 80 dB sound pressure level (SPL) applied at the tympanic membrane, when a cartilage in membrane-prosthesis interface of different diameters and thicknesses was used. The results were compared with the healthy middle ear model. The usage of this model aims to achieve a set of techniques that promotes the best possible performance of prosthesis in the middle ear. The present study allows to conclude that the rehabilitation of the middle ear with TORP can lead to the best results when used with 4 mm diameter cartilages, with a thin thickness of 0.3 mm.

This work investigates the effect of eardrum perforations and myringosclerosis in the mechanical behavior of the tympano-ossicular chain. A 3D model for the tympano-ossicular chain was created and different numerical simulations were made, using the finite element method. For the eardrum perforations, three different calibers of perforated eardrums were simulated. For the micro perforation (0.6 mm of diameter) no differences were observed between the perforated and normal eardrum. For the numerical simulation of the eardrum with the largest perforation caliber, small displacements were obtained in the stapes footplate, when compared with the model representative of normal ossicular-chain, at low frequencies, which is related with major hearing loss in this frequency range. For the numerical simulations of myringosclerosis, the larger differences in the displacement field between the normal and modified model were obtained in the umbo. When observing the results in the stapes footplate, there were no significant differences between the two models, which is in accordance to the clinical data. When simulating an eardrum perforation along with myringosclerosis, there is a decrease in the displacements, both from the umbo and the central part of the stapes footplate, often associated with a pronounced hearing loss. It could be concluded that the reduced displacement of the stapes footplate may be related to a greater hearing loss.

In recent years, the segmentation, i.e. the identification, of ear structures in video-otoscopy, computerised tomography (CT) and magnetic resonance (MR) image data, has gained significant importance in the medical imaging area, particularly those in CT and MR imaging. Segmentation is the fundamental step of any automated technique for supporting the medical diagnosis and, in particular, in biomechanics studies, for building realistic geometric models of ear structures. In this paper, a review of the algorithms used in ear segmentation is presented. The review includes an introduction to the usually biomechanical modelling approaches and also to the common imaging modalities. Afterwards, several segmentation algorithms for ear image data are described, and their specificities and difficulties as well as their advantages and disadvantages are identified and analysed using experimental examples. Finally, the conclusions are presented as well as a discussion about possible trends for future research concerning the ear segmentation.

Hearing is a sequence of processes in which the ear translates sound waves into electrical signals, which are then sent to the brain where they are interpreted as sound. The ossicular chain of the middle ear is formed by three ossicles (malleus, incus, and stapes), of which the last and smallest, the stapes, vibrates, thus communicating with the inner ear through the stapes footplate. When abnormal bone formation immobilizes the stapes (otosclerosis), the passage of sound does not correctly occur and hearing can be compromised. In most cases, surgery is an option for its treatment. The stapes is totally or partially replaced by a prosthesis (stapedectomy or stapedotomy, respectively) allowing the passage of sound to the inner ear. This work presents a study on the behavior of different stapes prostheses, considering their biomechanical characteristics. The stapes was replaced by different prostheses, made of dissimilar materials: stainless steel, teflon, and titanium. The umbo and stapes footplate displacements for the models with these prostheses were obtained and compared with the displacements obtained with the model representative of the normal ear. In the models with prostheses, the displacements are found in the hole where the prosthesis is attached.

Molecular dynamics is a well-known technique very much used in the study of biomolecular systems. The trajectory files produced by molecular dynamics simulations are extensive, and the classical lossless algorithms give poor efficiencies in their compression. In this work, a new specific algorithm, named byte structure variable length coding (BS-VLC), is introduced. Trajectory files, obtained by molecular dynamics applied to trypsin and a trypsin:pancreatic trypsin inhibitor complex, were compressed using four classical lossless algorithms (Huffman, adaptive Huffman, LZW, and LZ77) as well as the BS-VLC algorithm. The results obtained show that BS-VLC nearly triplicates the compression efficiency of the best classical lossless algorithm, preserving a near lossless behavior. Compression efficiencies close to 50% can be obtained with a high degree of precision, and the maximum efficiency possible (75%), within this algorithm, can be performed with good precision.

Hereby it is presents a novel methodology to segment the internal structures of the human ear based on image registration. The first step of the methodology concerns the registration of the volumetric image to be segmented with a reference volumetric image previously defined and manually segmented. Then, the geometric transformation found in the registration step is applied to the image to be segmented and consequently, the segmentation of this image is achieved. The methodology was applied on a set of images obtained by X-ray computed tomography revealing very promising results.

The stapes, the smallest bone in the human body, is the third component in the tympano-ossicular chain of the middle ear. Otosclerosis is a disease that can cause stapes fixation, resulting in different kind of hearing losses. It is a disorder that involves the growth of abnormal bone around stapes footplate. The tonal and vocal audiometry, tympanometry, and acoustic reflexes, are the most used diagnostic tests. The treatment can be done by amplification with hearing aids or more effective, by surgery. To correct small focus of otosclerosis, Hough, in 1960, suggested the implementation of a technique (Figure 1) in which part of the anterior crura is breached and the posterior one is rotated, getting only the connection between the stapes footplate and the inner ear made through the posterior crura [Glasscock et al., 1995].

O sistema auditivo humano está inserido no grupo dos sentidos especiais, pois possui receptores altamente localizados que proporcionam informação específica sobre o ambiente que o rodeia. Este sistema compreende os órgãos responsáveis pela função auditiva e pelo equilíbrio. O ouvido humano divide-se em ouvido externo, ouvido médio e ouvido interno. Este último é constituído por três estruturas principais: os canais semicirculares, o vestíbulo, que contém o utrículo e o sáculo, e a cóclea [1]. No estudo clínico do ouvido interno são utilizadas frequentemente imagens médicas obtidas através de diferentes técnicas; nomeadamente, Tomografia Computorizada (CT-standard, Micro-CT, Spiral-CT) [2-4], Ressonância Magnética (MR-standard, Micro-MR) [5-7] e ainda Microscopia de Secções Histológicas [8]. Tais imagens são também adquiridas com o propósito de criar modelos geométricos com características morfológicas e dimensões semelhantes às do ouvido interno de forma a possibilitar o seu estudo de forma realista. Para tal, utilizam-se técnicas de processamento e análise de imagem, em particular de segmentação de imagem [9]. Contudo, a representação do ouvido interno em tais imagens apresenta problemas de complexidade elevada e, por isso, a segmentação das suas estruturas, isto é, a sua identificação, é efectuada frequentemente de forma manual. Contudo, estão a ser desenvolvidas metodologias computacionais que permitem a segmentação de tais estruturas de forma semi ou mesmo totalmente automática. Neste artigo, tais metodologias de segmentação de imagem são introduzidas e analisadas tendo em consideração os resultados obtidos em imagens do ouvido interno, bem como identificadas algumas das vantagens e desvantagens de cada uma.