Human Middle Ear Research Articles

Risks of Ear Complaints of Passengers and Drivers While Trains Are Passing Through Tunnels at High Speed: A Numerical Simulation and Experimental Study.

Ear complaints induced by interior pressure transients are common experiences for passengers and crew members when high-speed trains are passing through tunnels. However, approaches to assessing the risks of the pressure-related aural discomfort have not been reported until recently. The objective of this study was to evaluate the hazards of interior pressure transients of high-speed train on human ears combining the effects of operation speed and seal index. Moving model tests were conducted to obtain the pressure transients when the model train runs in the tunnel. The recorded data were transformed into the interior pressures by empirical formula. Furthermore, the aural sensations were divided into four levels hierarchically and the range for each level was derived by logistic regression analysis method and represented by three biomechanical metrics. Furthermore, a human middle ear finite element (FE) model was used to simulate its dynamics under the interior pressures. The results indicate that lifting operation speed from 250 km/h to 350 km/h in tunnel will prolong the duration of ear complaints by more than two times whereas improving the seal index from 4 s to 12 s will reduce the incidences of the onset of tinnitus and hearing loss by more than ten times. In addition, the duration of aural comfort shortens from the head car to the tail car against the running direction. It is desirable that enhancing the seal index improve the aural sensations of the passengers and crew members considering the lifting operation speed of high-speed train.

Human ear finite element model study of the effects of ear canal and middle ear cavity on air conduction and bone conduction

Objective:To study the influence of the ear canal and middle ear cavity on air conduction and bone conduction. Method:A finite element model of the human middle ear was established. By establishing the external ear canal and the middle ear cavity, we evaluated the effects of the external canal and the middle ear cavity on air conduction and bone conduction. Result:In air conduction, the external canal improved the stapes response at the frequency range of 0.5 kHz to 6 kHz, and the maximum increase was 11 dB at 3 kHz. The middle ear cavity mainly reduced the response of stapes at mid-low frequency, with the drops of 2-4 dB under 2 kHz; in bone conduction, ear canal slightly reduced the low-frequency response, but increased the response of the stapes at the mid-high frequency, with a maximum increase of 1.9 dB at 1.5 kHz. The middle ear cavity mainly increased the stapes response at mid-frequency near 1.5 kHz, with a maximum increase of 2.5 dB. Conclusion:Our results show that, in air conduction, the ear canal significantly increases the middle-frequency response, while the middle ear cavity decreases the low-mid frequency response. Whereas, the ear canal and the middle ear cavity have slightly effect on bone conduction.

Determination of Resonant Frequencies of an Acoustical System of the Human by Means of Objective Methods of a Research of Hearing

Different pathological processes lead to changes of human auditory system characteristics. Nowadays, hearing diagnosis is not surprising and does not cause unnecessary questions, because most people understand the importance of health care and know about problems that can arise if they are not warned in advance. In the world there are many methods and programs for objective diagnosis of human hearing. Today, among hearing diagnosing objective methods, multifrequency acoustic impedancemetry and otoacoustic emission are most widely used in clinical practice. Comparison of the obtained characteristics in normal and pathological conditions allows us to judge the degree of changes in the auditory organ and diagnose some of its diseases. However, a large discrepancy between intersubject data may overlap deviations from norms. This is the main problem in diagnosis of hearing system. Determination the resonant frequency of human auditory system structural elements in a comprehensive study, using objective methods gives us a possibility to detect changes in ear conductive system more accurately. Significant changes in the resonance frequency of human middle ear make it possible to detect an existing pathology at a functional level. Resonant frequency shift (to one or the other side) may indicate the presence of otosclerosis, auditory ossicles chain break, etc. In this work, the parameters of the human middle ear were obtained theoretically, based on a two-circuit model of the human middle ear, and confirmed experimentally, using tympanometry and otoacoustic emission, which eliminate the main problem of hearing diagnostics and offer new diagnostic parameters for sound-conducting ear system diseases diagnosing, namely, value of resonant frequencies. Determining the resonant frequency of human auditory system structures in a comprehensive study using objective methods, allows us to identify changes in ear sound-conducting system. To study human auditory system resonant frequency, an electromechanical model of human middle ear was selected and its main parameters were determined: eardrum and tympanic cavity flexibility, acoustic impedance of air in the tympanic cavity and auditory tube, resonant frequency of first and second circuits of middle ear vibrating system, auditory ossicles weight. Purpose of the study - to search and identify effective ways to improve objective acoustic diagnostic methods and substantiate the choice of tympanometry and otoacoustic emission as the main methods for studying the state of the human auditory system, which allow a detailed assessment of pathological processes. Ref. 10, fig. 2, tabl. 1.`

The Goat Model for Exclusive Two Handed Endoscopic Middle Ear Surgery Training: A Novel Technique.

With the popularity of exclusive transcanal endoscopic ear surgery, the need for a suitable and affordable surgical training model has grown. To develop an ex vivo animal model for exclusive endoscopic ear surgery. In an experimental study, we studied goat middle ear anatomy in 8 specimens to assess the similarity with the human middle ear as a model for two handed endoscopic ear surgery with endoscope holders. After confirming its suitability, we have developed a surgical training program for grommet insertion, canaloplasty, myringoplasty, butterfly tympanoplasty, ossiculoplasty, atticotomy. The goat model is suitable for two handed endoscopic ear surgery using endoscope holder. We describe a novel, exclusively two handed endoscopic approach in an ex vivo animal model for middle ear surgery. The proposed surgical program will guide the trainee endoscopic ear surgeon for a step by step through the main otologic procedures to enhance his or her surgical skills.

Study of optimal evaluation procedure of ossicular mobility: Numerical analysis using FE-model of human middle ear

Study of optimal evaluation procedure of ossicular mobility: Numerical analysis using FE-model of human middle ear

A study of transfer function of human middle ear by bone conduction

Vibration of tympanic membrane induced by sound is transmitted to a cochlea via middle-ear ossicular chain and stimulates an auditory nerve. Hearing sensation produced by sound is described as air conduction. Vibration of a skull induced by vocal sound is also transmitted to a cochlea. Hearing sensation produced by vibration of a skull is described as bone conduction. Therefore, human vocal sound is perceived by means of two pathways, air and bone conduction. In the present study, the roll of the ossicular chain of bone conduction is analyzed numerically by using a technique of multibody dynamics. The numerical model of the ossicular chain is created precisely by using pictures of computerized axial tomography scan. The vibrational responses of the ossicular chain and the force transmitted to a cochlea induced by the stimuli of air and bone conduction ware calculated. The magnitude of the force induced by the bone conduction was about one third of that induced by the air conduction.

Multiphoton imaging for morphometry of the sandwich-beam structure of the human stapedial annular ligament

BackgroundThe annular ligament of the human stapes constitutes a compliant connection between the stapes footplate and the peripheral cochlear wall at the oval window. The cross section of the human annular ligament is characterized by a three-layered structure, which resembles a sandwich-shaped composite structure. As accurate and precise descriptions of the middle-ear behavior are constrained by lack of information on the complex geometry of the annular ligament, this study aims to obtain comprehensive geometrical data of the annular ligament via multiphoton imaging. MethodsThe region of interest containing the stapes and annular ligament was harvested from a fresh-frozen human temporal bone of a 46-years old female. Multiphoton imaging of the unstained sample was performed by detecting the second-harmonic generation of collagen and the autofluorescence of elastin, which are constituents of the annular ligament. The multiphoton scans were conducted on the middle-ear side and cochlear side of the annular ligament to obtain accurate images of the face layers on both sides. The face layers of the annular ligament were manually segmented on both multiphoton scans, and then registered to high-resolution μCT images. ResultsMultiphoton scans of the annular ligament revealed 1) relatively large thickness of the core layer compared to the face layers, 2) asymmetric geometry of the face layers between the middle-ear side and cochlear side, and variation of their thickness and width along the footplate boundary, 3) divergent relative alignment of the two face layers, and 4) different fiber composition of the face layers along the boundary with a collagen-reinforcement near the anterior pole on the middle-ear side. Conclusion and outlookMultiphoton microscopy is a feasible approach to obtain the detailed three-dimensional features of the human stapedial annular ligament along its full boundary. The detailed description of the sandwich-shaped structures of the annular ligament is expected to contribute to modeling of the human middle ear for precise simulation of middle-ear behavior. Further, established methodology in this study may be applicable to imaging of other middle-ear structures.

Characterization of harmonic response of human middle ear using finite element approach

Human middle ear (ME) is an important organ of the auditory system. Sound energy stimulates the cochlear fluids present in the inner ear. Ossicular chain, a part of human middle ear consists of Tympanic membrane (TM), ossicles, ligaments and muscles. Hearing loss is reported when the ossicles in the chain gets degraded. Surgical intervention is one of the approaches to overcome the situation. The possibility of replacement of damaged ossicles with normal biocompatible biomaterials is explored in the current study. To study the sound transfer function, a FE model is developed using μCT (Computed Tomography) scan data imported in MIMICS Research 19.0 (Materialise Interactive Medical Image Control System) modeling software. The harmonic response at the stapes footplate and umbo is examined with the assumption that sound pressure is incident from lateral side of eardrum. Pathological conditions are analysed to determine the gain or loss in hearing capacity for Cholesteatoma, Partial mallear fixation and variations of material properties in Tympanic membrane (TM). The human audible sound pressure levels (SPLs) of 60, 80, 100 and 120 dB are applied on eardrum within frequency range of 100 Hz–10,000 Hz. The results are compared with healthy ear to investigate gain or loss in hearing capacity for these pathologies.

In Vivo Measurement of Middle Ear Pressure Changes during Balloon Eustachian Tuboplasty.

Background Balloon Eustachian tuboplasty (BET) is known as a treatment for chronic obstructive Eustachian tube dysfunction (OETD). The precise mechanism of action is not fully understood. Observations in sheep cadavers and human cadavers have shown specific middle ear pressure changes related to BET. Methods In this prospective study using a microfibre optical pressure sensor, pressure changes during BET were for the first time monitored transtympanically in five normal human middle ears in vivo. Results Middle ear pressure changes during 21 BETs consisted of five stages (insertion, inflation, deflation, withdrawal, and recovery). The highest pressure change occurred in most of the cases during the withdrawal of the balloon catheter. Withdrawal pressure yielded a mean middle ear pressure of 4.76 mmHg (61.89 daPa) with a maximum of 13.88 mmHg (179.55 daPa). Pressure amplitudes capable of causing barotrauma to ear structures were not detected. Internal carotid artery dehiscences were detected as causative of sinusidual pressure changes. Conclusion The middle ear pressure changes detected in vivo during BET can be attributed to the balloon inflation. Further human studies with patients affected by OETD are necessary to gain more insight into the mechanism of action of BET to clarify a possible pressure related second mechanism of action of BET.

Corrigendum to "Effect of Lead on Human Middle Ear Epithelial Cells".

[This corrects the article DOI: 10.1155/2018/5058729.].

Taraxerol exerts potent anticancer effects via induction of apoptosis and inhibition of Nf-kB signalling pathway in human middle ear epithelial cholesteatoma cells

Purpose : To investigate the effect of taraxerol on the proliferation of middle ear epithelial cholesteatoma cells. Methods : The anti-proliferative effect of taraxerol was investigated by cell counting kit-8 (CCK8) and clonogenic assays. Apoptosis was measured using DAPI, while mitochondrial membrane potential was determined with the aid of rhodamine 123 staining. Protein expression was studied by western blotting. Results : Taraxerol induced concentration-dependent anti-proliferative effects on the middle ear epithelial cholesteatoma cells, and also inhibited their colony formation potential. The drug induced apoptosis in the middle ear epithelial cholesteatoma cells by reducing mitochondrial membrane potential, and also triggered sub-G1 cell cycle arrest in these cells. Moreover, taraxerol inhibited the expression of Nf-kB. Conclusion : These findings reveal that taraxerol may be a potential lead compound for the treatment of middle ear cholesteatoma. Keywords : Cholesteatoma, Epithelial tissues, Taraxerol, Apoptosis, Cell cycle arrest

Alginate Ototoxicity in the Mouse Model.

Objective To determine whether alginate exposure to the round window of the mouse causes any measurable ototoxicity. Study Design Prospective animal study. Setting Basic science laboratory affiliated with a tertiary care university medical center. Subjects and Methods After Institutional Animal Care and Use Committee approval, 5 adult mice were obtained and underwent bullostomy and round window niche application of alginate. Auditory brainstem response (ABR) tests were completed at baseline prior to the procedure and also 5, 14, and 30 days postprocedure. Results were compared. At termination of procedure, the mice were sacrificed with harvest of the cochleae, which were viewed under histologic section. Results There were no significant increases in ABR thresholds in any of the test animals at all test periods after alginate exposure compared to baseline. There were also no observable behavioral changes after the procedure to indicate vestibular dysfunction. Cochlear sectioning revealed no evidence of histologic damage. Conclusion Exposure of alginate to the round window does not cause any obvious ototoxicity in the mouse model. Further clinical trials will be needed to elucidate the effect of alginate in the human middle ear.

Effect of electronic cigarettes on human middle ear

ObjectiveElectronic cigarettes (e-cigarettes) are the most commonly used electronic nicotine delivery systems and are a relatively new product designed for smoking cessation. The market scale of electronic cigarettes is growing rapidly, but the potential impact of e-cigarettes on public health has not yet been verified. In this study, we examined the effect of e-liquids on a human middle ear epithelial cell (HMEEC) line. Material and methodsThe main components of e-liquids are propylene glycol, vegetable glycerin and flavoring agents with or without nicotine. We analyzed 73 bottles of e-liquids from 12 different manufacturers, evaluated the trace elements in e-liquids, and identified the cytotoxicity of e-liquids on HMEECs in the presence or absence of nicotine. ResultsIn the trace elements analysis, nickel, arsenic, cadmium, and lead were detected in the e-liquids. E-liquids without nicotine decreased cell viability, and the average IC 50 value of total e-liquids (n = 73) was 2.48 ± 0.93%. Among the different flavors, menthol-flavored e-liquids significantly reduced cell viability, and their average IC 50 value (n = 28) was 1.85 ± 0.80%. The average IC 50 values were distinct among manufacturers and the proportion of the solvents. ConclusionThe present study provides evidence that e-cigarettes influence and reduce human middle ear cell viability even without the application of nicotine. Additionally, the cytotoxicity of e-liquids was affected by the flavoring agents.

Expression, Distribution, and Role of C-Type Lectin Receptors in the Human and Animal Middle Ear and Eustachian Tube: A Review.

Otitis media (OM) is a group of inflammatory diseases of the middle ear (ME), regardless of cause or pathological mechanism. Among the molecular biological studies assessing the pathology of OM are investigations into the expression of C-type lectin receptors (CLR) in the ME and Eustachian tube (ET). To date, nine studies have evaluated CLR expression in the ME and ET. The expression of individual CLRs in mammalian ME and ET varies by species and model of OM. Assessments have shown that the patterns of CLR expression in the ME and ET vary; that CLR expression may vary by type of OM; and that the distribution and levels of expression of CLRs may depend on the presence or absence of inflammation, with variations even within the same species and same tissue. Infection of the ME and ET with various pathogens is a common cause of all types of OM, with host responses to pathogens mediated initially by the innate immune system. CLRs are important factors in the innate immune system because they act as both adhesion molecules and as pathogen recognition receptors. The expression of CLRs in OM tissues suggests that CLRs are associated with the pathogenesis of various types of OM.

Experimental assessment of miniature accelerometers designed for sensing middle ear motion

Sensing human middle ear motion requires miniature, low-noise sensors to detect low-amplitude vibration of the ossicle bones to replace the external microphone in a cochlear implant system. Specifically, a 35 μg/√Hz sensor resolution is needed measure motion at 500 Hz (Young et al., 2012). Motivated by sensing middle ear motion without irreversible alteration to the ossicular chain, a small, piezoelectric accelerometer is considered. Our detailed low-frequency analytical model is used to identify promising micromachined, piezoelectric bimorph cantilever accelerometer designs. We fabricated a first generation of accelerometers using a conservative microfabrication approach, taken to enhance the yield of devices rather than to minimize the input referred noise (IRN). The mathematical model was validated by voltage actuation testing of these accelerometers. The device sensitivity to acceleration is tested, and the resulting IRN is desired to assess the viability of the sensor for the middle ear motion application. The first generation experimental results are compared to the mathematical model to determine the accuracy of the model and the efficacy of the fabrication methodology. This knowledge will influence future sensor designs optimized for minimal IRN.Sensing human middle ear motion requires miniature, low-noise sensors to detect low-amplitude vibration of the ossicle bones to replace the external microphone in a cochlear implant system. Specifically, a 35 μg/√Hz sensor resolution is needed measure motion at 500 Hz (Young et al., 2012). Motivated by sensing middle ear motion without irreversible alteration to the ossicular chain, a small, piezoelectric accelerometer is considered. Our detailed low-frequency analytical model is used to identify promising micromachined, piezoelectric bimorph cantilever accelerometer designs. We fabricated a first generation of accelerometers using a conservative microfabrication approach, taken to enhance the yield of devices rather than to minimize the input referred noise (IRN). The mathematical model was validated by voltage actuation testing of these accelerometers. The device sensitivity to acceleration is tested, and the resulting IRN is desired to assess the viability of the sensor for the middle ear motion applic...

Analysis of the effect of different patologies on the sound transmission through the middle ear by means of a finite-element model

The middle ear is part of the human auditory system and its function is to transmit acoustical energy to the inner ear by means of mechanical vibrations. Finite-Element (FE) models of the human middle ear have been studied since 90s, making it possible to evaluate its dynamic behavior in different ways. In this work, an accurate FE model of the human middle ear is described and used for assessing the relationship between the reduction of sound transmission through the ossicular chain and hearing loss due to three different pathologies: tympanic membrane perforation, stapedial tendon ossification and stapes fracture. For these three pathologies, case studies from the literature with experimental hearing loss data are reviewed and clinical results are compared to the FE model predictions. In all cases a good relationship between sound transmission reduction predicted by the FE model and the hearing loss measured through audiometric tests were found. Results show that an accurate FE model of the human middle ear can be a powerful tool for clinical applications and research in otology, allowing to predict the effect of middle ear pathologies and to evaluate the results of corrective surgeries on hearing.

A morphometric study of human middle ear ossicles in cadaveric temporal bones of Indian population and a comparative analysis

IntroductionMalleus, Incus and Stapes are the three middle ear ossicles which form an articulated chain and help in conduction of sound from external ear to inner ear. Morphometric study of these ossicles has been going since the early 60s. Although the methods of been changing due to advent of newer technologies and treatments. MethodsWe studied ossicles of 60 temporal bones. The ossicles have been obtained by ‘canal-wall down’ mastoidectomy technique. They have been measured by an open software, Fiji (https://imagej.nih.gov) where the scale was standardized and set to mm (millimeter). ResultsThe mean total length of the malleus is 8.23mm; a mean angle of 128.76°, mean width of the head 2.56mm, and mean length of manubrium is 4.17mm. The mean total length of incus is 7.04mm, mean angle of 97.23°, mean total width of 5.31mm, and mean length of long process is 3.27mm. The mean total height of stapes is 3.44mm; mean width of the footplate is 1.10mm and a mean angle of 51.01°. DiscussionMorphometric data obtained in the present study can be useful for the reconstructive procedures. Preoperative radiological assessment is advised for these small bones. The present study also emphasizes on the future directions where in reconstructive procedures can be improved with the artistic renderings of the blueprints provided, for new prosthetic designs which can be manufactured by using Teflon materials.

Design and development of the human middle ear to examine dynamic responses

The research emphasis on the development of Finite Element (FE) model of the human middle ear (ME) that comprises of the tympanic membrane (TM), three auditory ossicles, various ligament structures, and muscles. Due to the complex geometrical shape, conventional modeling techniques leads to inaccuracy in model morphology. A widely held approach to model such complex biological components is by using micro X-ray computed tomography (μCT). High-resolution 3-Dimensional morphology models of the human ME are published and made available for non-commercial research purpose, but these published models are in form of surface meshes and holds good for visualization purpose and 3-D printing only. To simulate and analyze the dynamic behavior of ME components it is essential to convert these surface meshes (stereolithography files) into volume meshes and hence these geometrical models necessitate further processing. Additionally, an attempt has been made to design and incorporate certain missing geometries to represent a complete ME model. The intent of current study is to develop a resourceful anatomically precise FE model of the human ME which is capable of incorporating variation in parameters and corresponds in view of that.

Effect of Formaldehyde on Human Middle Ear Epithelial Cells.

Formaldehyde (FA) is a familiar indoor air pollutant found in everything from cosmetics to clothing, but its impact on the middle ear is unknown. This study investigated whether FA causes cytotoxicity, inflammation, or induction of apoptosis in human middle ear epithelial cells (HMEECs). Cell viability was investigated using the trypan blue assay and a cell counting kit (CCK-8) in HMEECs treated with FA for 4 or 24 h. The expression of genes encoding the inflammatory cytokine tumor necrosis factor alpha (TNF-α) and mucin (MUC5AC) was analyzed using RT-PCR. Activation of the apoptosis pathway was determined by measuring mitochondrial membrane potential (MMP), cytochrome oxidase, caspase-9/Mch6/Apaf 3, and Caspase-Glo® 3/7 activities. The CCK-8 assay and trypan blue assay results showed a reduction in cell viability in FA-treated HMEECs. FA also increased the cellular expression of TNF-α and MUC5AC and reduced the activities of MMP and cytochrome oxidase. Caspase-9 activity increased in cells stimulated for 4 h, as well as caspase-3/7 activity in cells stimulated for 24 h. The decreased cell viability, the induction of inflammation and mucin gene expression, and the activation of the apoptosis pathway together indicate a link between environmental FA exposure and the development of otitis media.

Numerical research of biomechanical system with SMA prosthesis

In this paper the modelling of special biomechanical mechanism and application of shape memory materials are presented. The model of the human middle ear is made as multibody system. The basic 3dof ear model of the healthy middle ear is modified to represent the damaged ear. A damaged of the ossicular chainis taken into account by adding gap in visco-elastic joints. In addition, an attempt of the ossicles chain reconstruction through prosthesis made of shape memory alloy is presented. Moreover, a new description of the hysteresis sub-loop which characterise prosthesis material is proposed. Finally, dynamic responses of healthy, damaged and reconstructed models of the middle ear are compared by quality index.