Model Of Human Middle Ear Research Articles

Assessment of hearing loss induced by tympanic membrane perforations under blast environment.

This study provides an approach to estimating tympanic membrane perforation-induced hearing loss (HL) using a human middle ear model. Sixty-one cases of tympanic membrane perforation originating from fireworks were reported from the Ear-Nose-Throat Department. The otoscope, audiometry data and diagnosis records were organized, and gender, age, etiology, perforation size and diseased ear side were classified as independent variables. A multinomial regression model was used to analyze the potential effects of the variables on HL. Meanwhile, a human middle ear model was implemented to calculate the ensued HL resulting from different perforation areas and sites. In addition, linear regression models were used to establish functions between perforation size and HL. The audiometry data indicate that HL at high frequencies (f > 2kHz) is much more profound than that at the speech frequency band (f < 1kHz). Compared with mild HL (<15dB), mediate HL (15-30dB) was correlated with the perforation area (p < 0.05, 95% CI), while severe HL (>30dB) was affected by both perforation size and age (p < 0.05, 95% CI). However, other factors, including gender and diseased ear side, do not show a statistically significant effect on HL. Furthermore, the Kruskal-Wallis test result reveals that HL at frequencies of 0.25 kHz ≤ f ≤ 8kHz is strongly associated with the perforation size (p < 0.05, 95% CI). It is conclusive that HL is positively proportional to the perforation size. However, HL is not correlated with the perforation site for small perforation areas of < 10% (p > 0.05, 95% CI).

Assessment methodology for pressure-related aural discomfort in high-speed trains using airtightness experiments and mathematical models

This study aimed at establishing an evaluation methodology for aural discomfort induced by the interior pressure changes in high-speed trains running in tunnels. Experiments in pressure cabin, which can reveal the relationship between aural discomfort and pressure change, were discussed. Furthermore, a human middle ear model was used to simulate the vibration. The experimental conditions were considered as pressure loads, which were exerted on the tympanic membrane. Furthermore, the aural discomfort was hierarchically divided into four levels: ideal, good, bad, and worse. Four indicators, such as the tympanic membrane displacement and stress and the stapes footplate displacement and velocity, were used to establish the discomfort criteria. Logistic regression analysis was used to investigate the incidences of each level as well as to obtain the thresholds between levels. The outcomes have a p-value of less than 0.05; hence, the response results of the indicators are statistically significant. Additionally, the thresholds of the indicators were obtained and used to differentiate the aural discomfort levels. The intervals of the four indicators are (0,T1), (T1,Tc), (Tc,T3), and (T3,&gt;T3) for the discomfort levels of ideal, good, bad, and worse, respectively. Moreover, the onset mechanism of aural sensations was revealed using the four indicators. It can be implied that large tympanic membrane and stapes footplate displacements tend to elicit ear complaints, such as fullness, otalgia, and vertigo, whereas the large stapes footplate velocity affects the onset of tinnitus and hearing loss.

A study on the effect of ligament and tendon detachment on human middle ear sound transfer using mathematic model.

The objective of this study is to investigate the effects of ligament and tendon detachment on human middle ear sound transfer. For this purpose, a geometric human middle ear model was reconstructed based on the computed tomography scanning data of the temporal bones from healthy adult volunteers. For the ear model, pars tensa was assumed to be fit for a 5-parameter Maxwell model and inverse method was used to obtain the necessary coefficients. Furthermore, frequency response method was implemented to investigate the vibration behaviors of tympanic membrane umbo and stapes footplate under an acoustic stimulus of 90 dB within 0.2-8 kHz. Meanwhile, nine patterns of fractured ligaments and tendons, whose effects on the middle ear sound transfer function were simulated by setting free the nodes of the ligaments and tendons of interest. The results indicate that the displacement of tympanic membrane umbo and stapes footplate as well as the velocity transfer function lies within the bounds of the published experimental data. The detachments of ligaments or tendons except for lateral mallear ligament may incur both gains as much as 15 dB and losses of -8 dB in the velocity of stapes footplate at low frequencies (f≤ 1 kHz), while no significant changes were observed at high frequencies (f > 1 kHz). However, detachment of the ligaments or tendons induces tiny changes in the displacement of stapes footplate at the frequencies of 0.2-8 kHz.

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.`

Research on effecting mechanism of environmental parameters on human ear

Sound and air pressure both have an important effect on the ear of human beings. In this paper, we established the finite element model of human middle ear to study the sound transmission mechanism and the stress of human ear under the three conditions of acoustic environment, low pressure acoustic environment and pressure fluctuation environment. Experiment and theoretical calculation were also done in the analysis process. The results show that the surface state of the tympanic membrane can reflect the human auditory sensation to a certain extent. Low pressure can reduce the acoustic energy into human ear, and pressure fluctuation leads the ear to bear great stress and temporary hearing loss. In this paper, the quantification of some objective factors is of great significance to the optimization of some standards and the decoupling of multi environmental effects.

A Functional 3D Printed Human Middle Ear Model

A Functional 3D Printed Human Middle Ear Model

Human middle-ear model with compound eardrum and airway branching in mastoid air cells.

An acoustical/mechanical model of normal adult human middle-ear function is described for forward and reverse transmission. The eardrum model included one component bound along the manubrium and another bound by the tympanic cleft. Eardrum components were coupled by a time-delayed impedance. The acoustics of the middle-ear cleft was represented by an acoustical transmission-line model for the tympanic cavity, aditus, antrum, and mastoid air cell system with variable amounts of excess viscothermal loss. Model parameters were fitted to published measurements of energy reflectance (0.25-13 kHz), equivalent input impedance at the eardrum (0.25-11 kHz), temporal-bone pressure in scala vestibuli and scala tympani (0.1-11 kHz), and reverse middle-ear impedance (0.25-8 kHz). Inner-ear fluid motion included cochlear and physiological third-window pathways. The two-component eardrum with time delay helped fit intracochlear pressure responses. A multi-modal representation of the eardrum and high-frequency modeling of the middle-ear cleft helped fit ear-canal responses. Input reactance at the eardrum was small at high frequencies due to multiple modal resonances. The model predicted the middle-ear efficiency between ear canal and cochlea, and the cochlear pressures at threshold.

Finite element model of human ear reconstruction through micro-computer tomography

Conclusions: The validated finite element model of human middle ear can be used as a tool in hearing loss research. Objective: To establish an accurate finite element model of the external ear canal and middle ear through micro-computer tomography and test its feasibility in the human. Methods: A fresh specimen of human temporal bone was scanned by micro-computer tomography. The finite element model was established based on the images, and then the simulation results were compared with published experimental data. Results: After a series of simulations were conducted, the simulated results were compatible with the published experimental data and this confirms the validation of the finite element model.

Design of Floating Mass Type Piezoelectric Actuator for Implantable Middle Ear Hearing Devices

To overcome some of the problems inherent in conventional hearing aids such as low gain at high frequencies due to acoustic feedback, discomfort in occlusion of the external ear canal and so on, implantable middle ear hearing devices (IMEHDs) have been developed over the past two decades. For such kinds of IMEHDs, this paper presents the design of a floating mass piezoelectric actuator using a PMN-30%PT stack as a new type of vibrator. The proposed piezoelectric actuator consists of only three components of a piezoelectric stack, a metal case and a clamp. For the purpose of aiding the design of this actuator, a coupling biomechanics model of human middle ear and the piezoelectric actuator was constructed. This model was built based on a complete set of computerized tomography section images of a healthy volunteer’s left ear by reverse engineering technology. The validity of this model was confirmed by comparing the motion of the tympanic membrane and stapes footplate obtained by this model with published experimental measurements on human temporal bones. It is shown that the designed actuator can be implanted on the incus long process by a simple surgical operation, and the stapes footplate displacement by its excitation at 10.5 V root-mean-square(RMS) voltage was equivalent to that from acoustic stimulation at 100 dB sound pressure level(SPL), which is adequate stimulation to the ossicular chain. The corresponding power consumption is 0.04 mW per volt of excitation at 1 kHz, which is low enough for the transducer to be used in an implantable middle ear device.