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Left Panel: Schematic of the air spaces of the human middle-ear. The tympanic cavity houses the ossicles and is connected to the mastoid air cells and antrum by the tube-like aditus ad antrum. Adapted from Onchi (1961). Middle Panel: Schematic of the measurement setup. The tympanic membrane, malleus, and incus are removed. The sound source and microphone assembly sit in the ear canal with the probe tube of the microphone flush with the entrance to the tympanic cavity and extended about 3 mm from the sound tube. To measure the antrum pressure, a probe tube connected to a microphone sits in the antrum. Right Panel: An analog circuit model schematic of the middle-ear air space (e.g., Zwislocki, 1962; Kringlebotn, 1988; Voss et al., 2000b). The circuit model relates to the ear structure through the location of circuit elements on the structural outline. The voltages are analogous to sound pressures and currents are analogous to volume velocities. The capacitor in the tympanic cavity represents the volume of air in the tympanic cavity, the resistor and inductor within the additus ad antrum represent the tube-like passage, and the capacitor in the antrum represents the volume of air in the antrum and mastoid air cells.
Source publication
The impedance of the middle-ear air space was measured on three human cadaver ears with complete mastoid air-cell systems. Below 500 Hz, the impedance is approximately compliance-like, and at higher frequencies (500-6000 Hz) the impedance magnitude has several (five to nine) extrema. Mechanisms for these extrema are identified and described through...
Contexts in source publication
Context 1
... human middle-ear air space, schematized in Fig. 1 left, consists of the tympanic cavity, aditus ad antrum, the antrum of the mastoid, and the mastoid air cells e.g., Donaldson et al., 1992, p. 151. The tympanic cavity houses the ossicular system and lies between the tympanic membrane and the inner ear. The posterior-superior portion of the tympanic cavity narrows into the passage ...Context 2
... space, including all mastoid air cells, was left intact. Next, the bony ear canal was drilled away so that the tympanic ring was fully exposed. Using an otologicoperating microscope, the tympanic membrane, malleus, and incus were removed with forceps, and the stapes was left in the oval window of the cochlea to prevent leakage of cochlear fluid Fig. 1 middle. In all cases, the ears appeared normal. At this point in the preparation, the ears were refrozen. Several weeks later they were thawed by placing them in a saline-filled container for several hours and measurements were made after they thawed and the saline was suctioned ...Context 3
... mm, which approximated the size of the tympanic rings in our specimens. Any irregular spaces between the ring and the bone were filled with dental cement. When the sound source was coupled to the tympanic ring via the coupling ring, the tip of the probe-tube microphone extension Sec. II C was approximately at the same depth as the tympanic ring Fig. 1 middle. To ensure that the middle-ear was sealed acoustically, much of the specimen was coated with additional dental cement, and the specimen was also placed in the finger of a latex glove that provided a tight fit around it. Prior to making acoustic measurements, suction was applied to both the tympanic cavity and the antrum via the ...Context 4
... circuit models of the middle-ear air space were reviewed by Voss et al. 2000b and are briefly summarized here. The models of Zwislocki 1962, Kringlebotn 1988, and Voss et al. 2000b are designed to represent the structure/function relationship of the middle-ear air space, and a summary of these models is shown in the right panel of Fig. 1. 4 The models employ a capacitor to represent the compliance of air in the tympanic cavity. This capacitor is in parallel with a series resistor-inductor-capacitor connection. The resistor-inductor path represents volume velocity flow through the tube-like additus ad antrum and the capacitor represents the compliance of the air in the ...Context 5
... fit the four-element model Fig. 1 right to the measurements made here using the same procedure outlined by Voss et al. 2000b, which is summarized in the Appendix. Voss et al. 2000b applied this procedure to each of the 11 bones for which Z CAV with an altered mastoid space was measured. Here, we apply the same procedure to the 3 ears for which Z CAV was measured with ...Context 6
... Thus, up to 3000 Hz, the model is a reasonable description of the measured Z CAV . In contrast to the measurements with the altered mastoid, the four-element model is unable to fit the Z CAV measured on ears with unaltered mastoids as well as it fits ears with altered mastoids. The three measurements with Z CAV from the unaltered mastoid state Fig. 4, ears 1, 2, and 3 show that the four-element model is able to represent the Z CAV behavior at the lower frequencies e.g., less than 500 Hz and is able to capture the general behavior of the first minimum in magnitude. However, at frequencies near and above the first minimum in magnitude, the four-element model is unable to capture any of the fine ...Context 7
... summary, the model topology of Fig. 1 right describes the general features of Z CAV for ears with both intact and altered mastoid cavities, but it does not describe all features of the measurements with unaltered mastoids made both here and by Onchi 1961 7 , with the mastoid air-cell tract intact. The three energy-storage elements in the model limit the model to two ...Context 8
... within the middle-ear air space, but they are not detailed precise models of any particular middle-ear air space. In fact, a model of a specific middle-ear air space would most likely be a combination of all three of these model topologies. All three models of Fig. 5 include the four elements C t , M ad , R ad , and C a of the model described in Fig. 1 right, which has been successfully used to represent the impedance of ears with altered mastoids. Figure 5a represents connections between the tympanic cavity and the mastoid air-cell system that are in addition to the aditus ad antrum. Specifically, each series connection between a mass, resistor, and compliance represents a ...Context 9
... use our measurement of H P , the transfer function between the pressures P ANTRUM and P CAV , to characterize the impedance of the antrum and mastoid air-cell system. Specifically, we propose the model topology of Fig. 7 upper, which differs from the previous models i.e., Fig. 1 right in that the antrum and mastoid air-cell system are not represented by a single capacitor but instead by the impedance Z MASTOID . Using the model topology of Fig. 7 upper, a measurement-based estimate for Z MASTOID can be calculated ...Context 10
... 3 , which spans the range of tympaniccavity volumes reported in the literature Gyo et al., 1986;Whittemore et al., 1998 and estimated from model fits Table I. The measurement-based estimate of Z MASTOID Fig. 7 lower is not consistent with the previous modeling approach of representing the antrum and mastoid air-cell system by a single compliance Fig. 1 right. At low frequencies Z MASTOID is compliance dominated, but above about 800 Hz Z MASTOID would be better represented by a model with multiple resonances, such as a combination of the possibilities proposed here in Fig. 5. Above 4000 Hz, our measurementbased estimate of Z MASTOID clearly includes errors, as the angle is less than ...Context 11
... outline the process for determining the values for the four circuit elements C t , M ad , R ad , and C a of the model described in Fig. 1 right. As presented by Voss et al. 2000b, we assume that at low frequencies, the cavity impedance Z CAV can be approximated as a pure compliance C cav which can be calculated from our measurements and used to constrain the compliances C t and C a such ...Context 12
... Zwislocki 1962 middle-ear air space model includes an additional resistor in parallel with the capacitor that represents the tympanic cavity within Fig. 1 right. The additional resistor has been ignored for the discussion here, as it controls the sharpness of the resonances and does not add additional ones. This resistor is further discussed by Voss et al. ...Context 13
... impedance measurement made by Onchi 1961 on a single cadaver middle-ear air space was reproduced here as a magnitude and angle Fig. 2 from the author's representation with a real and imaginary part. The original plot Onchi, 1961, Fig. 10 suggests a noncausal response: Near 3000 Hz the real part of the impedance appears to be forced to maintain a positive value while there is no corresponding abrupt transition in the derivative of the imaginary part of the impedance at this ...Similar publications
Objective
The anatomy of the scalp nerves varies widely with age, race, and individuals of the same race and even within the same individual and hence need to be studied extensively to avoid complications and improve effectiveness during various surgical and anesthetic procedures of the scalp.
Materials and Methods
Gross dissection was carried out...
Citations
... In addition, there was a tendency towards an asymptotic phase shift at 180°, meaning that this was a second order system. Figure 4. Comparison of the three studied finite element models with experimental test [2,38,39] and FEM [29] for the module (A) and phase (B) tympanic membrane impedance (ZTM). Figure 5A shows the module EAC impedance for each of the studied FEMs, which strongly coincided, especially at high frequencies. ...
here are different ways to analyse energy absorbance (EA) in the human auditory system. In previous research, we developed a complete finite element model (FEM) of the human auditory system. In this mentioned work, the external auditory canal (EAC), middle ear, and inner ear (spiral cochlea, vestibule, and semi-circular canals) were modelled based on human temporal bone histological sections. Multiple acoustic, structure and fluid-coupled analyses were conducted using the FEM to perform harmonic analyses in the 0.1–10 kHz range. Once the FEM had been validated with published experimental data, the FEM numerical results were used to calculate the EA or energy reflected (ER) by the tympanic membrane. This EA was also measured in clinical audiology tests which were used as a diagnostic parameter. A mathematical approach was developed to calculate the EA and ER, with numerical and experimental results showing adequate correlation up to 1 kHz. Another published FEM had adapted its boundary conditions to replicate experimental results. Here, we recalculated those numerical results by applying the natural boundary conditions of human hearing and found that the results almost totally agreed with our FEM. This boundary problem is frequent and problematic in experimental hearing test protocols: the more invasive they are, the more the results are affected. One of the main objectives of using FEMs is to explore how the experimental test conditions influence the results. Further work will still be required to uncover the relationship between the middle ear structure and EA to clarify how to best use FEMs. Moreover, the FEM boundary conditions must be more representative in future work to ensure their adequate interpretation.
... Acoustic modelling [13] Formulation of a circuited lumped-element model of the adult middle-ear of human beings for biomechanics, according to the comparisons taken from measuring air-conduction information. ...
This review article attempts to analyze the various research studies conducted in developing the models to
evaluate the anatomy of the middle ear, its biomechanics, and the applications of these models in normal
and diseased states.
Various studies conducted over the past 50-60 years have been critically analyzed. We also discuss the
various advantages and disadvantages of different methods of measurement of middle ear
parameters. Beginning from anatomical modelling to histopathological sections and the latest threedimensional (3D) reconstruction with finite element modelling, various methods of middle ear
measurements have been critically analyzed.
At the end of this review, we have concluded that the best and most effective method of middle ear
modelling is the 3D reconstruction using high-resolution computed tomography and finite element
modelling
... Finally, the mesh was post-processed using MeshLab and SolidWorks to isolate, clean, and simplify it. The measured inner volume of the tympanic cavity of the obtained 3D model is 950 mm 3 , which is consistent with the typical values between 0.5 to 1 cm 3 in the literature [22]. ...
This letter presents a hybrid concentric tube robot which covers the middle ear volume for exhaustive ablation of residual cholesteatoma. The proposed robotic system combines a concentric tube robot and a wrist at the distal end, actuated by a tendon. We first introduce the surgical protocol through two access points (ear canal and few millimeters size hole through the mastoid), then derive the anatomical constraints and specify the robot tasks. Based on the robot model enriched with the optical fiber stiffness and on anatomical constraints, the robot parameters are determined as the ones among discretized sets that provide the maximal volume coverage. Experiments are conducted with a benchtop prototype on a 3D printed middle ear phantom to validate the wrist model with the optical fiber and the robot repeatability assessment. The wrist model achieved an root mean square error (RMSE) of 1.33 deg and R2 = 96.8%. The robot repeatability has an RMSE of 0.7 mm for distance errors and 1.34 - 2.42 - 3.11 deg for the angular ones. We finally demonstrated the ablation of cholesteatoma by the embedded optical fiber on the hybrid concentric tube robot prototype.
... As even pathologies do not significantly change the characteristics above 3 kHz, they cannot be fundamentally caused by the ossicular chain or the tympanic membrane area adjacent to the malleus. This frequency range is rather influenced by the position of the probe in the ear canal as shown in [19] for some temporal bones, and even much more by the tympanic cavity [19], which has increasingly relevant and interindividually highly variable influences on the ER above 1-2 kHz, as seen in [10,20]. Therefore, preparation-related differences in the cavities of temporal bones could explain a substantial part of the large variability of the ER above 3 kHz. ...
... Therefore, preparation-related differences in the cavities of temporal bones could explain a substantial part of the large variability of the ER above 3 kHz. While measurements with sealed cavities show generally more resonances [5,20,21], than measurements with open cavity as in [10], some of the resonances with open cavity are in turn introduced by the openings [22]. ...
Current clinical practice is often unable to identify the causes of conductive hearing loss in the middle ear with sufficient certainty without exploratory surgery. Besides the large uncertainties due to interindividual variances, only partially understood cause-effect principles are a major reason for the hesitant use of objective methods such as wideband tympanometry in diagnosis, despite their high sensitivity to pathological changes.
For a better understanding of objective metrics of the middle ear, this study presents a model that can be used to reproduce characteristic changes in metrics of the middle ear by altering local physical model parameters linked to the anatomical causes of a pathology.
A finite-element model is therefore fitted with an adaptive parameter identification algorithm to results of a temporal bone study with stepwise and systematically prepared pathologies. The fitted model is able to reproduce well the measured quantities reflectance, impedance, umbo and stapes transfer function for normal ears and ears with otosclerosis, malleus fixation and disarticulation. In addition to a good representation of the characteristic influences of the pathologies in the measured quantities, a clear assignment of identified model parameters and pathologies consistent with previous studies is achieved.
The identification results highlight the importance of the local stiffness and damping values in the middle ear for correct mapping of pathological characteristics, and address the challenges of limited measurement data and wide parameter ranges from literature.
The great sensitivity of the model with respect to pathologies indicates a high potential for application in model-based diagnosis.
... To do so, the acoustic impedance at the TM is first approximated to the compressibility effect of the middle ear cavity volume of acoustic compliance C TM . This approximation is reasonable for frequencies below 500 Hz [8,21]. Secondly, the acoustic resistance R h associated with viscous losses in the hole is omitted. ...
The occlusion effect is commonly experienced by in-ear device wearers as an increased loudness sensation of bone-conducted low frequency sounds. A widespread theory proposed by Tonndorf and based on a simplified electro-acoustic model describes the phenomenon as the removal of the open earcanal high-pass filter effect due to a perfect or partial occlusion. However, this filter has not been clearly defined and several ambiguities remain. Revisiting the model, a second order high-pass filter effect for the volume velocity transferred between the earcanal wall and the eardrum is highlighted. This filter remains for partial occlusion but vanishes for perfect occlusion. In the latter case, the volume velocity transferred from the earcanal cavity to the middle ear through the eardrum drastically increases, which explains the predominance of the occluded outer ear pathway on the hearing by bone-conduction at low frequencies.
... The effect of mastoid volume, in an artificial ear (73) and in cadaveric ears (74) is, as expected, most pronounced for the lower frequencies ("combination of multiple resonators"). The net effect of mastoid pneumatization however, where many small air cells are taken into account ("resonator tree"), centers also on the mid-frequencies around 2,000 Hz (75). ...
Seemingly unrelated symptoms in the head and neck region are eliminated when a patch is applied on specific locations on the Tympanic Membrane. Clinically, two distinct patient populations can be distinguished; cervical and masticatory muscle tensions are involved, and mental moods of anxiety or need. Clinical observations lead to the hypothesis of a “Tympanic Resonance Regulating System.” Its controller, the Trigeminocervical complex, integrates external auditory, somatosensory, and central impulses. It modulates auditory attention, and directs it toward unpredictable external or expected domestic and internal sounds: peripherally by shifting the resonance frequencies of the Tympanic Membrane; centrally by influencing the throughput of auditory information to the neural attention networks that toggle between scanning and focusing; and thus altering the perception of auditory information. The hypothesis leads to the assumption that the Trigeminocervical complex is composed of a dorsal component, and a ventral one which may overlap with the concept of “Trigeminovagal complex.” “Tympanic Dissonance” results in a host of local and distant symptoms, most of which can be attributed to activation of the Trigeminocervical complex. Diagnostic and therapeutic measures for this “Tympanic Dissonance Syndrome” are suggested.
... This is, of course, in contrast to a live human patient, where the middle-ear cavity would be closed. Previous work has demonstrated that the middle-ear cavity does make contributions to the impedance at the tympanic membrane of up to 10 dB above 1000 Hz (Stepp and Voss 2005). This can introduce variability in measurements even in live patients given differences that occur in middle-ear cavity anatomy. ...
The effects of middle-ear pathology on wideband acoustic immittance and reflectance at frequencies above 6–8 kHz have not been documented, nor has the effect of such pathologies on the time-domain reflectance. We describe an approach that utilizes sound frequencies as high as 20 kHz and quantifies reflectance in both the frequency and time domains. Experiments were performed with fresh normal human temporal bones before and after simulating various middle-ear pathologies, including malleus fixation, stapes fixation, and disarticulation. In addition to experimental data, computational modeling was used to obtain fitted parameter values of middle-ear elements that vary systematically due to the simulated pathologies and thus may have diagnostic implications. Our results demonstrate that the time-domain reflectance, which requires acoustic measurements at high frequencies, varies with middle-ear condition. Furthermore, the extended bandwidth frequency-domain reflectance data was used to estimate parameters in a simple model of the ear canal and middle ear that separates three major conductive pathologies from each other and from the normal state.
... This observation is based on a general acoustic theory defined by Dallos (1973) and Moore (1981). The role of pneumatic cells for low-frequency amplification in humans was suggested by Onchi (1961), and more recently confirmed by Stepp and Voss (2005). ...
Objectives
We test the effects of body mass and phylogeny on middle ear cavity pneumatization, and the role of pneumatization in hearing function, spanning the anatomical, ecological, and behavioral diversity of nonhuman primates.
Materials and methods
All cavities were segmented in middle ear scans of 96 specimens, from 12 strepsirrhine and 15 haplorhine extant species. We measured the tympanic cavity (TC) separately, and all other middle ear spaces together (MES), calculating the degree of pneumatization with the surface area‐to‐volume ratio. We tested body mass effect with linear regression; we evaluated the phylogenetic signal and selection patterns, using a Kappa statistic test, and Ornstein‐Uhlenbeck models (OU). We investigated the link between pneumatization and hearing sensitivity using phylogenetic regression.
Results
Testing body mass reveals an allometric pattern for both TC and MES dimensions. Degree of pneumatization in MES is dependent on body mass in haplorhines: larger animals have more pneumatized MES. Differences at various taxonomic ranks were observed for MES, while no phylogenetic influence was observed for TC. Infraorder selection patterns are different. Auditory performance is significantly related to degree of pneumatization, indicating that a pneumatized middle ear is associated with better perception of low frequencies.
Discussion
Pneumatization in MES is under differential selective pressure, indicating several optima for this trait. Pneumatization in MES probably modifies hearing sensitivity through pressure regulation mechanisms, auditory bulla size reduction, and frequency modulation. This could explain strepsirrhine adaptation to high‐frequency perception, while haplorhine auditory perception is adapted to a broader sound range, including high and low frequencies.
... This simple model provides a useful description of the EC longitudinal sound field and provides a basis for predictions in real ear canals. cavity (open, closed, reduced) affects the middle-ear input impedance Z ME and the sound pressure transformation from EC to near the TM for forward sound stimulation (e.g., Voss et al., 2000;Keefe et al., 1994;Stepp and Voss, 2005;Lewis and Neely, 2015;Feeney et al., 2017). In the reverse-stimulation case, where a displacement source moves the ossicles and the TM, the EC sound pressure distribution is independent of Z ME (see model description in the Appendix). ...
This work is part of a study of the interactions of ear canal (EC) sound with tympanic membrane (TM) surface displacements. In human temporal bones, the ossicles were stimulated mechanically “in reverse” to mimic otoacoustic emissions (OAEs), and the sound field within the ear canal was sampled with 0.5–2 mm spacing near the TM surface and at more distal locations within the EC, including along the longitudinal EC axis. Sound fields were measured with the EC open or occluded. The reverse-driven sound field near the TM had larger and more irregular spatial variations below 10 kHz than with forward sound stimulation, consistent with a significant contribution of nonuniform sound modes. These variations generally did not propagate more than ∼4 mm laterally from the TM. Longitudinal sound field variations with the EC open or blocked were consistent with standing-wave patterns in tubes with open or closed ends. Relative contributions of the nonuniform components to the total sound pressure near the TM were largest at EC natural frequencies where the longitudinal component was small. Transverse variations in EC sound pressure can be reduced by reducing longitudinal EC sound pressure variations, e.g., via reducing reflections from occluding earplugs.
... Cortisol levels in the perilymph do not increase following intravenous administration of a high dose [6] . This is because the inner ear is an end organ with regards to its blood supply, and it is protected by a blood-labyrinth barrier [7] . Dexamethasone is most widely used due to lack of the adverse reactions in other drugs (Methylprednisolone produces the highest relative concentration in lymphatic fluid, but it often provokes a burning sensation during injection. ...
