An Evaluation of Tympanometric Estimates of Ear Canal Volume

The accuracy of tympanometric estimates of ear canal volume was evaluated by testing the following two assumptions on which the procedure is based: (a) ear canal volume does not change when ear canal pressure is varied, and (b) an ear canal pressure of 200 daPa drives the impedance of the middle ear transmission system to infinity so the immittance measured at 200 daPa can be attributed to the ear canal volume alone. The first assumption was tested by measuring the changes in ear canal volune in eight normal subjects for ear canal pressures between ±400 daPa using a manometric procedure based on Boyle's gas law. The data did not support the first assumption. Ear canal volume changed by a mean of .113 ml over the ±400 daPa pressure range with slightly larger volume changes occurring for negative ear canal pressures than for positive ear canal pressures. Most of the volume change was attributed to movement of the probe and to movement of the cartilaginous walls of the ear canal. The second assumption was tested by comparing estimates of ear canal volume from susceptance tympanograms with a direct measurement of ear canal volume adjusted for changes in volume due to changes in ear canal pressure between +±400 daPa. These data failed to support the second assumption. All tympanometric estimates of ear canal volume were larger than the measured volumes. The largest error (39%) occurred for an ear canal pressure of 200 daPa at 220 Hz, whereas the smallest error (10%) occurred for an ear canal pressure of ±400 daPa at 660 Hz. This latter susceptance value (-400 daPa at 660 Hz) divided lay three is suggested to correct the 220-Hz tympanogram to the plane of the tympanic membrane. Finally, the effects of errors in estimating ear canal volume on static immittance and on tympanometry are discussed.

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Macroscopic description of the external and middle ear of paca (Cuniculus paca Linnaeus, 1766)

Pesquisa Veterinária Brasileira ◽

10.1590/s0100-736x2015000600017 ◽

2015 ◽

Vol 35 (6) ◽

pp. 583-589 ◽

Cited By ~ 3

Author(s):

Leandro L. Martins ◽

Ijanete Almeida-Silva ◽

Maria Rossato ◽

Adriana A.B. Murashima ◽

Miguel A. Hyppolito ◽

...

Keyword(s):

Tympanic Membrane ◽

Middle Ear ◽

Gross Anatomy ◽

Experimental Models ◽

Temporal Region ◽

External Ear ◽

Wild Animals ◽

Ear Canal ◽

Macroscopic Description ◽

Mouse Ear

Abstract: Paca (Cuniculus paca), one of the largest rodents of the Brazilian fauna, has inherent characteristics of its species which can conribute as a new option for animal experimantation. As there is a growing demand for suitable experimental models in audiologic and otologic surgical research, the gross anatomy and ultrastructural ear of this rodent have been analyzed and described in detail. Fifteen adult pacas from the Wild Animals Sector herd of Faculdade de Ciências Agrárias e Veterinárias, Unesp-Jaboticabal, were used in this study. After anesthesia and euthanasia, we evaluated the entire composition of the external ear, registering and ddescribing the details; the temporal region was often dissected for a better view and detailing of the tympanic bulla which was removed and opened to expose the ear structures analyzed mascroscopically and ultrastructurally. The ear pinna has a triangular and concave shape with irregular ridges and sharp apex. The external auditory canal is winding in its path to the tympanic mebrane. The tympanic bulla is is on the back-bottom of the skull. The middle ear is formed by a cavity region filled with bone and membranous structures bounded by the tympanic membrane and the oval and round windows. The tympanic membrane is flat and seals the ear canal. The anatomy of the paca ear is similar to the guinea pig and from the viewpoint of experimental model has major advantages compared with the mouse ear.

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External ear canal cholesteatoma after ventilation tube insertion and mastoidectomy

Vojnosanitetski pregled ◽

10.2298/vsp1204363d ◽

2012 ◽

Vol 69 (4) ◽

pp. 363-366 ◽

Cited By ~ 1

Author(s):

Dragoslava Djeric ◽

Milan Jovanovic ◽

Ivan Baljosevic ◽

Srbislav Blazic ◽

Milanko Milojevic

Keyword(s):

Tympanic Membrane ◽

Middle Ear ◽

Membrane Surface ◽

Tube Placement ◽

External Ear ◽

Ventilation Tube ◽

Ear Canal ◽

Tube Insertion ◽

Tissue Mass ◽

External Ear Canal

Introduction. Etiopathogenetically, there are two types of chollesteatomas: congenital, and acquired. Numerous theories in the literature try to explain the nature of the disease, however, the question about cholesteatomas remain still unanswered. The aim of the study was to present a case of external ear canal cholesteatoma (EEC) developed following microsurgery (ventilation tube insertion and mastoidectomy), as well as to point ant possible mechanisms if its development. Case report. A 16-yearold boy presented a 4-month sense of fullness in the ear and otalgia on the left side. A year before, mastoidectomy and posterior atticotomy were performed with ventilation tube placement due to acute purulent mastoiditis. Diagnosis was based on otoscopy examination, audiology and computed tomography (CT) findings. CT showed an obliterative soft-tissue mass completely filled the external ear canal with associated erosion of subjacent the bone. There were squamous epithelial links between the canal cholesteatoma and lateral tympanic membrane surface. They originated from the margins of tympanic membrane incision made for a ventilation tube (VT) insertion. The position of VT was good as well as the aeration of the middle ear cavity. The tympanic membrane was intact and of normal appearance without middle ear extension or mastoid involvement of cholesteatoma. Cholesteatoma and ventilation tube were both removed. The patient recovered without complications and shortly audiology revealed hearing improving. Follow-up 2 years later, however, showed no signs of the disease. Conclusion. There could be more than one potential delicate mechanism of developing EEC in the ear with VT insertion and mastoidectomy. It is necessary to perform routine otologic surveillance in all patients with tubes. Affected ear CT scan is very helpful in showing the extent of cholesteatoma and bony defects, which could not be assessed by otoscopic examination alone.

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Ear microbiota and middle ear disease: a longitudinal pilot study of Aboriginal children in a remote south Australian setting

BMC Microbiology ◽

10.1186/s12866-022-02436-x ◽

2022 ◽

Vol 22 (1) ◽

Author(s):

Steven L. Taylor ◽

Lito E. Papanicolas ◽

Alyson Richards ◽

Furdosa Ababor ◽

Wan Xian Kang ◽

...

Keyword(s):

Tympanic Membrane ◽

Middle Ear ◽

Clinical Signs ◽

South Australia ◽

Tympanic Membrane Perforation ◽

Time Interval ◽

Ear Canal ◽

Upper Respiratory Infection ◽

Australian Community ◽

Aboriginal Children

Abstract Background Otitis media (OM) is a major disease burden in Australian Aboriginal children, contributing to serious long-term health outcomes. We report a pilot analysis of OM in children attending an outreach ear and hearing clinic in a remote south Australian community over a two-year period. Our study focuses on longitudinal relationships between ear canal microbiota characteristics with nasopharyngeal microbiota, and clinical and treatment variables. Results Middle ear health status were assessed in 19 children (aged 3 months to 8 years) presenting in remote western South Australia and medical interventions were recorded. Over the two-year study period, chronic suppurative OM was diagnosed at least once in 7 children (37%), acute OM with perforation in 4 children (21%), OM with effusion in 11 children (58%), while only 1 child had no ear disease. Microbiota analysis of 19 children (51 sets of left and right ear canal swabs and nasopharyngeal swabs) revealed a core group of bacterial taxa that included Corynebacterium, Alloiococcus, Staphylococcus, Haemophilus, Turicella, Streptococcus, and Pseudomonas. Within-subject microbiota similarity (between ears) was significantly greater than inter-subject similarity, regardless of differences in ear disease (p = 0.0006). Longitudinal analysis revealed changes in diagnosis to be associated with more pronounced changes in microbiota characteristics, irrespective of time interval. Ear microbiota characteristics differed significantly according to diagnosis (P (perm) = 0.0001). Diagnoses featuring inflammation with tympanic membrane perforation clustering separately to those in which the tympanic membrane was intact, and characterised by increased Proteobacteria, particularly Haemophilus influenzae, Moraxella catarrhalis, and Oligella. While nasopharyngeal microbiota differed significantly in composition to ear microbiota (P (perm) = 0.0001), inter-site similarity was significantly greater in subjects with perforated tympanic membranes, a relationship that was associated with the relative abundance of H. influenzae in ear samples (rs = − 0.71, p = 0.0003). Longitudinal changes in ear microbiology reflected changes in clinical signs and treatment. Conclusions Children attending the ear and hearing clinic in a remote Aboriginal community present with a broad spectrum of OM conditions and severities, consistent with other remote Aboriginal communities. Ear microbiota characteristics align with OM diagnosis and change with disease course. Nasopharyngeal microbiota characteristics are consistent with the contribution of acute upper respiratory infection to OM aetiology.

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2D Modeling of the Human Ear Using the Equivalent Mechanical Impedance

The European Physical Journal Applied Physics ◽

10.1051/epjap/2020200226 ◽

2020 ◽

Author(s):

Chahbi Aziz ◽

Assif Safaa ◽

Faiz Adil ◽

Hajjaji Abdelowahed.

Keyword(s):

Tympanic Membrane ◽

Middle Ear ◽

Sound Pressure ◽

Mechanical Impedance ◽

Ossicular Chain ◽

Body Parts ◽

Frequency Range ◽

Ear Canal ◽

Finite Elements Analysis ◽

Human Tympanic Membrane

Several mass–spring–damper models have been developed to study the response of the human body parts. In such models, the lumped elements represent the mass of different body parts, and stiffness and damping properties of various tissues. The aim of this research is to develop a 2D axisymmetric model to simulate the motion of the human tympanic membrane. In this contribution we develop our model using a Comsol Multiphysics software to construct a 2D axisymmetric objects, the acoustic structure interaction between the ear canal (field of propagation of the acoustic wave) and the structure of ear (skin, cartilage, bone, tympanic membrane) was solved using finite elements analysis (FEA). A number of studies have investigated the motion of the human tympanic membrane attached to the ossicular chain and the middle ear cavity. While, in our model the tympanic annular is assumed to be fixed and the loading of what comes behind the tympanic membrane as the ossicular chain, middle ear cavity and cochlea were replaced by the equivalent mechanical impedance of a spring mass damper system. The obtained results demonstrate that the maximum displacements of the umbo are obtained at the frequency range of [0.9 - 2.6] kHz, the sound pressure gain had the shape of peak with a maximum at [2 – 3] kHz frequency range. The umbo displacement depends on the damping coefficient d, and the sound pressure at the tympanic membrane was enhanced compared to that at the ear canal entrance.

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Expression of Cytokeratins 13 and 16 in Middle Ear Cholesteatoma

Otolaryngology ◽

10.1177/019459989411000309 ◽

1994 ◽

Vol 110 (3) ◽

pp. 310-317 ◽

Cited By ~ 12

Author(s):

Hiroyuki Sasaki ◽

Cheng-Chun Huang

Keyword(s):

Tympanic Membrane ◽

Middle Ear ◽

Basal Layer ◽

External Ear ◽

Ear Canal ◽

Suprabasal Layer ◽

External Ear Canal ◽

Cytokeratin Expression ◽

Middle Ear Cholesteatoma ◽

Cytokeratin 13

The accumulation of keratinizing epithelium in the middle ear cavity is a crucial factor in the pathogenesis of cholesteatoma. We hypothesize that keratinocytes from the skin of the ear canal migrate and hyperprollferate in response to Inflammation in the middle ear cavity to cause accumulation of keratin debris. In the present study, we Investigated the expression of specific cytokeratins (CKs) in the cholesteatoma matrix to determine whether cholesteatoma is a hyperproliferative disease. Cytokeratin expression was examined in cholesteatoma, meatal skin, and tympanic membrane with two monoclonal antibodies, one for both cytokeratins 13 and 16 (antibody K8.12), and another for cytokeratin 13 only (antibody K5–1A3). CK 13 (MW 51 KD) Is a marker of differentiation and CK 16 (MW 48 KD) is a marker of hyperproliferatlon of keratinocytes. The use of immunoblot probes showed that CKs 13 and 16 were present in cholesteatoma. Immunofluorescenf staining showed the presence of CK 16 In the suprabasal layer of cholesteatoma, which was located near the external ear canal. CK 16 was also localized in the suprabasal layer of meatal skin and tympanic membrane. CK 13 was localized in the basal layer of the cholesteatoma, distal to the external ear canal, but not in the meatal skin and tympanic membrane. Taken together, the present data suggest that cholesteatoma is a hyperprollferative disease and that cholesteatoma expresses CK 16 near the external ear canal and transforms to express CK 13 during growth distally.

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Tympanometric Changes at 226 Hz and 678 Hz Across 10 Trials and for Two Directions of Ear Canal Pressure Change

Journal of Speech Language and Hearing Research ◽

10.1044/jshr.2702.257 ◽

1984 ◽

Vol 27 (2) ◽

pp. 257-266 ◽

Cited By ~ 26

Author(s):

Richard H. Wilson ◽

Janet E. Shanks ◽

Susan K. Kaplan

Keyword(s):

Young Adults ◽

Middle Ear ◽

Peak Pressure ◽

Pressure Change ◽

Transmission System ◽

Ear Canal ◽

Acoustic Admittance ◽

Pressure Peak ◽

The Mean

The influence that repeated tympanometric trials have on the aural-acoustic admittance characteristics of the middle-ear transmission system was studied in 24 young adults. The 226-Hz and 678-Hz data were generated by concurrently digitizing the conductance and admittance tympanograms at 25 daPa/s for both ascending and descending pressure directions. Ten successive trials for each frequency and direction of pressure change were made. Changes in admittance corrected for ear canal volume across the 10 tympanometrie trials were computed. The results demonstrated that generally admittance increases as the number of trials increases. For many subjects, the complexity of the tympanometric configuration also increases across trials. The results from eight subjects with single-peaked 678-Hz tympanograms were compared with the results from eight subjects with notched 678-Hz tympanograms to explain the mean decrease in susceptance across tympanometric trials. Finally, the pressure peak locations of the conductance, susceptance, and admittance tympanograms were evaluated and are discussed. The effects that differences in peak pressure location have on the computed static admittance values are presented.

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Effects of External Ear Canal Pressure on the Middle-Ear Muscle Reflex Threshold

Journal of Speech and Hearing Research ◽

10.1044/jshr.1703.526 ◽

1974 ◽

Vol 17 (3) ◽

pp. 526-530 ◽

Cited By ~ 3

Author(s):

Frederick N. Martin ◽

Sherry Coombes

Keyword(s):

Tympanic Membrane ◽

Middle Ear ◽

External Auditory Canal ◽

Acoustic Impedance ◽

Normal Hearing ◽

Air Pressure ◽

External Ear ◽

Ear Canal ◽

Acoustic Reflex ◽

Reflex Threshold

Twenty normal-hearing individuals served as subjects in an experiment designed to determine the relationships between positive and negative air pressure in the external auditory canal and the intensity required to elicit the acoustic reflex. Pressure was varied from +240 to −240 mm H 2 O. Changes in the magnitude of acoustic impedance were measured on an acoustic impedance meter and displayed graphically on a Y-T recorder. As air pressure was varied in the canal and the tympanic membrane was displaced from its position of greatest compliance, systematic increases in the intensity required to elicit the reflexes were noted. The magnitude of the differences was smaller than might have been anticipated, not exceeding a mean of 5.1 dB at −240 mm H 2 O.

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Does occurrence of keratinizing stratified squamous epithelium in the middle-ear cavity always indicate a cholesteatoma?

The Journal of Laryngology & Otology ◽

10.1258/0022215042450805 ◽

2004 ◽

Vol 118 (10) ◽

pp. 757-763 ◽

Cited By ~ 2

Author(s):

Lars-Eric Stenfors

Keyword(s):

Tympanic Membrane ◽

Middle Ear ◽

Squamous Epithelium ◽

External Ear ◽

Defence Mechanism ◽

Ear Canal ◽

Non Invasive ◽

Tympanic Membrane Perforations ◽

Acquired Cholesteatoma ◽

Stratified Squamous Epithelium

The origin and behaviour of keratinizing stratified squamous epithelium, anessential component of cholesteatoma occurring in the middle-ear cavity, has puzzled otologistsfor decades. In this experimental study in 16 cats, central (n = 23) and peripheral (n = 9) tympanic membrane perforations were observed for up to 63 days before sacrifice. The tympanic membranes with bony rim were excised, decalcified and embedded in Epon 812. Sections werestained with toluidine blue and examined using a light microscope. The perforation had been sealed by meatal epithelium exhibiting pronounced hyperplasia and keratin formation, lying on abedof granulation tissue. Subtotal central perforations healed within 14 days, forming a bowl-shaped tympanic membrane and leaving parts of the handle of the malleus (with meatal epithelium) protruding freely into the middle-ear cavity. Stratified squamous epithelium, morphologicallyidentical with that of external ear canal epidermis, could be observed on the malleus even 63 days after operation. This meatal epithelium was non-keratinizing, non-invasive, and showed no destructive properties typical of acquired cholesteatoma. During certain circumstances, the cellcycle of hyperplastic epidermal epithelium within the middle-ear cavity can evidently be arrested and inactivated by a local defence mechanism.

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The Effect of Stapedectomy on the Loudness of One’s Own Voice

Journal of Speech and Hearing Research ◽

10.1044/jshr.0803.223 ◽

1965 ◽

Vol 8 (3) ◽

pp. 223-234 ◽

Cited By ~ 1

Author(s):

William Melnick

Keyword(s):

Middle Ear ◽

Normal Subjects ◽

Sound Energy ◽

Loudness Function ◽

Before And After ◽

Increased Sensitivity

Five subjects with normal middle ear mechanisms, and otosclerotic patients, before and after stapedectomy, matched the loudness of their voices to the loudness of a 125-cps-sawtooth noise. The results showed loudness matching functions with gradual slopes, less than 1.00, for the normal subjects and the patients prior to stapedectomy. Post-surgically, the loudness function for the patients increased in steepness to considerably more than 1.00. These results are explained, most logically, in terms of increased sensitivity of the altered middle ear to sound energy generated by the listener’s own voice.

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