-
Journal of Comparative Physiology. A,... Sep 2020The sheep middle ear has been used in training to prepare physicians to perform surgeries and to test new ways of surgical access. This study aimed to (1) collect... (Comparative Study)
Comparative Study
The sheep middle ear has been used in training to prepare physicians to perform surgeries and to test new ways of surgical access. This study aimed to (1) collect anatomical data and inertial properties of the sheep middle-ear ossicles and (2) explore effects of these features on sound transmission, in comparison to those of the human. Characteristic dimensions and inertial properties of the middle-ear ossicles of White-Alpine sheep (n = 11) were measured from high-resolution micro-CT data, and were assessed in comparison with the corresponding values of the human middle ear. The sheep middle-ear ossicles differed from those of human in several ways: anteroinferior orientation of the malleus handle, relatively small size of the incus with a relatively short distance to the lenticular process, a large area of the articular surfaces at the incudostapedial joint, and a relatively small moment of inertia along the anterior-posterior axis. Analysis in this study suggests that structure and orientation of the middle-ear ossicles in the sheep are conducive to an increase in the hinge-like ossicular-lever-action around the anterior-posterior axis. Considering the substantial anatomical differences, outcomes of middle-ear surgeries would presumably be difficult to assess from experiments using the sheep middle ear.
Topics: Animals; Ear Ossicles; Ear, Middle; Hearing; Humans; Incus; Malleus; Sheep
PubMed: 32564138
DOI: 10.1007/s00359-020-01430-w -
The Journal of Experimental Biology Nov 2022In most anuran amphibians, acoustic communication is of prime importance for mate localization and selection. The tympanic middle ear increases auditory sensitivity and...
In most anuran amphibians, acoustic communication is of prime importance for mate localization and selection. The tympanic middle ear increases auditory sensitivity and directionality and is therefore expected to be favoured by natural selection. However, especially within the family of true toads (Bufonidae) there is a tendency for species to lose parts of the middle ear apparatus and consequently have a reduced sensitivity to high-frequency sounds (above 1 kHz). Part of the explanation for this may be that development of the middle ear is especially slow in bufonids, and thus the middle ear would be more likely to be lost or non-functional in paedomorphic species. However, a timeline of development of the middle ear has not been established previously. The goal of the present study was to investigate middle ear development in a toad species that has a well-known natural history and acoustic communication behaviour. We made a detailed study of anatomy and biophysics of the middle ear with measurements of auditory sensitivity across age in post-metamorphic natterjack toads (Epidalea calamita). The tadpoles and toadlets were raised in the laboratory, so their exact age was known, their auditory sensitivity was measured using auditory brainstem responses, and middle ear development and function were assessed by anatomical studies and laser vibrometry. We found that the developmental stage of the middle ear depends on the size of the toad rather than its age. The middle ear was functional at the earliest at a snout-vent length of 40 mm, which for these toads was around 500 days post-metamorphosis, close to the time of first reproduction. The functional, adult-like middle ear was shown to have 30 dB increased sensitivity to the dominant frequency of the mating call compared with sensitivities measured in newly metamorphosed individuals.
Topics: Humans; Animals; Bufonidae; Ear, Middle; Tympanic Membrane; Larva; Metamorphosis, Biological
PubMed: 36268787
DOI: 10.1242/jeb.244759 -
Scientific Reports Oct 2022Human temporal bone specimens are used in experiments measuring the sound transfer of the middle ear, which is the standard method used in the development of active and...
Human temporal bone specimens are used in experiments measuring the sound transfer of the middle ear, which is the standard method used in the development of active and passive middle ear implants. Statistical analyses of these experiments usually require that the TB samples are representative of the population of non-pathological middle ears. Specifically, this means that the specimens must be mechanically well-characterized. We present an in-depth statistical analysis of 478 data sets of middle ear transfer functions (METFs) from different laboratories. The data sets are preprocessed and various contributions to the variance of the data are evaluated. We then derive a statistical range as a reference against which individual METF measurements may be validated. The range is calculated as the two-sided 95% tolerance interval at audiological frequencies. In addition, the mean and 95% confidence interval of the mean are given as references for assessing the validity of a sample group. Finally, we provide a suggested procedure for measuring METFs using the methods described herein.
Topics: Ear, Middle; Humans; Ossicular Prosthesis; Sound; Temporal Bone
PubMed: 36241675
DOI: 10.1038/s41598-022-21245-w -
Journal of Anatomy Feb 2016Anatomists and zoologists who study middle ear morphology are often interested to know what the structure of an ear can reveal about the auditory acuity and hearing... (Review)
Review
Anatomists and zoologists who study middle ear morphology are often interested to know what the structure of an ear can reveal about the auditory acuity and hearing range of the animal in question. This paper represents an introduction to middle ear function targetted towards biological scientists with little experience in the field of auditory acoustics. Simple models of impedance matching are first described, based on the familiar concepts of the area and lever ratios of the middle ear. However, using the Mongolian gerbil Meriones unguiculatus as a test case, it is shown that the predictions made by such 'ideal transformer' models are generally not consistent with measurements derived from recent experimental studies. Electrical analogue models represent a better way to understand some of the complex, frequency-dependent responses of the middle ear: these have been used to model the effects of middle ear subcavities, and the possible function of the auditory ossicles as a transmission line. The concepts behind such models are explained here, again aimed at those with little background knowledge. Functional inferences based on middle ear anatomy are more likely to be valid at low frequencies. Acoustic impedance at low frequencies is dominated by compliance; expanded middle ear cavities, found in small desert mammals including gerbils, jerboas and the sengi Macroscelides, are expected to improve low-frequency sound transmission, as long as the ossicular system is not too stiff.
Topics: Acoustic Impedance Tests; Animals; Ear, Middle; Hearing; Mammals; Models, Biological
PubMed: 26100915
DOI: 10.1111/joa.12316 -
Diving and Hyperbaric Medicine Dec 2020During descent in freediving there is exposure to rapidly increasing pressure. Inability to quickly equalise middle ear pressure may cause trauma to the ear. This study...
INTRODUCTION
During descent in freediving there is exposure to rapidly increasing pressure. Inability to quickly equalise middle ear pressure may cause trauma to the ear. This study aimed to evaluate the occurrence of pressure-related damage to the middle ear and the Eustachian tube during freediving and to identify possible risk factors.
METHODS
Sixteen free divers performed diving sessions in an indoor pool 20 metres' freshwater (mfw) deep. During each session, each diver performed four own free dives and up to four safety dives. Naso- and oto-endoscopy and Eustachian tube function tests were performed on the right and left ears before diving, between each session and after the last session. The otoscopic findings were classified according to the Teed classification (0 = normal tympanic membrane to 4 = perforation). Additionally, ENT-related complaints were assessed using a questionnaire.
RESULTS
Participants performed 317 dives (on average 20 dives per diver, six per session). The average depth was 13.3 mfw. Pressure-related changes (Teed 1 and 2) were detected in 48 % of ears. Teed level increased significantly with an increasing number of completed sessions (P < 0.0001). Higher pressure-related damage (Teed 2) occurred in less experienced divers, was associated with significantly lower peak pressures in the middle ear and led to more ear-related symptoms. A preference for the Frenzel technique for middle ear pressure equalisation during freediving was shown.
CONCLUSIONS
Pressure exposure during freediving had a cumulative effect on the middle ear. Factors such as diving depth, diving experience and number of diving sessions correlated with the occurrence of higher Teed levels.
Topics: Barotrauma; Diving; Ear, Middle; Eustachian Tube; Humans; Otoscopy
PubMed: 33325015
DOI: 10.28920/dhm50.4.350-355 -
Current Medical Imaging 2023Teratoma is a true neoplasm composed of a number of different types of tissue derived from the three germinal layers but rarely occurs in the middle ear (ME). The...
BACKGROUND
Teratoma is a true neoplasm composed of a number of different types of tissue derived from the three germinal layers but rarely occurs in the middle ear (ME). The features of middle ear teratomas (MET) have not been well described.
OBJECTIVE
The objective of this study is to explore the clinical and imaging features of MET, and report 2 rare cases of MET with ear malformation that have never been reported.
MATERIALS AND METHODS
The clinical, CT and MRI data of 8 patients with a pathological diagnosis of MET were collected and retrospectively mined, and 14 patients with MET reported in previous literature were also reviewed.
RESULTS
① Female, left ear predominance in MET, and the most common symptoms were otorrhea and hearing loss. ② On CT and MRI, the MET presented as an irregular soft tissue mass that was heterogeneous, with fatty tissue and involved multiple sites, and the ET and tympanum were correspondingly expanded and locally destroyed. ③ Mictotia with MET in two patients was presented, which was the first report.
CONCLUSION
MET has female sex and left ear predominance. CT and MRI can be used to diagnose MET and display its extent and its relationship to the carotid canal in detail. Complete surgical excision is the definitive treatment.
Topics: Humans; Female; Retrospective Studies; Ear Neoplasms; Ear, Middle; Teratoma; Magnetic Resonance Imaging
PubMed: 36650647
DOI: 10.2174/1573405619666230117140658 -
The British Journal of Radiology May 2020Active middle ear implants augment sound waves and directly stimulate the middle ear structures. The most frequently utilised active middle ear implant is the Vibrant... (Review)
Review
Active middle ear implants augment sound waves and directly stimulate the middle ear structures. The most frequently utilised active middle ear implant is the Vibrant Soundbridge (VSB).CT plays a vital role in appropriate patient selection and surgical planning of active middle ear implant surgery. The VSB offers a number of options for implant placement. The ideal location is influenced by the patient's middle ear and mastoid anatomy as well as the type and severity of the hearing loss. CT provides important information on the surgical access to the middle ear and helps determine the most appropriate implant site by assessing the adjacent middle ear anatomy and the continuity of the ossicular chain. Post-operative active middle ear implant imaging may be indicated in the setting of poor auditory outcomes and when revision surgery is being considered so as to assess for suboptimal implant placement or migration.This pictorial review will describe the VSB middle ear device and explain the role of imaging in both the pre-operative and post-operative settings.
Topics: Adult; Checklist; Ear, Middle; Hearing Loss; Humans; Ossicular Prosthesis; Patient Care Planning; Postoperative Care; Preoperative Care; Prosthesis Design; Sound; Tomography, X-Ray Computed; Vibration
PubMed: 31944820
DOI: 10.1259/bjr.20190741 -
Cell Communication and Signaling : CCS Sep 2022Middle ear cholesteatoma (MEC), is a destructive, and locally invasive lesion in the middle ear driven by inflammation with an annual incidence of 10 per 100,000.... (Review)
Review
Middle ear cholesteatoma (MEC), is a destructive, and locally invasive lesion in the middle ear driven by inflammation with an annual incidence of 10 per 100,000. Surgical extraction/excision remains the only treatment strategy available and recurrence is high (up to 40%), therefore developing the first pharmaceutical treatments for MEC is desperately required. This review was targeted at connecting the dysregulated inflammatory network of MEC to pathogenesis and identification of pharmaceutical targets. We summarized the numerous basic research endeavors undertaken over the last 30+ years to identify the key targets in the dysregulated inflammatory pathways and judged the level of evidence for a given target if it was generated by in vitro, in vivo or clinical experiments. MEC pathogenesis was found to be connected to cytokines characteristic for Th1, Th17 and M1 cells. In addition, we found that the inflammation created damage associated molecular patterns (DAMPs), which further promoted inflammation. Similar positive feedback loops have already been described for other Th1/Th17 driven inflammatory diseases (arthritis, Crohn's disease or multiple sclerosis). A wide-ranging search for molecular targeted therapies (MTT) led to the discovery of over a hundred clinically approved drugs already applied in precision medicine. Based on exclusion criteria designed to enable fast translation as well as efficacy, we condensed the numerous MTTs down to 13 top drugs. The review should serve as groundwork for the primary goal, which is to provide potential pharmaceutical therapies to MEC patients for the first time in history. Video Abstract.
Topics: Cholesteatoma, Middle Ear; Cytokines; Ear, Middle; Humans; Inflammation
PubMed: 36123729
DOI: 10.1186/s12964-022-00953-w -
Hearing Research May 2010
Topics: Animals; Ear, Middle; Humans
PubMed: 20347945
DOI: 10.1016/j.heares.2010.03.079 -
Journal of Visualized Experiments : JoVE Jan 2024The utilization of endoscopes in modern otology has evolved from diagnostic purposes to the development of exclusive endoscopic ear surgery. This technique offers a...
The utilization of endoscopes in modern otology has evolved from diagnostic purposes to the development of exclusive endoscopic ear surgery. This technique offers a panoramic view of the middle ear and provides an optimal magnification of the oval window region, the stapes' suprastructure, and the footplate, allowing great precision in prosthesis positioning during ossiculoplasty (OPL). Various techniques for ossicular chain reconstruction have been described in the literature. Either autologous or synthetic materials can be used for reconstruction. The use of a patient's own tissue minimizes the risk of implant rejection or extrusion of the prosthesis through the tympanic membrane. On the other hand, synthetic materials like titanium are light and rigid and do not require time-consuming prosthesis remodeling. The main objective of this article is to present a comprehensive step-by-step guide that serves as a surgical manual for exclusive endoscopic OPL. This guide will explain various forms of OPL using synthetic and autologous materials. The goal is to provide a comprehensive understanding of the various surgical techniques and support the integration into clinical practice.
Topics: Humans; Ear, Middle; Ossicular Prosthesis; Incus; Stapes; Prosthesis Implantation; Treatment Outcome; Retrospective Studies
PubMed: 38345253
DOI: 10.3791/66155