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Journal of Morphology Aug 2019The evolution of the various hearing adaptations is connected to major structural changes in nearly all groups of vertebrates. Besides hearing, the detection of... (Review)
Review
The evolution of the various hearing adaptations is connected to major structural changes in nearly all groups of vertebrates. Besides hearing, the detection of acceleration and orientation in space are key functions of this mechanosensory system. The symposium "show me your ear - the inner and middle ear in vertebrates" held at the 11th International Congress of Vertebrate Morphology (ICVM) 2016 in Washington, DC (USA) intended to present current research addressing adaptation and evolution of the vertebrate otic region, auditory ossicles, vestibular system, and hearing physiology. The symposium aimed at an audience with interest in hearing research focusing on morphological, functional, and comparative studies. The presented talks and posters lead to the contributions of this virtual issue highlighting recent advances in the vertebrate balance and hearing system. This article serves as an introduction to the virtual issue contributions and intends to give a short overview of research papers focusing on vertebrate labyrinth and middle ear related structures in past and recent years.
Topics: Animals; Ear, Inner; Ear, Middle; Hearing; Vertebrates
PubMed: 30117612
DOI: 10.1002/jmor.20880 -
Journal of Anatomy Feb 2016The mammalian ear is a complex structure divided into three main parts: the outer; middle; and inner ear. These parts are formed from all three germ layers and neural... (Review)
Review
The mammalian ear is a complex structure divided into three main parts: the outer; middle; and inner ear. These parts are formed from all three germ layers and neural crest cells, which have to integrate successfully in order to form a fully functioning organ of hearing. Any defect in development of the outer and middle ear leads to conductive hearing loss, while defects in the inner ear can lead to sensorineural hearing loss. This review focuses on the development of the parts of the ear involved with sound transduction into the inner ear, and the parts largely ignored in the world of hearing research: the outer and middle ear. The published data on the embryonic origin, signalling, genetic control, development and timing of the mammalian middle and outer ear are reviewed here along with new data showing the Eustachian tube cartilage is of dual embryonic origin. The embryonic origin of some of these structures has only recently been uncovered (Science, 339, 2013, 1453; Development, 140, 2013, 4386), while the molecular mechanisms controlling the growth, structure and integration of many outer and middle ear components are hardly known. The genetic analysis of outer and middle ear development is rather limited, with a small number of genes often affecting either more than one part of the ear or having only very small effects on development. This review therefore highlights the necessity for further research into the development of outer and middle ear structures, which will be important for the understanding and treatment of conductive hearing loss.
Topics: Animals; Ear, External; Ear, Middle; Hearing; Mammals
PubMed: 26227955
DOI: 10.1111/joa.12344 -
Philosophical Transactions of the Royal... Jul 2023Modularity (segmentation), homology and heterochrony were essential concepts embraced by Gavin de Beer in his studies of the development and evolution of the vertebrate... (Review)
Review
Modularity (segmentation), homology and heterochrony were essential concepts embraced by Gavin de Beer in his studies of the development and evolution of the vertebrate skull. While his pioneering contributions have stood the test of time, our understanding of the biological processes that underlie each concept has evolved. We assess de Beer's initial training as an experimental embryologist; his switch to comparative and descriptive studies of skulls, jaws and middle ear ossicles; and his later research on the mammalian skull, including his approach to head segmentation. The role of cells of neural crest and mesodermal origin in skull development, and developmental, palaeontological and molecular evidence for the origin of middle ear ossicles in the evolutionary transition from reptiles to mammals are used to illustrate our current understanding of modularity, homology and heterochrony. This article is part of the theme issue 'The mammalian skull: development, structure and function'.
Topics: Animals; Beer; Biological Evolution; Skull; Head; Mammals
PubMed: 37183898
DOI: 10.1098/rstb.2022.0078 -
Journal of Anatomy Feb 2016The anterior fixation of the anterior process of the malleus has been studied in a number of Cetartiodactyla. This anterior process, also known as processus gracilis, is... (Review)
Review
The anterior fixation of the anterior process of the malleus has been studied in a number of Cetartiodactyla. This anterior process, also known as processus gracilis, is provided by the prearticular (gonial), a dermal bone, whereas the cartilage of Meckel becomes resorbed in perinatal ontogenetic stages. Posteriorly, the prearticular fuses with the cartilaginous caput of the malleus; rostrally, the prearticular (= processus gracilis) is always fixed to the anterior crus of the ectotympanic by an extremely thin splint (thickness < 50 μm). From the rostral part of the processus gracilis all studied cetartiodactyls develop a processus internus of considerable size. This process was known as 'ossiculum accessorium mallei' in former times, and its homology has been disputed; from our microscopic-anatomical study we can definitely state that it is always a 'processus internus praearticularis'. This process contacts the fascia of the tensor tympani muscle. In non-ruminants, it articulates dorsally with the tegmen tympani and dorsolaterally with the ectotympanic; whereas the processus gracilis becomes more and more slender, the processus internus may grow to considerable size and normally is fused to the adjacent bones already in juveniles. However, in ruminants, the tegmen tympani tends to disappear and the processus internus praearticularis appears as relatively small bony knob at the floor of the medial cranial cavity, and it seems not to be fused to the surrounding bones; in later age stages, it may become secondarily overgrown by the petrosal. This dorsally exposed processus internus praearticularis seems to be a synapomorphy of the Ruminantia. The functional meaning of this internal process of the prearticular, which is also developed to a minor degree in Carnivora, remains unclear at the moment - but we present some speculations about this.
Topics: Animals; Malleus; Mammals; Ruminants; Swine
PubMed: 26510377
DOI: 10.1111/joa.12393 -
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 -
Otology & Neurotology : Official... Jul 2017To evaluate the outcome and per- and postoperative complications of the surgical management of patients with a persistent stapedial artery (PSA). (Review)
Review
OBJECTIVE
To evaluate the outcome and per- and postoperative complications of the surgical management of patients with a persistent stapedial artery (PSA).
METHODS
A systemic literature search for reports on patients treated for pulsatile tinnitus and/or conductive hearing loss caused by a PSA was conducted of the PubMed and Embase databases using the terms "stapedial" and "artery." Inclusion criteria were adequate description of the intervention and pre- and postoperative signs and symptoms. In addition, one case of a PSA, treated at VU University Medical Center Amsterdam, The Netherlands, was included in this series.
INTERVENTION
Middle ear surgery consisting of stapedotomy or stapedectomy, and/or transection of the PSA.
MAIN OUTCOME MEASURES
Pre- and postoperative hearing levels, pre- and postoperative pulsatile tinnitus, and per- and postoperative complications.
RESULTS
Seventeen patients and 18 operated ears were evaluated (16 patients described in 14 articles and our case). Twelve out of 14 ears in which a stapedotomy or stapedectomy was initiated experienced improvement in hearing. In four cases pulsatile tinnitus was described pre- and postoperatively. In all four, pulsatile tinnitus subsided after transection of the PSA. Peroperative bleeding from the PSA was described in four patients, which could be controlled during the procedure. No significant postoperative sequelae were reported.
CONCLUSIONS
In case of a PSA, improvement of conductive hearing loss is best achieved by stapes surgery, while pulsatile tinnitus is effectively treated with transection of the PSA. To date no long-term postoperative complications have been reported.
Topics: Adult; Arteries; Female; Hearing Loss, Conductive; Humans; Male; Middle Aged; Netherlands; Postoperative Complications; Stapes; Stapes Surgery; Tinnitus
PubMed: 28590999
DOI: 10.1097/MAO.0000000000001466 -
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 -
BMC Medical Imaging May 2024Precision and intelligence in evaluating the complexities of middle ear structures are required to diagnose auriculotemporal and ossicle-related diseases within...
Precision and intelligence in evaluating the complexities of middle ear structures are required to diagnose auriculotemporal and ossicle-related diseases within otolaryngology. Due to the complexity of the anatomical details and the varied etiologies of illnesses such as trauma, chronic otitis media, and congenital anomalies, traditional diagnostic procedures may not yield accurate diagnoses. This research intends to enhance the diagnosis of diseases of the auriculotemporal region and ossicles by combining High-Resolution Spiral Computed Tomography (HRSCT) scanning with Deep Learning Techniques (DLT). This study employs a deep learning method, Convolutional Neural Network-UNet (CNN-UNet), to extract sub-pixel information from medical photos. This method equips doctors and researchers with cutting-edge resources, leading to groundbreaking discoveries and better patient healthcare. The research effort is the interaction between the CNN-UNet model and high-resolution Computed Tomography (CT) scans, automating activities including ossicle segmentation, fracture detection, and disruption cause classification, accelerating the diagnostic process and increasing clinical decision-making. The suggested HRSCT-DLT model represents the integration of high-resolution spiral CT scans with the CNN-UNet model, which has been fine-tuned to address the nuances of auriculotemporal and ossicular diseases. This novel combination improves diagnostic efficiency and our overall understanding of these intricate diseases. The results of this study highlight the promise of combining high-resolution CT scanning with the CNN-UNet model in otolaryngology, paving the way for more accurate diagnosis and more individualized treatment plans for patients experiencing auriculotemporal and ossicle-related disruptions.
Topics: Humans; Tomography, Spiral Computed; Ear Ossicles; Deep Learning; Ear Diseases; Temporal Bone; Adult; Neural Networks, Computer
PubMed: 38724896
DOI: 10.1186/s12880-024-01277-6 -
The Journal of International Advanced... Apr 2020Air-bone gaps (ABGs) are commonly found in patients with conductive or mixed hearing loss generally due to outer- and/or middle-ear diseases such as otitis externa,... (Review)
Review
Air-bone gaps (ABGs) are commonly found in patients with conductive or mixed hearing loss generally due to outer- and/or middle-ear diseases such as otitis externa, tympanic membrane perforation, interruption or fixation of the ossicular chain, and chronic suppurative otitis media. ABGs can also be found in correlation with inner-ear disorders, such as endolymphatic hydrops, enlarged vestibular aqueduct syndrome, semicircular canal dehiscence, gusher syndrome, cochlear dehiscence, and Paget disease's as well cerebral vascular anomalies including dural arteriovenous fistula. The typical clinical presentation of inner-ear conditions or cerebral vascular anomalies causing ABGs includes audiological and vestibular symptoms like vertigo, oscillopsia, dizziness, imbalance, spinning sensation, pulsatile or continuous tinnitus, hyperacusis, autophony, auricular fullness, Tullio's phenomenon, and Hennebert's sign. Establishing a definitive diagnosis of the underlying condition in patients presenting with an ABG is often challenging to do and, in many patients, the condition may remain undefined. Results from an accurate clinical, audiological, and vestibular evaluation can be suggestive for the underlying condition; however, radiological assessment by computed tomography and/or magnetic resonance imaging is mandatory to confirm any diagnostic suspicion. In this review, we describe and discuss the most recent updates available regarding the clinical presentation and diagnostic workup of inner-ear conditions that may present together with ABGs.
Topics: Air; Bone Conduction; Bone and Bones; Central Nervous System Vascular Malformations; Child; Cochlea; Ear Ossicles; Endolymphatic Hydrops; Female; Hearing Loss; Hearing Loss, Conductive; Hearing Loss, Mixed Conductive-Sensorineural; Hearing Loss, Sensorineural; Humans; Labyrinth Diseases; Magnetic Resonance Imaging; Male; Meniere Disease; Middle Aged; Osteitis Deformans; Semicircular Canal Dehiscence; Tomography, X-Ray Computed; Vestibular Aqueduct
PubMed: 32401207
DOI: 10.5152/iao.2020.7764