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Medicina Oral, Patologia Oral Y Cirugia... Mar 2007This work seeks to alert medical and odontological staff to understanding and using interdisciplinary handling for detecting different pathologies common otic symptoms.... (Review)
Review
This work seeks to alert medical and odontological staff to understanding and using interdisciplinary handling for detecting different pathologies common otic symptoms. It offers better tools for this shared symptomatology during therapy s conservative phase. Tensor tympani muscle physiology and function in the middle ear have been veiled, even when their dysfunction and anatomical relationships may explain a group of confused otic symptoms during conventional clinical evaluation. Middle ear muscles share a common embryological and functional origin with chewing and facial muscles. This article emphasizes that these muscles share a functional neurological and anatomical dimension with the stomatognathic system; these muscles increased tonicity ceases to be a phenomenon having no logical connections. It offers functionality and importance in understanding referred otic symptoms in common with other extra-otical symptom pathologies. Tinnitus, vertigo, otic fullness sensation, hyperacusia, hypoacusia and otalgia are not only primary hearing organ symptoms. They should be redefined and related to the neighboring pathologies which can produce them. There is a need to understand temporomandibular disorders and craniofacial referred symptomatology from neurophysiologic and muscle-skeletal angles contained in the stomatognathic system. Common symptomatology is frequently observed in otic symptoms and temporomandibular disorders during daily practice; this should be understood by each discipline from a broad, anatomical and clinical perspective.
Topics: Ear Ossicles; Ear, Middle; Earache; Female; Hearing Disorders; Humans; Hyperacusis; Male; Masticatory Muscles; Muscle Contraction; Reflex; Temporomandibular Joint Disorders; Tensor Tympani; Tinnitus; Vertigo
PubMed: 17322813
DOI: No ID Found -
American Journal of Otolaryngology 1987Otosclerosis is a bone disorder of unknown etiology confined to the otic capsule. Failure of remodeling of newly formed vascular, woven bone (otospongiosis) results in... (Review)
Review
Otosclerosis is a bone disorder of unknown etiology confined to the otic capsule. Failure of remodeling of newly formed vascular, woven bone (otospongiosis) results in sclerotic bone (otosclerosis) with abnormal osteons. Involvement of the oval window causes conductive hearing loss. Electron microscopic, histochemical, and biochemical studies identify normal cellular and matrix components of otosclerotic bone without providing clues to the abnormal bone formation and resorption. Plastic-embedded, nondecalcified histologic sections with in vivo tetracycline labels permit the study of mineralization rates to separate this disorder from other bone dyscrasias that have similar histopathologic appearances. Characterization of the cells, matrix, and their mediators can yield an understanding of abnormalities that disorder bone.
Topics: Animals; Bone and Bones; Disease Models, Animal; Female; Humans; Male; Osteoclasts; Otosclerosis; Rats; Stapes; Temporal Bone
PubMed: 3324781
DOI: 10.1016/s0196-0709(87)80046-7 -
Developmental Dynamics : An Official... Dec 2020The mammalian middle ear comprises a chain of ossicles, the malleus, incus, and stapes that act as an impedance matching device during the transmission of sound from the... (Review)
Review
The mammalian middle ear comprises a chain of ossicles, the malleus, incus, and stapes that act as an impedance matching device during the transmission of sound from the tympanic membrane to the inner ear. These ossicles are derived from cranial neural crest cells that undergo endochondral ossification and subsequently differentiate into their final functional forms. Defects that occur during middle ear development can result in conductive hearing loss. In this review, we summarize studies describing the crucial roles played by signaling molecules such as sonic hedgehog, bone morphogenetic proteins, fibroblast growth factors, notch ligands, and chemokines during the differentiation of neural crest into the middle ear ossicles. In addition to these cell-extrinsic signals, we also discuss studies on the function of transcription factor genes such as Foxi3, Tbx1, Bapx1, Pou3f4, and Gsc in regulating the development and morphology of the middle ear ossicles.
Topics: Animals; Bone Morphogenetic Proteins; Cell Differentiation; Chemokines; Ear Ossicles; Ear, Middle; Fibroblast Growth Factors; Humans; Neural Crest; Signal Transduction; Transcription Factors
PubMed: 33058336
DOI: 10.1002/dvdy.260 -
Hearing Research Mar 2021As an alternative to fresh temporal bones, Thiel conserved specimens can be used in the study of ear mechanics. Conserved temporal bones do not decay, permit long-term...
BACKGROUND AND AIMS
As an alternative to fresh temporal bones, Thiel conserved specimens can be used in the study of ear mechanics. Conserved temporal bones do not decay, permit long-term experiments and overcome problems with limited access to fresh (frozen) temporal bones. Air conduction motion of the tympanic membrane (TM), stapes (ST) and round window (RW) in Thiel specimens is similar to that of fresh specimens according to reports in the literature. Our study compares this motion directly before and after conservation for the same specimens.
METHODS
The magnitude of motion of TM, ST and RW elicited by acoustic stimulation via the external auditory canal was measured using single point laser Doppler vibrometry (LDV) accessed through a posterior tympanotomy. For the initial measurements (10 ears), fresh frozen whole heads were thawed for at least 24 h. Afterwards, the entire whole heads were embalmed according to the Thiel embalming method and measurements were repeated 3 and 12 months later.
RESULTS
The magnitudes of TM, ST and RW motion before and after Thiel conservation differed maximally 10 dB on average. A significant increase in TM motion was observed at low frequencies only after long term conservation (12 months). ST motions decreased significantly between 161 and 5300 Hz after 3 months of Thiel conservation. Over the same time period RW motions decreased significantly between 100 and 161 Hz and 489-788 Hz. The ST and RW motions across all measured frequencies were lower after 3 months by 5.7 dB and 7.1 dB, respectively, without further changes after 12 months of conservation. The mean phase shift between ST and RW motion was only 2.1° for frequencies below 450 Hz.
DISCUSSION AND CONCLUSION
Thiel embalming changes motion of TM after long term conservation. ST and RW motion changed mainly after short term conservation. The phase shifts close to 180° between ST and RW motion indicates that the cochlea was still filled with liquid without air bubbles. The results show that Thiel conserved specimens can be used as an alternative model to fresh frozen preparations with some limitations when studying mechanics of the normal human ear, for example, in implant design.
Topics: Acoustic Stimulation; Embalming; Humans; Incus; Ossicular Prosthesis; Round Window, Ear; Stapes; Temporal Bone
PubMed: 33388646
DOI: 10.1016/j.heares.2020.108152 -
Audiology Research Jul 2021Soft tissue conduction is an additional mode of auditory stimulation which can be initiated either by applying an external vibrator to skin sites not overlying skull... (Review)
Review
Soft tissue conduction is an additional mode of auditory stimulation which can be initiated either by applying an external vibrator to skin sites not overlying skull bone such as the neck (so it is not bone conduction) or by intrinsic body vibrations resulting, for example, from the heartbeat and vocalization. The soft tissue vibrations thereby induced are conducted by the soft tissues to all parts of the body, including the walls of the external auditory canal. In order for soft tissue conduction to elicit hearing, the soft tissue vibrations which are induced must penetrate into the cochlea in order to excite the inner ear hair cells and auditory nerve fibers. This final stage can be achieved either by an osseous bone conduction mechanism, or, more likely, by the occlusion effect: the vibrations of the walls of the occluded canal induce air pressures in the canal which drive the tympanic membrane and middle ear ossicles and activate the inner ear, acting by means of a more air conduction-like mechanism. In fact, when the clinician applies his stethoscope to the body surface of his patient in order to detect heart sounds or pulmonary air flow, he is detecting soft tissue vibrations.
PubMed: 34287239
DOI: 10.3390/audiolres11030031 -
Acta Otorhinolaryngologica Italica :... Aug 2022Otosclerosis is an osteodystrophic disease of the otic capsule, determining conductive or mixed hearing loss, which can be successfully treated with stapedotomy. The aim...
OBJECTIVE
Otosclerosis is an osteodystrophic disease of the otic capsule, determining conductive or mixed hearing loss, which can be successfully treated with stapedotomy. The aim of the present multicentric retrospective study was to identify prognostic factors related to better auditory outcomes in stapes surgery.
METHODS
581 patients affected by otosclerosis were submitted to stapedotomy under local anaesthesia in two different hospitals. Both Teflon and titanium prostheses were adopted.
RESULTS
A statistically significant decrease of postoperative air-conduction thresholds and air-bone gap (ABG) values was seen, whereas the mean bone-conduction threshold did not differ from the preoperative condition. Among the various parameters investigated, the prosthetic material, duration of surgery and intraoperative detection of unexpected anatomical anomalies of the middle ear were found to be related to lower postoperative ABG values.
CONCLUSIONS
All the previously mentioned parameters played a significant role in determining the postoperative auditory outcomes and can therefore be considered prognostic factors for the success of the stapedotomy.
Topics: Bone Conduction; Humans; Otosclerosis; Polytetrafluoroethylene; Prognosis; Retrospective Studies; Stapes; Stapes Surgery; Titanium; Treatment Outcome
PubMed: 36254654
DOI: 10.14639/0392-100X-N0612 -
The Journal of the Acoustical Society... Nov 2022For evoked otoacoustic emissions (OAEs), the stimulus and emission signals traverse the middle ear (ME) in forward and reverse directions, respectively. In this study, a...
For evoked otoacoustic emissions (OAEs), the stimulus and emission signals traverse the middle ear (ME) in forward and reverse directions, respectively. In this study, a fully coupled three-dimensional finite-element model of the mouse ear canal (EC), ME, and cochlea was used to calculate ME pressure gains, impedances, and reflectances at the EC-entrance and stapes-footplate-cochlear-fluid interfaces. The cochlear model incorporates a series of interdigitated Y-shaped structures sandwiched between the basilar membrane and reticular lamina, each comprised of a Deiters' cell, its phalangeal-process extension, and an outer hair cell (OHC). By introducing random perturbations to the OHC gains, stimulation-frequency otoacoustic emissions (SFOAEs) were generated. Raising the perturbation magnitude from 10% to 80% increased the SFOAE magnitude by up to 24 dB in the 10-30 kHz frequency range. Increasing or decreasing the stiffness of the stapes annular ligament and eardrum by a factor of 8 changed the SFOAEs by up to 30 dB, but the round-trip ME gain as measured could not account for this. A modified round-trip ME gain, with reflections removed at the EC-entrance and stapes-cochlea boundaries, eliminated a ±10 dB discrepancy and allowed ME changes to be quantitatively associated with changes in measured OAEs.
Topics: Mice; Animals; Otoacoustic Emissions, Spontaneous; Cochlea; Ear, Middle; Stapes; Hair Cells, Auditory, Outer; Disease Models, Animal
PubMed: 36456266
DOI: 10.1121/10.0014901 -
Anatomical Record (Hoboken, N.J. : 2007) Sep 2019Incus angles of axes (the angle between "short process axis" and the "long process axis") are more open in humans than chimpanzees: 64.0 versus 55.7 degrees (Quam et...
Incus angles of axes (the angle between "short process axis" and the "long process axis") are more open in humans than chimpanzees: 64.0 versus 55.7 degrees (Quam et al.: J Anat 225 (2014) 167-196). However, Flohr et al. (Anat Rec 293 (2010) 2094-2106) raise concern about interobserver agreement of the axes. The concern is important as phylogenetic relationships of mammals are inferred from the incus (and malleus and stapes). We sought to check (1) interobserver agreement; and (2) if the angles of the axes of incudes (incuses) exhibit bilateral symmetry, which is expected if the axes are genetically determined. We studied incudes from 41 modern adult crania with clinically normal temporal bones. Angles of axes were determined on rectilinear digital photographs of incudes in standard lateral orientation. Two observers independently drew the axes and measured the axes. Interobserver agreement was within 4 degrees for 24 of 34 left-sided incudes and for 27 of 35 right-sided incudes. The mean of the two observers' angle determinations were used. Left incudes' median was 67 degrees, range 60-73; right 67.5 degrees, range 58-77. Bilateral symmetry of angles of axes was found: r = 0.55, N = 31, 95% CI 0.24-0.75. Angles of axes of modern human incudes are probably genetically determined features, but are of doubtful physiologic or evolutionary advantage in modern humans. Interobserver agreement of angles of modern human axes is concerning and must be specified in reports. Consideration should be given to a convention to designate axes in ambiguous cases. Anat Rec, 302:1615-1619, 2019. © 2019 American Association for Anatomy.
Topics: Adult; Humans; Incus; Mastoid; Observer Variation; Temporal Bone
PubMed: 31120197
DOI: 10.1002/ar.24178 -
PloS One 2021As the resolution of 3D printing techniques improves, the possibility of individualized, 3-ossicle constructions adds a new dimension to middle ear prostheses. In order...
As the resolution of 3D printing techniques improves, the possibility of individualized, 3-ossicle constructions adds a new dimension to middle ear prostheses. In order to optimize these designs, it is essential to understand how the ossicles and ligaments work together to transmit sound, and thus how ligaments should be replicated in a middle ear reconstruction. The middle ear ligaments are thought to play a significant role in maintaining the position of the ossicles and constraining axis of rotation. Paradoxically, investigations of the role of ligaments to date have shown very little impact on middle ear sound transmission. We explored the role of the two attachments in the gerbil middle ear analogous to human ligaments, the posterior incudal ligament and the anterior mallear process, severing both attachments and measuring change in hearing sensitivity. The impact of severing the attachments on the position of the ossicular chain was visualized using synchrotron microtomography imaging of the middle ear. In contrast to previous studies, a threshold change on the order of 20 dB across a wide range of frequencies was found when both ligaments were severed. Concomitantly, a shift in position of the ossicles was observed from the x-ray imaging and 3D renderings of the ossicular chain. These findings contrast with previous studies, demonstrating that these ligaments play a significant role in the transmission of sound through the middle ear. It appears that both mallear and incudal ligaments must be severed in order to impair sound transmission. The results of this study have significance for middle ear reconstructive surgery and the design of 3D-printed three-ossicle biocompatible prostheses.
Topics: Acoustic Stimulation; Action Potentials; Animals; Auditory Threshold; Biocompatible Materials; Cochlea; Ear, Middle; Female; Gerbillinae; Lasers, Gas; Ligaments; Male; Ossicular Prosthesis; Printing, Three-Dimensional; X-Ray Microtomography
PubMed: 34428235
DOI: 10.1371/journal.pone.0255821 -
Journal of Anatomy Aug 2022The vascular supply of the human auditory ossicles has long been of anatomical and clinical interest. While the external blood supply has been well-described, there is...
The vascular supply of the human auditory ossicles has long been of anatomical and clinical interest. While the external blood supply has been well-described, there is only limited information available regarding the internal vascular architecture of the ossicles, and there has been little comparison of this between individuals. Based on high-resolution micro-CT scans, we made reconstructions of the internal vascular channels and cavities in 12 sets of ossicles from elderly donors. Despite considerable individual variation, a common basic pattern was identified. The presence of channels within the stapes footplate was confirmed. The long process of the incus and neck of the stapes showed signs of bony erosion in all specimens examined. More severe erosion was associated with interruption of some or all of the main internal vascular channels which normally pass down the incudal long process; internal excavation of the proximal process could interrupt vascular channels in ossicles which did not appear to be badly damaged from exterior inspection. An awareness of this possibility may be helpful for surgical procedures that compromise the mucosal blood supply. We also calculated ossicular densities, finding that the malleus tends to be denser than the incus. This is mainly due to a lower proportion of vascular channels and cavities within the malleus.
Topics: Aged; Ear Ossicles; Ear, Middle; Humans; Incus; Malleus; Tomography, X-Ray Computed
PubMed: 35357009
DOI: 10.1111/joa.13661