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Combined high-speed holographic shape and full-field displacement measurements of tympanic membrane.Journal of Biomedical Optics Sep 2018The conical shape of the tympanic membrane (TM or eardrum) plays an important role in its function, such that variations in shape alter the acoustically induced motions...
The conical shape of the tympanic membrane (TM or eardrum) plays an important role in its function, such that variations in shape alter the acoustically induced motions of the TM. We present a method that precisely determines both shape and acoustically induced transient response of the entire TM using the same optics and maintaining the same coordinate system, where the TM transient displacements due to a broadband acoustic click excitation (50-μs impulse) and the shape are consecutively measured within <200 ms. Interferograms gathered with continuous high-speed (>2 kHz) optical phase sampling during a single 100-ms wavelength tuning ramp allow precise and rapid reconstructions of the TM shape at varied resolutions (50 to 200 μm). This rapid acquisition of full-field displacements and shape is immune to slow disturbances introduced by breathing or heartbeat of live subjects. Knowledge of TM shape and displacements enables the estimation of surface normal displacements regardless of the orientation of the TM within the measurement system. The proposed method helps better define TM mechanics and provides TM structure and function information useful for the diagnosis of ear disease.
Topics: Acoustic Stimulation; Holography; Humans; Interferometry; Tympanic Membrane; Vibration
PubMed: 30255670
DOI: 10.1117/1.JBO.24.3.031008 -
PloS One 2021Chronic infections are often connected to biofilm formation. In presence of implants, this can lead to loss of the implant. Systemic or local application of drugs is...
Chronic infections are often connected to biofilm formation. In presence of implants, this can lead to loss of the implant. Systemic or local application of drugs is relatively ineffective in case of biofilm formation. One technique to provide antibacterial properties on demand is the antibacterial photodynamic therapy (aPDT). Using this technique, these properties can be "switched on" by light illumination. In the middle ear with the semitransparent tympanic membrane, it might be possible in future to activate the antibacterial effect without opening the membrane. Therefore, we investigated the optical absorbance spectra of the tympanic membrane. Optical absorbance spectra were measured in ex vivo preparations from neonatal and adult rats with the membrane still being attached to the surrounding bony ring and four human samples. After performing area scans, the spot with the lowest absorbance being surrounded by a ring like structure with higher absorbance was chosen as region of interest for scanning wavelengths between 300 and 900 nm. Absorbance is generally higher at lower wavelengths with a local absorbance maximum at 420 nm and a weak second maximum with two neighbouring peaks at 540 / 580 nm and is significantly higher in adult rats compared to neonatal rats where about 10% of light was transmitted. The human samples show similar characteristics with a little higher absorbance. For activation of aPDT through the tympanic membrane, larger wavelengths are more promising. Whether the amount of light transmitted through the membrane would be sufficient to induce aPDT remains to be tested in further experiments.
Topics: Animals; Bacterial Physiological Phenomena; Biofilms; Humans; Light; Photochemotherapy; Photosensitizing Agents; Rats; Rats, Sprague-Dawley; Species Specificity; Tympanic Membrane
PubMed: 34293032
DOI: 10.1371/journal.pone.0254902 -
Biological Cybernetics Oct 2016ICE stands for internally coupled ears. More than half of the terrestrial vertebrates, such as frogs, lizards, and birds, as well as many insects, are equipped with ICE...
ICE stands for internally coupled ears. More than half of the terrestrial vertebrates, such as frogs, lizards, and birds, as well as many insects, are equipped with ICE that utilize an air-filled cavity connecting the two eardrums. Its effect is pronounced and twofold. On the basis of a solid experimental and mathematical foundation, it is known that there is a low-frequency regime where the internal time difference (iTD) as perceived by the animal may well be 2-5 times higher than the external ITD, the interaural time difference, and that there is a frequency plateau over which the fraction iTD/ITD is constant. There is also a high-frequency regime where the internal level (amplitude) difference iLD as perceived by the animal is much higher than the interaural level difference ILD measured externally between the two ears. The fundamental tympanic frequency segregates the two regimes. The present special issue devoted to "internally coupled ears" provides an overview of many aspects of ICE, be they acoustic, anatomical, auditory, mathematical, or neurobiological. A focus is on the hotly debated topic of what aspects of ICE animals actually exploit neuronally to localize a sound source.
Topics: Acoustics; Animals; Ear; Hearing; Sound Localization; Tympanic Membrane
PubMed: 27838890
DOI: 10.1007/s00422-016-0702-x -
Cell Stem Cell Feb 2021The tympanic membrane (TM) is critical for hearing and requires continuous clearing of cellular debris, but little is known about homeostatic mechanisms in the TM...
The tympanic membrane (TM) is critical for hearing and requires continuous clearing of cellular debris, but little is known about homeostatic mechanisms in the TM epidermis. Using single-cell RNA sequencing, lineage tracing, whole-organ explant, and live-cell imaging, we show that homeostatic TM epidermis is distinct from other epidermal sites and has discrete proliferative zones with a three-dimensional hierarchy of multiple keratinocyte populations. TM stem cells reside in a discrete location of the superior TM and generate long-lived clones and committed progenitors (CPs). CP clones exhibit lateral migration, and their proliferative capacity is supported by Pdgfra+ fibroblasts, generating migratory but non-proliferative progeny. Single-cell sequencing of the human TM revealed similar cell types and transcriptional programming. Thus, during homeostasis, TM keratinocytes transit through a proliferative CP state and exhibit directional lateral migration. This work forms a foundation for understanding TM disorders and modeling keratinocyte biology.
Topics: Epidermal Cells; Epidermis; Humans; Keratinocytes; Stem Cells; Tympanic Membrane
PubMed: 33181078
DOI: 10.1016/j.stem.2020.10.006 -
Brazilian Journal of Otorhinolaryngology 2022Traumatic large tympanic membrane perforations usually fail to heal and require longer healing times. Few studies have compared the healing and hearing outcomes between... (Randomized Controlled Trial)
Randomized Controlled Trial
INTRODUCTION
Traumatic large tympanic membrane perforations usually fail to heal and require longer healing times. Few studies have compared the healing and hearing outcomes between gelatin sponge patching and ofloxacin otic solution.
OBJECTIVES
To compare the healing outcomes of large traumatic tympanic membrane perforations treated with gelatin sponge, ofloxacin otic solution, and spontaneous healing.
METHODS
Traumatic tympanic membrane perforations >50% of the entire eardrum were randomly divided into three groups: ofloxacin otic solution, gelatin sponge patch and spontaneous healing groups. The healing outcome and hearing gain were compared between the three groups at 6 months.
RESULTS
A total of 136 patients with large traumatic tympanic membrane perforations were included in analyses. The closure rates were 97.6% (40/41), 87.2% (41/47), and 79.2% (38/48) in the ofloxacin otic solution, gelatin sponge patch, and spontaneous healing groups, respectively (p=0.041). The mean times to closure were 13.12±4.61, 16.47±6.24, and 49.51±18.22 days in these groups, respectively (p<0.001).
CONCLUSIONS
Gelatin sponge patch and ofloxacin otic solution may serve as effective and inexpensive treatment strategies for traumatic large tympanic membrane perforations. However, ofloxacin otic solution must be self-applied daily to keep the perforation edge moist, while gelatin sponge patching requires periodic removal and re-patching.
Topics: Gelatin; Humans; Ofloxacin; Tympanic Membrane; Tympanic Membrane Perforation; Wound Healing
PubMed: 32456874
DOI: 10.1016/j.bjorl.2020.03.007 -
Genesis (New York, N.Y. : 2000) Mar 2020The ear drum, or tympanic membrane (TM), is a key component in the intricate relay that transmits air-borne sound to our fluid-filled inner ear. Despite early belief... (Review)
Review
The ear drum, or tympanic membrane (TM), is a key component in the intricate relay that transmits air-borne sound to our fluid-filled inner ear. Despite early belief that the mammalian ear drum evolved as a transformation of a reptilian drum, newer fossil data suggests a parallel and independent evolution of this structure in mammals. The term "drum" belies what is in fact a complex three-dimensional structure formed from multiple embryonic cell lineages. Intriguingly, disease affects the ear drum differently in its different parts, with the superior and posterior parts being much more frequently affected. This suggests a key role for the developmental details of TM formation in its final form and function, both in homeostasis and regeneration. Here we review recent studies in rodent models and humans that are beginning to address large knowledge gaps in TM cell dynamics from a developmental biologist's point of view. We outline the biological and clinical uncertainties that remain, with a view to guiding the indispensable contribution that developmental biology will be able to make to better understanding the TM.
Topics: Animals; Disease Susceptibility; Ear, Middle; Humans; Mammals; Organogenesis; Tympanic Membrane; Vertebrates
PubMed: 31763764
DOI: 10.1002/dvg.23348 -
Medicina (Kaunas, Lithuania) Apr 2021Several theories describe the development of the retraction pocket of the tympanic membrane (RP). Many authors suggest that the negative middle ear pressure is the main... (Review)
Review
Several theories describe the development of the retraction pocket of the tympanic membrane (RP). Many authors suggest that the negative middle ear pressure is the main reason responsible for developing this condition. A narrative review has been undertaken, and conclusions are drawn reflecting a current knowledge with our new observations in the histological and immunohistochemical study. Recent studies show the important role of inflammation in the development and progression of RP. A review of the available literature shows that the inflammation plays a key role in pathogenesis of the RP and its progression to the cholesteatoma. We support this statement with our new results from histological and immunohistochemical analysis of the RPs.
Topics: Cholesteatoma, Middle Ear; Humans; Inflammation; Tympanic Membrane
PubMed: 33924803
DOI: 10.3390/medicina57050425 -
European Archives of... Feb 2022Tympanic membrane retraction (TMR) is a relatively common otological finding. However, no consensus on its management exists. We are looking especially for a treatment...
IMPORTANCE
Tympanic membrane retraction (TMR) is a relatively common otological finding. However, no consensus on its management exists. We are looking especially for a treatment strategy in the military population who are unable to attend frequent follow-up visits, and who experience relatively more barotrauma at great heights and depths and easily suffer from otitis externa from less hygienic circumstances.
OBJECTIVE
To assess and summarize the available evidence for the effectiveness of surgical interventions and watchful waiting policy in patients with a tympanic membrane retraction.
EVIDENCE REVIEW
The protocol for this systematic review was published at Prospero (207859). PubMed, Embase, and the Cochrane Database of Systematic Reviews were systematically searched from inception up to September 2020 for published and unpublished studies. We included randomized trials and observational studies that investigated surgical interventions (tympanoplasty, ventilation tube insertion) and wait-and-see policy. The primary outcomes of this study were clinical remission of the tympanic membrane retraction, tympanic membrane perforations and cholesteatoma development.
FINDINGS
In total, 27 studies were included, consisting of 1566 patients with TMRs. We included data from 2 randomized controlled trials (76 patients) and 25 observational studies (1490 patients). Seven studies (329 patients) investigated excision of the TMR with and without ventilation tube placement, 3 studies (207 patients) investigated the wait-and-see policy and 17 studies (1030 patients) investigated tympanoplasty for the treatment of TMRs.
CONCLUSIONS AND RELEVANCE
This study provides all the studies that have been published on the surgical management and wait-and-policy for tympanic membrane retractions. No high level of evidence comparative studies has been performed. The evidence for the management of tympanic membrane retractions is heterogenous and depends on many factors such as the patient population, location and severity of the TMR and presence of other ear pathologies (e.g., perforation, risk of cholesteatoma and serous otitis media).
Topics: Humans; Middle Ear Ventilation; Otitis Media with Effusion; Tympanic Membrane; Tympanoplasty
PubMed: 33689022
DOI: 10.1007/s00405-021-06719-3 -
Molecules (Basel, Switzerland) May 2022Tympanic membrane perforation (TMP), a common disease, often needs a scaffold as the patch to support surgery. Due to the environment of auditory meatus, the patch can...
Tympanic membrane perforation (TMP), a common disease, often needs a scaffold as the patch to support surgery. Due to the environment of auditory meatus, the patch can be infected by bacteria that results in failure; therefore, the ideal scaffold may combine biomimetic and antibacterial features. In this work, gelatin was used as the electrospinning framework, genipin as the crosslinking agent, and levofloxacin as an antibacterial in order to prepare the scaffold for TMP. Different contents of levofloxacin have been added to gelatin/genipin. It was found that, with the addition of levofloxacin, the gelatin/genipin membranes exhibit improved hydrophilia and enhanced tensile strength. The antibacterial and cell-cultured experiments showed that the prepared antibacterial membranes had excellent antibacterial properties and good biocompatibility, respectively. In summary, levofloxacin is a good group for the gelatin/genipin scaffold because it improves the physical properties and antibacterial action. Compared with different amounts of levofloxacin, a gelatin/genipin membrane with 1% levofloxacin is more suitable for a TM.
Topics: Anti-Bacterial Agents; Gelatin; Iridoids; Levofloxacin; Nanofibers; Tissue Scaffolds; Tympanic Membrane
PubMed: 35566258
DOI: 10.3390/molecules27092906 -
The Journal of Laryngology and Otology Feb 2022For centuries, the tympanum has remained the only visible structure of the organ of hearing. This study aimed to trace the understanding of the tympanic membrane from... (Review)
Review
OBJECTIVE
For centuries, the tympanum has remained the only visible structure of the organ of hearing. This study aimed to trace the understanding of the tympanic membrane from antiquity to the early twentieth century.
METHODS
A review was conducted of primary and secondary historical and scientific literature describing the tympanic membrane anatomy.
RESULTS
Although ancient polymaths sensed that sounds were vibrations that could spread in the air and be perceived by the hearing organ, there were numerous misconceptions about the tympanum until human dissections performed during the Renaissance. The tympanum was correctly described only centuries later when technological advances enabled otologists to understand it as a fundamental part of the hearing organ.
CONCLUSION
The tympanic membrane history reflects key stages in medical knowledge; limited for centuries, a great technological leap was possible in the nineteenth century, contributing to the emergence of otologists and laying the foundations of modern otology.
Topics: History, 16th Century; History, 17th Century; History, 18th Century; History, 19th Century; History, Ancient; History, Medieval; Humans; Otolaryngology; Tympanic Membrane
PubMed: 34819180
DOI: 10.1017/S0022215121003844