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Optical coherence tomography (OCT) is a novel technology for performing real-time high-speed and high-resolution cross-sectional imaging on the micro-scale in situ. It is analogous to ultrasound imaging, except that it uses light instead of sound. OCT has recently been introduced in auditory research to visualize the various structures of the ear with a minimally invasive operation. In addition, OCT can be used as a vibrometry system that is capable to detect sound-induced sub-nanometer vibrations of the middle and inner ear. OCT-vibrometry measures depth-resolved vibrations into the specimen, which overcomes several limitations of classical vibrometry techniques (e.g., single surface point measurements using laser interferometry). In this article, we illustrate how to visualize the anatomy and function of the middle and inner ear (the cochlea) in a gerbil model using recently developed spectral-domain OCT. Our results demonstrate that the largest clinical impact of OCT for otology is to visualize various pathologies and quantify sound conduction and processing in the individual peripheral human ear. [ABSTRACT FROM AUTHOR]

Background: Acellular dermal allograft (AlloDerm) and cartilage perichondrium are two common materials used for repair of tympanic membrane perforations (TMPs). To date, comparative evaluations of their efficacy have rarely been reported. Aim/objectives: To compare anatomical and audiological outcomes between AlloDerm and cartilage perichondrium in type I tympanoplasty. Methods: A total of 61 patients of TMP were studied. In total, 27 patients (Group 1) underwent AlloDerm myringoplasty, and the remaining 34 patients (Group 2) underwent perichondrium myringoplasty. Operating time, closure rate and hearing gain were compared between Groups 1 and 2. Results: Successful closure rates at 6-month follow-up were 88.9% (Group 1) and 82.4% (group 2). The average improvement of air-bone gap (ABG) was 13.5 ± 11.8 dB for Group 1 and 13.1 ± 13.1 dB for Group 2. The difference in between preoperative and 6 months postoperative ABG values was statistically significant (p <.001). Conclusions and significance: Success rates and improvement of hearing level were similar for the AlloDerm (Group 1) and the cartilage perichondrium (Group 2) groups. However, AlloDerm requires shorter operative time and avoids the incisions in the harvest of allografts. Our results suggest that AlloDerm can be recommended as an attractive alternative to cartilage grafts. [ABSTRACT FROM AUTHOR]

Round window membrane (RWM) application of ouabain is known to selectively destroy type I spiral ganglion cells (SGCs) in cochleas of several rodent species, while leaving hair cells intact. This protocol has been used in rats and Mongolian gerbils, but observations in the guinea pig are conflicting. This is why we reinvestigated the effect of ouabain on the guinea pig cochlea. Ouabain solutions of different concentrations were placed, in a piece of gelfoam, upon the RWM of the right cochleas. Auditory function was assessed using acoustically evoked auditory brainstem responses (aABR). Finally, cochleas were fixed and processed for histological examination. Due to variability within treatment groups, histological data was pooled and three categories based upon general histological observations were defined: cochleas without outer hair cell (OHC) and SGC loss (Category 1), cochleas with OHC loss only (Category 2), and cochleas with OHC and SGC loss (Category 3). Animals treated with 1 mM or 10 mM ouabain showed shifts in hearing thresholds, corresponding with varying histological changes in their cochleas. Most cochleas exhibited complete outer hair cell loss in the basal and middle turns, while some had no changes, together with either moderate or near-complete loss of SGCs. Neither loss of inner hair cells nor histological changes of the stria vascularis were observed in any of the animals. Cochleas in Category 1 had normal aABRs and morphology. On average, in Category 2 OHC loss was 46.0±5.7%, SGC loss was below threshold, ABR threshold shift was 44.9±2.7 dB, and ABR wave II amplitude was decreased by 17.1±3.8 dB. In Category 3 OHC loss was 68.3±6.9%, SGC loss was 49.4±4.3%, ABR threshold shift was 39.0±2.4 dB, and ABR amplitude was decreased by 15.8±1.6 dB. Our results show that ouabain does not solely destroy type I SGCs in the guinea pig cochlea. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study is to compare hearing improvements in the air-bone gap (ABG) after type III tympanoplasties, comparing between incus transposition (IT) and partial ossicular replacement prosthesis (PORP). Materials and methods: Publications in English were searched in PUBMED database and were systematically reviewed. A total of 14 articles were included, obtaining 1055 patients, 614 for the IT group and 441 for the PORP group. Preoperative ABG, postoperative ABG, dB gain and ABG closure rate were compared. Results: IT group: preoperative ABG of 31.74 dB (SD 10.51); postoperative ABG of 18.97 dB (SD 10.6); dB gain of 12.76 dB (SD 14.97); and ABG closure rate of 64.48%. PORP group: preoperative ABG of 28.02 dB (SD 10.47); postoperative ABG of 16.27 dB (SD 10.45); dB gain of 11.75 (SD 15.02); and ABG closure rate of 71.32%. No significant statistical difference was found in dB mean gain between groups (p > .05), although a difference was found in the ABG closure rate between groups favouring PORP series (p < .05). Conclusion: An improvement in hearing results was observed within both groups after type III tympanoplasty. There is no difference in decibels gained between both ossiculoplasty materials, but a better closure rate (%) was observed in the PORP group. [ABSTRACT FROM AUTHOR]

BACKGROUND: Actual noise reduction of the earmuffs is considered as one of the main challenges for the evaluation of the effectiveness of a hearing conservation program. OBJECTIVE: The current study aimed to determine the real world noise attenuation of current hearing protection devices in typical workplaces using a field microphone in real ear (FMIRE) method. METHODS: In this cross-sectional study, five common earmuffs were investigated among 50 workers in two industrial factories with different noise characteristics. Noise reduction data was measured with the use of earmuffs based on the ISO 11904 standard, field microphone in real ear method, using noise dosimeter (SVANTEK, model SV 102) equipped with a microphone SV 25 model. RESULTS: The actual insertion losses (IL) of the tested earmuffs in octave band were lower than the labeled insertion loss data (p < 0.05). The frequency nature of noise to which workers are exposed has noticeable effects on the actual noise reduction of earmuffs (p < 0.05). The results suggest that the proportion of time using earmuffs has a considerable impact on the effective noise reduction during the workday. CONCLUSIONS: Data about the ambient noise characteristics is a key criterion when evaluating the acoustic performance of hearing protectors in any workplaces. Comfort aspects should be considered as one of the most important criteria for long-term use and effective wearing of hearing protection devices. FMIRE could facilitate rapid and simple measurement of the actual performance of the current earmuffs employed by workers during different work activities. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the canal wall up (CWU) technique combined with mastoid obliteration used in cholesteatoma surgery from the aspects of safety and function. Study design: Retrospective chart review. Information was extracted from a medical database and complementary data from patient files and audiograms were collected and recorded retrospectively. Setting: A tertiary-stage hospital and a secondary-stage hospital. Surgeons of various levels of experience. Method: Data from a consecutive group of 230 primary operations for cholesteatoma surgery using CWU with obliteration employing the combined approach tympanoplasty (CAT) technique, from January 1994 to December 2009 were analyzed. Results: In 90% of the ears, the anatomy was normalized with an intact ear drum. The frequency of residual cholesteatoma was 1% and the frequency of recurrent cholesteatoma 8%. Hearing was improved one year postoperatively and remained improved three years postoperatively. No patient suffered a total hearing loss. Conclusions: CWU procedure comprising CAT with obliteration of the mastoid is a safe surgical method with a low frequency of residual and recurrent disease and a good hearing preservation. [ABSTRACT FROM AUTHOR]

Objectives: The goal of this study was to evaluate the effects of middle ear packing agents (MEPA) on post-operative hearing improvement and complications after tympanoplasty in patients with adhesive otitis media (OM). Materials and methods: Patients with adhesive OM who underwent tympanoplasty surgery were enrolled in the study between January 2012 and January 2015. A total of 205 patients who received canal wall-down tympanoplasty with ossicular chain reconstruction were randomized into one of the three groups with different MEPA. Group 1 (n=72) received MeroGel as the MEPA, Group 2 (n=64) cartilage, and Group 3 (n=69) both. Air conduction (AC) and bone conduction (BC) thresholds at 0.5, 1, 2, and 4 kHz were measured, and air-bone gaps (ABG) were analyzed before and after the surgery for each patient. Results: Mean pre- and post-operative ABG was 30.9 dB and 17.6 dB in Group 1, 31.4 dB and 21.9 dB in Group 2, and 32.2 dB and 19.1 dB in Group 3. The ABG closure was 13.3 ± 7.5 in Group 1, 9.5 ± 5.9 in Group 2, and 13.1 ± 9.3 in Group 3. The improvement of ABG after surgery was statistically significant in all three groups (p<.05). The ABG closure was statistically significantly smaller in Group 2 than in other two groups (p<.05). Conclusions: Tympanoplasty using esterified hyaluronic acid (i.e. MeroGel) or cartilage as the MEPA resulted in improved hearing for patients with conductive hearing loss due to adhesive OM. Using MeroGel as the MEPA appeared to achieve a better post-operative outcome than using cartilage. [ABSTRACT FROM AUTHOR]

This article discusses the physiology of normal hearing, the pathophysiology and differential diagnoses of sudden sensorineural hearing loss, and an approach for definitive diagnosis and treatment. A focus is placed on idiopathic sudden sensorineural hearing loss in the adult population in a primary care setting. [ABSTRACT FROM AUTHOR]

Comparative auditory studies make it possible both to understand the origins of modern ears and the factors underlying the similarities and differences in their performance. After all lineages of land vertebrates had independently evolved tympanic middle ears in the early Mesozoic era, the subsequent tens of millions of years led to the hearing organ of lizards, birds, and mammals becoming larger and their upper frequency limits higher. In extant species, lizard papillae remained relatively small (<2 mm), but avian papillae attained a maximum length of 11 mm, with the highest frequencies in both groups near 12 kHz. Hearing-organ sizes in modern mammals vary more than tenfold, up to >70 mm (made possible by coiling), as do their upper frequency limits (from 12 to >200 kHz). The auditory organs of the three amniote groups differ characteristically in their cellular structure, but their hearing sensitivity and frequency selectivity within their respective hearing ranges hardly differ. In the immediate primate ancestors of humans, the cochlea became larger and lowered its upper frequency limit. Modern humans show an unusual trend in frequency selectivity as a function of frequency. It is conceivable that the frequency selectivity patterns in humans were influenced in their evolution by the development of speech. [ABSTRACT FROM AUTHOR]

The ear is one of the most complex organs in the human body. Sound is a sequence of pressure waves, which propagates through a compressible media such as air. The pinna concentrates the sound waves into the external auditory meatus. In this canal, the sound is conducted to the tympanic membrane. The tympanic membrane transforms the pressure variations into mechanical displacements, which are then transmitted to the ossicles. The vibration of the stapes footplate creates pressure waves in the fluid inside the cochlea; these pressure waves stimulate the hair cells, generating electrical signals which are sent to the brain through the cochlear nerve, where they are decoded. In this work, a three-dimensional finite element model of the human ear is developed. The model incorporates the tympanic membrane, ossicular bones, part of temporal bone (external auditory meatus and tympanic cavity), middle ear ligaments and tendons, cochlear fluid, skin, ear cartilage, jaw and the air in external auditory meatus and tympanic cavity. Using the finite element method, the magnitude and the phase angle of the umbo and stapes footplate displacement are calculated. Two slightly different models are used: one model takes into consideration the presence of air in the external auditory meatus while the other does not. The middle ear sound transfer function is determined for a stimulus of 60 dB SPL, applied to the outer surface of the air in the external auditory meatus. The obtained results are compared with previously published data in the literature. This study highlights the importance of external auditory meatus in the sound transmission. The pressure gain is calculated for the external auditory meatus. [ABSTRACT FROM AUTHOR]

Conclusion:It was found that JIR children had potential sensory neural hearing loss and vestibular affection. Therefore, this study recommends: early complete audiologic evaluation of JIA child followed by regular follow-up, including TOAEs, extended high-frequency audiometry, and VNG. This follow-up is important for preliminary diagnosis and management in order to prevent the negative impact of hearing loss on a child’s life. Objective:The aim of this study was to assess hearing in children with Juvenile idiopathic arthritis (JIA) and compare them with a healthy control group. In addition to conventional audiometry, extended high-frequency audiometry and Transient otoacoustic emission (TOAEs) were used. This study also tried to investigate the vestibular function in JIR children by videonystagmography (VNG). Patients and methods:The study group comprised of 28 children with JIR and 28 healthy children. All subjects were examined audiologically using basic audiological evaluation, high-frequency audiometry, TOAEs, and VNG. Results:Children with JIR had apparent normal peripheral hearing in conventional audiometry; sub-clinical sensory neural hearing loss was detected. This sub-clinical hearing loss appeared in statistically significant difference between them and normal in high-frequency audiometry and TOAEs. VNG test results showed affected tracking and second tests. [ABSTRACT FROM PUBLISHER]

Frogs, and related amphibians, are adapted to live in both air and water, and so good hearing in both mediums is required. The structure of the frog ear can therefore provide a useful perspective on how sound is sensed and the physical principles involved in hearing. This broad survey of the literature highlights two noteworthy aspects of the frog ear and brings them together into a single framework. First, the frog ear contains an arrangement of sensing cells which is difficult to understand: although they are meant to detect sound, the cells are hidden away in recesses and further shielded from incoming sound by a number of short-circuits' in the vibratory pathway. Second, there is the operculum, a moveable plate that fits into the oval window adjacent to the stapes and whose function remains controversial. Both these challenging features can be understood by noting that all sounds carry both pressure and displacement components, and that form and function can be matched by focusing on the pressure component, which to date has been largely overlooked. This paper proposes that the hair cells at the core of the system respond more sensitively to pressure than to displacement. Building on this property, the piston-like operculum, operated by the opercularis muscle, is put forward as a mechanism for adjusting the static hydraulic pressure within the otic capsule, in this way controlling the global sensitivity, or gain, of the sensing cells within. Both these hypotheses have wider implications for understanding hearing in vertebrates. [ABSTRACT FROM AUTHOR]

The inner ear of mammals consists of the cochlea, which is involved with the sense of hearing, and the vestibule and three semicircular canals, which are involved with the sense of balance. Although different regions of the inner ear contribute to different functions, the bony chambers and membranous ducts are morphologically continuous. The gross anatomy of the cochlea that has been related to auditory physiologies includes overall size of the structure, including volume and total spiral length, development of internal cochlear structures, including the primary and secondary bony laminae, morphology of the spiral nerve ganglion, and the nature of cochlear coiling, including total number of turns completed by the cochlear canal and the relative diameters of the basal and apical turns. The overall sizes, shapes, and orientations of the semicircular canals are related to sensitivity to head rotations and possibly locomotor behaviors. Intraspecific variation, primarily in the shape and orientation of the semicircular canals, may provide additional clues to help us better understand form and function of the inner ear. [ABSTRACT FROM AUTHOR]

Older adults with hearing loss who receive care in the noisy environment of a critical care unit can be disadvantaged in their ability to understand speech, thus limiting their participation in decision making. Providing optimal outcomes for such patients can be understood through use of the American Association of Critical-Care Nurses Synergy Model. When older adults are admitted to a critical care unit, their spouses, children, and friends are in positions to participate in the patients' care. The AACN Synergy Model patient characteristic of participation in care is useful in enhancing optimal outcomes for older patients. [ABSTRACT FROM AUTHOR]

Auditory development in the fetus and infant entails the structural parts of the ears that develop in the first 20 weeks of gestation, and the neurosensory part of the auditory system develops primarily after 20 weeks'' gestational age. The auditory system becomes functional at around 25 weeks'' gestation. The cochlea of the middle ear and the auditory cortex in the temporal lobe are most important in the development of the auditory system. They are both easily affected by the environment and care practices in the newborn intensive care unit (NICU). The period from 25 weeks'' gestation to 5 to 6 months of age is most critical to the development of the neurosensory part of the auditory system. This is the time when the hair cells of the cochlea, the axons of the auditory nerve, and the neurons of the temporal lobe auditory cortex are tuned to receive signals of specific frequencies and intensities. Unlike the visual system, the auditory system requires outside auditory stimulation. This needs to include speech, music, and meaningful sounds from the environment. The preterm as well as the term infant cannot recognize or discriminate meaningful sounds with background noise levels greater than 60 dB. The more intense the background noise, especially low frequency, the fewer specific frequencies (pitch) can be heard and used to tune the hair cells of the cochlea. Continuous exposure to loud background noise in the NICU or home will interfere with auditory development and especially frequency discrimination. The initial stimulation of the auditory system (speech and music) needs to occur in utero or in the NICU to develop tonotopic columns in the auditory cortex and to have the critical tuning of the hair cells of the cochlea occur. The control of outside noise, the exposure to meaningful speech sounds and music, and the protection of sleep and sleep cycles, especially rapid eye movement sleep, are essential for healthy auditory development. The environment and care practices for the fetus in utero or the infant in the NICU are critical factors in the development of the auditory system. [Copyright &y& Elsevier]

Abstract: The auditory anatomy of the Florida manatee (Trichechus manatus latirostris) was investigated using computerized tomography (CT), three-dimensional reconstructions, and traditional dissection of heads removed during necropsy. The densities (kg/m3) of the soft tissues of the head were measured directly using the displacement method and those of the soft tissues and bone were calculated from CT measurements (Hounsfield units). The manatee’s fatty tissue was significantly less dense than the other soft tissues within the head (p <0.05). The squamosal bone was significantly less dense than the other bones of the head (p <0.05). Measurements of the ear bones (tympanic, periotic, malleus, incus, and stapes) collected during dissection revealed that the ossicular chain was overly massive for the mass of the tympanoperiotic complex. [Copyright &y& Elsevier]

The author reflects on the significance of the renewed interest in the study of the effects of age, noise exposure, and genetics on the vestibular system and the auditory system in 2021. He cites an increase in studies on the effects of environmental factors or disorders on the systems. He mentions a study on noise exposure and cervical vestibular-evoked myogenic potential. He notes his plan to bring his hearing protection in a football game to protect his hearing and vestibular function.

Self-adjustment of hearing aid gain can provide valuable information about the gain preferences of individual listeners, but these preferences are not well understood. Listeners with mild-to-moderate hearing loss used self-adjustment to select amplification gain and compression parameters in real time on a portable touch screen device while listening in quiet and noisy backgrounds. Adjustments to gain prescribed by the National Acoustics Laboratories' non-linear fitting procedure (NAL-NL2) showed large between-subject variability. Known listener characteristics (age, gender, hearing thresholds, hearing aid experience, acceptable noise level, and external ear characteristics) and listener engagement with the self-adjustment software were examined as potential predictors of this variability. Neither listener characteristics nor time spent adjusting gain were robust predictors of gain change from NAL-NL2. Listeners with less than 2 years of hearing aid experience and who also had better hearing thresholds tended to select less gain, relative to NAL-NL2, than experienced hearing aid users who had poorer thresholds. Listener factors explained no more than 10% of the between-subject variance in deviation from NAL-NL2, suggesting that modifying prescriptive fitting formulae based on the factors examined here would be unlikely to result in amplification parameters that are similar to user-customized settings. Self-adjustment typically took less than 3 min, indicating that listeners could use comparable technology without a substantial time commitment. [ABSTRACT FROM AUTHOR]

The article discusses the convergent evolution of hearing. Topics include a evolution study within the issue by F. Montealegre-Z. et al showing the similarities of the functional and anatomical aspects of hearing in a rainforest insect to that in humans, a diagram illustrating convergent evolution of the hearing mechanism in humans and katydids, and the implication of the discovery of the hearing anatomy in an insect, such as a reevaluation of the phylogenetic spread of sensitive hearing and frequency tonotopy in insects and invertebrates.

The article focuses on the features and function of the ears of mosquitoes. The mosquitoes have a pair of large, wraparound eyes, and projecting from the front of its face is a pair of long and hairy antennae. Each antenna arises from a large, spheroidal base, the Johnston's organ. The mosquitoes' ears are insensitive to pressure fluctuations in the acoustic far field.

The article reviews the book "The Hearing Sciences," 2nd Edition," by Teri A. Hamill and Lloyd L. Price.

Reports on the importance of individualization of ear prints of a person, in forensic research. Significance of the variation in applied force to the surface, in determining the variation in ear prints; Report of lower level of intra-individual variation than inter-individual variation; Importance of anatomical composition of ear; Aspects of elevation and flexibility of the structures of auricle.