Sound Amplification Research Articles

Metabolic and Sensory Components of Age-Related Hearing Loss.

Age-related hearing loss is a multifactorial condition with effects of aging and environmental exposures that contribute to cochlear pathologies. Metabolic hearing loss involves declines in the endocochlear potential, which broadly reduce cochlear amplification of low-level sounds. Sensory hearing loss involves damage to outer hair cells that may eliminate amplification, especially for high-frequency sounds. A novel approach was developed to estimate the extent of metabolic and sensory components (in dB) for an individual, by combining hearing loss profiles to optimally approximate their hearing thresholds (audiogram). This approach was validated using estimates of metabolic and sensory hearing loss from retrospective datasets including gerbils, cross-sectional and longitudinal audiograms from older adults, a measure of speech recognition in noise, and histopathology case reports. Simulation results showed that well-approximated audiograms can produce accurate metabolic and sensory estimates. Estimates of metabolic and sensory components of age-related hearing loss differentiated gerbils with known strial and/or sensory pathologies based on age and exposures. For older adults, metabolic estimates consistently increased with age and were associated with poorer speech recognition in noise, while sensory estimates were related to sex and noise exposure differences. Histopathology case reports (with audiograms) that described strial and outer hair cell pathology in temporal bones from older donors showed significant differences in metabolic and sensory estimates, respectively. The results support the view that audiograms include information that can be used to estimate the metabolic and sensory components of age-related hearing loss.

Superior semicircular canal dehiscence repair with small middle fossa craniotomy using an oto-microscopic and co-endoscopic assisted approach.

Superior semicircular canal dehiscence is an uncommon neurotological disorder in which the petrous temporal bone overlying the superior semicircular canal lacks bone. Its most common symptoms include amplification of internal sounds, autophony, tinnitus, sound- and pressure-induced vertigo, hyperacusis, oscillopsia, and hearing loss. This video presentation aimed to demonstrate endoscopic-assisted repair of superior semicircular canal dehiscence with middle fossa craniotomy. Eleven patients with superior semicircular canal dehiscence, verified with temporal computed tomography, were enrolled in the study. An endoscopy-assisted middle fossa approach was applied to all patients. Superior semicircular canal dehiscence was successfully repaired with an endoscope in 11 patients. Endoscopic-assisted repair of superior semicircular canal dehiscence may be a superior approach compared with binocular operative microscopy.

Datox

Datox explores the imperceptible electromagnetic radiation generated by elec- tronics and digital technologies as sonic material. The work is a music album and a live performance that creates an audiovisual environment that explores sonic possibilities through the amplification of imperceptible sounds. This aims to highlight a material layer that comes before data, the electricity that powers electronic devices. The music album and performance immerse the listener in a sonic environment of non-human agency, the electricity and its voltage differences at the circuitry level of computational devices. The work exposes the dependency of computational societies on energy production from non-re- newable sources such as coal that contribute to environmental pollution and the climate crisis.

Occlusion Effect Cancellation in Headphones and Hearing Devices—The Sister of Active Noise Cancellation

The perception of one’s own voice influences the acceptance of hearing devices, such as headphones, headsets or hearing aids. When these devices fully or partially occlude the ear canal, the wearer’s own voice sounds boomy or like talking in a barrel. This is called <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">occlusion effect</i> . Occluding the ear canal results in an amplification of body-conducted sounds, mainly at low frequencies, and an attenuation of air-conducted sounds, predominantly at high frequencies, compared to the open ear. This contribution provides a comprehensive treatment of Occlusion Effect Cancellation (OEC) and its relation to Active Noise Cancellation (ANC) using digital signal processing. A novel effective filter structure is presented which offers some degree of adaptability and adjustability. Furthermore, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">digitally opening</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">closing</i> the ear is evaluated by listening tests and objective measurements.

Hearing and Speech Perception for People With Hearing Loss Using Personal Sound Amplification Products.

BackgroundHearing loss (HL) is the most common chronic disease and has been linked to negative health outcomes. Hearing aids (HAs) are regarded as the gold standard for HL management, however, the adoption rate of HAs is relatively low for various reasons. With this background, hearing devices, such as personal sound amplification products (PSAPs) received significant attention as an alternative to conventional HAs. This study aimed to evaluate the clinical efficacy of PSAPs in patients with mild to moderately severe HL.MethodsNineteen patients with mild hearing loss (MHL), 23 with moderate hearing loss (MDHL), and 15 with moderately severe hearing loss (MSHL) participated in the study. Electroacoustic analysis, simulated real-ear measurements (REMs), and three clinical evaluations were implemented.ResultsAll devices satisfied the electroacoustic tolerances. All devices provided sufficient gain for MHL and MDHL audiograms. However, in MSHL audiogram, the gains of PSAPs were insufficient, especially for high frequencies. In terms of clinical evaluations, sound-field audiometry showed significant improvements between aided and unaided thresholds in all groups for all devices (P < 0.001). Significant improvements of word recognition scores were only shown for HAs between aided and unaided conditions. The Korean version of the Hearing In Noise Test did not show any consistent findings for all devices and groups.ConclusionCertain PSAPs are beneficial for improving hearing and speech perception in patients with HL. Well-chosen PSAPs could be an alternative hearing rehabilitation option for these patients.

The benefit of hearing aids in adults with hearing loss during the Covid–19 pandemic

Background/Aim: Hearing aids, cochlear implants, and guidance are highly effective in improving communication skills and the quality of life of individuals with hearing loss. During the Covid-19 pandemic, patients with hearing loss, especially those living far from city centers, faced insufficient device use due to their inability to go to the hospitals and device centers. This study aimed to evaluate the effects of remote monitorization of sound amplification in adults using cochlear implants and/or hearing aids during the lockdown period. Methods: In this cross-sectional study, we recruited 98 individuals with post-lingual cochlear implants (n=38) and hearing aids (n=60). Patients on hearing aids followed before the Covid-19 pandemic were guided with a remote computer connection during the pandemic. All participants filled out the Spatial Hearing Questionnaire (SHQ), the short version of Speech Spatial Quality of Questionnaire (SSQ12), Short Form-36 quality of life questionnaires (SF-36), Satisfaction with Amplification in Daily Life Questionnaire (SADL), and the Coronavirus 19 Phobia Scale (C19P-S) via google questionnaire. Results: During the lockdown period, there were significant increases in the spatial perception scores (SSQ12) of cochlear implant and hearing aid users (P

Dynamic study of tip-link tension and stereocilia motion in cochlea

Explanation of cochlear active acoustic amplification mechanism has been an unsolved medical problem. This mechanism is closely related to the motion of the stereocilia at the top of the outer hair cells in the cochlea. The motion of stereocilia is regulated by the tip-link tension and the fluid force of the lymph fluid. Therefore, studying the tip-link tension during the motion of stereocilia is an important part of the explanation of the cochlea's active sensory sound amplification mechanism. Most of previous studies regarded the stereocilia as rigid bodies, and ignored the influence of shaft bending when studying the mechanical properties of hair bundle. Most of the researches on elastic stereocilia used the finite element simulation, or simplified the model by ignoring the fluid-solid coupling with lymph fluid, or considered only static loading. Based on the Poiseuille flow combined with the distributed parameter model, the analytical solution of the elastic motion of stereocilia is derived in this work. The dynamic response of the stereocilia under the shear force of the tectorial membrane and the change law of tip-link tension are studied. The shaft bending produces a nonlinear accumulation of displacement at the height of the stereocilia. The higher the stereocilia, the more obvious the accumulation effect is. Under the action of dynamic load, the shaft bending contributes most to the displacement response in the tall stereocilium, and this contribution is easily affected by frequency change. Under low frequency load, the displacement response of tall stereocilium comes mainly from the root deflection. At high frequency, the shaft bending increases significantly, and the displacement response is produced by the combination of shaft bending and root deflection. The change of F-actin content in the cochlea exposed to noise would affect the stereocilia stiffness. In this paper, it is found that the decrease of stereociliary Young's modulus will increase the peak value of normalized tension and reduce its peak frequency, and the amplitude of normalized tension will increase under the low frequency shear load. Since the tip-link is connected to an ion channel, the change of normalized tension will affect the probability of ion channels opening, change the ability of cochlea to perceive the sound of corresponding frequency, and then affect the frequency selectivity of hair bundle. Therefore, previous studies of stereocilia regarded as rigid bodies underestimated the response of the cochlea to low-frequency acoustic signals. This model accurately describes the law of tip-link tension and provides a corresponding theoretical explanation for hearing impairment caused by noise environment. Previous experiments have shown that the lymphatic viscous resistance has little effect on the deflection of stereocilia. In this paper, when the viscous resistance is ignored, the tip-link tension changes very little, and when the pressure between the stereocilia is ignored, the tip-link tension changes significantly and the resonance peak of &lt;inline-formula&gt;&lt;tex-math id="M4"&gt;\begin{document}$ {f_2} $\end{document}&lt;/tex-math&gt;&lt;alternatives&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="4-20211105_M4.jpg"/&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="4-20211105_M4.png"/&gt;&lt;/alternatives&gt;&lt;/inline-formula&gt; disappears. Therefore, lymphatic fluid regulates the resonance properties of the tip-link tension by creating the pressure between the stereocilia. The presence of lymphatics is essential for generating the frequency characteristics of the hair bundle. In the low frequency domain, the motion of stereocilia is regulated mainly by tip-link, and in the high frequency domain, it is regulated mainly by lymphatic pressure.

Eléctrico, auténtico y precario: el sonido y los nuevos públicos en los espectáculos de rock de los ochenta montevideanos

During the 1980s, in Montevideo, Uruguay, music and cultural critics constantly lambasted the sound quality at live rock shows. This recurring issue was due to three main factors: the economic challenge of acquiring electronic equipment, the deficiency of sound amplification systems, and the acoustic inadequacy of most venues dedicated to rock shows. In the following paper, we analyze the above criticisms and reflect on the relationship between journalists and musicians, as they debated sound amplification and the alleged crisis of rock music. We also look at the difficulties they faced in characterizing the new youth audiences that had emerged after the democratic transition. The crisis of rock music was sparked by the impossibility of incorporating rock into — and having it be heard within the constraints of — the broader tradition of Uruguayan music. Moreover, characterizing youth audiences proved complicated because of pre-existing notions of audiences as massive and homogenous, typical of the large-scale canto popular concerts during the dictatorship. Following a thorough survey of press coverage between 1984 and 1987, we analyze the statements of journalists and musicians, doing so from the point of view of cultural and acoustic studies. More specifically, we look at the statements made by members of the band Los Tontos, who described their strategies for overcoming economic hurdles and their perception of the period’s new music audiences.&nbsp

Parameter Simulation and Design of an Airborne Hyperspectral Imaging LiDAR System

With continuous technological development, the future development trend of LiDAR in the field of remote sensing and mapping is to obtain the elevation and spectral information of ground targets simultaneously. Airborne hyperspectral imaging LiDAR inherits the advantages of active and passive remote sensing detection. This paper presents a simulation method to determine the design parameters of an airborne hyperspectral imaging LiDAR system. In accordance with the hyperspectral imaging LiDAR equation and optical design principles, the atmospheric transmission model and the reflectance spectrum of specific ground targets are utilized. The design parameters and laser emission spectrum of the hyperspectral LiDAR system are considered, and the signal-to-noise ratio of the system is obtained through simulation. Without considering the effect of detector gain and electronic amplification on the signal-to-noise ratio, three optical fibers are coupled into a detection channel, and the power spectral density emitted by the supercontinuum laser is simulated by assuming that the signal-to-noise ratio is equal to 1. The power spectral density emitted by the laser must not be less than 15 mW/nm in the shortwave direction. During the simulation process, the design parameters of the hyperspectral LiDAR system are preliminarily demonstrated, and the feasibility of the hyperspectral imaging LiDAR system design is theoretically guaranteed in combination with the design requirements of the supercontinuum laser. The spectral resolution of a single optical fiber of the hyperspectral LiDAR system is set to 2.5 nm. In the actual prototype system, multiple optical fibers can be coupled into a detection channel in accordance with application needs to further improve the signal-to-noise ratio of hyperspectral LiDAR system detection.

MANF supports the inner hair cell synapse and the outer hair cell stereocilia bundle in the cochlea.

Failure in the structural maintenance of the hair cell stereocilia bundle and ribbon synapse causes hearing loss. Here, we have studied how ER stress elicits hair cell pathology, using mouse models with inactivation of Manf (mesencephalic astrocyte-derived neurotrophic factor), encoding an ER-homeostasis-promoting protein. From hearing onset, Manf deficiency caused disarray of the outer hair cell stereocilia bundle and reduced cochlear sound amplification capability throughout the tonotopic axis. In high-frequency outer hair cells, the pathology ended in molecular changes in the stereocilia taper region and in strong stereocilia fusion. In high-frequency inner hair cells, Manf deficiency degraded ribbon synapses. The altered phenotype strongly depended on the mouse genetic background. Altogether, the failure in the ER homeostasis maintenance induced early-onset stereociliopathy and synaptopathy and accelerated the effect of genetic causes driving age-related hearing loss. Correspondingly, MANF mutation in a human patient induced severe sensorineural hearing loss from a young age onward. Thus, we present MANF as a novel protein and ER stress as a mechanism that regulate auditory hair cell maintenance in both mice and humans.

Computing and comparative analysis of topological invariants of Y‐junction carbon nanotubes

AbstractRecent findings of diverse forms of carbon nanostructures have encouraged research on their applications in several areas. They are used as a structural material in electronic and optical devices, involving transistors, photodetectors, plastic, biological sensors, pharmaceutical and medicine, and drug delivery systems. Since the discovery of Y‐shaped carbon nanotubes (CNTs) junctions, they have drawn interest for future electron devices, for example, three‐terminal transistors, amplifiers, and switches. A topological index is a number that is used to study the physicochemical properties of chemical structures. In this paper, we are providing topological properties of CNT Y‐junctions. The results obtained for different types of Y‐junction graphs appeared with comparisons. According to the best of our knowledge and literature, this is the first report about topological indices on this class of CNT junctions.

Sound Localization through Multi-Scattering and Gradient-Based Optimization

A gradient-based optimization (GBO) method is presented for acoustic lens design and sound localization. GBO uses a semi-analytical optimization combined with the principle of acoustic reciprocity. The idea differs from earlier inverse designs that use topology optimization tools and generic algorithms. We first derive a formula for the gradients of the pressure at the focal point with respect to positions of a set of cylindrical scatterers. The analytic form of the gradients enhances modeling capability when combined with optimization algorithms and parallel computing. The GBO algorithm maximizes the sound amplification at the focal point and enhances the sound localization by evaluating pressure derivatives with respect to the cylinder positions and then perturbatively optimizing the position of each cylinder in the lens while incorporating multiple scattering between the cylindrical scatterers. The results of the GBO of the uni- and multi-directional broadband acoustic lens designs are presented including several performance measures for the frequency dependence and the incidence angle. A multi-directional broadband acoustic lens is designed to localize the sound and to focus acoustic incident waves received from multiple directions onto a predetermined localization region or focal point. The method is illustrated for configurations of sound hard and sound soft cylinders as well as clusters of elastic thin shells in water.

Exploiting the FM-to-AM conversion to generate high-contrast picosecond laser pulses.

In this work, we simulate and demonstrate experimentally a new approach to generate picosecond laser pulses. This technique is based on optoelectronic FM-to-AM conversion: a transient radiofrequency phase modulation is applied on a continuous-wave fiber laser otherwise blocked by a bandstop filter. By leveraging the ability of modern electronic amplifiers to generate high voltage swings values on a short timescale, the presented setup induces a large and brief excursion out of the filter, hence generating 18 ps pulses with a time contrast of 38 dB. Detailed simulations pave the road toward pulses shorter than 1 ps by using an optimally shaped RF response.

Multi-Zone Active Noise Control Strategy for the Scattered Sound Control of an Infinite Rigid Cylinder

Active noise control can be used to reduce the scattered sound of a reflecting object to make it invisible to incident acoustic waves. For the multi-zone active noise control of scattered sound from an infinite rigid cylinder, an active control strategy is proposed that combines the least absolute shrinkage and selection operator (LASSO) algorithm with constraint points and regularized least squares (RLS) algorithm. The proposed control strategy is used to promote control performance through optimizing the secondary loudspeaker placement of an active noise control system. Compared with the RLS algorithm employing the uniformly placed loudspeakers and the traditional LASSO algorithm, the proposed strategy has better reduction performance both in the forward-scattered and backward-scattered sound target areas, and there is less sound amplification in the far field. From 400 Hz–1100 Hz, the proposed strategy provides a 5 dB–16 dB reduction performance advantage in the target area compared to the RLS algorithm employing uniformly placed loudspeakers.

Acoustic to Electronic and Public to Private: An Introduction to Music in the Great Expansion (1700–2100 CE)

Acoustic to Electronic and Public to Private: An Introduction to Music in the Great Expansion (1700–2100 CE)

Superior Semicircular Canal Dehiscence Revision Surgery Outcomes: A Single Institution's Experience

Superior semicircular canal dehiscence (SSCD) is an abnormality of the otic capsule, which normally overlies the superior semicircular canal. Surgical management is indicated in patients with persistent and debilitating symptoms. Given the complexity of the disease, there are patients who experience less favorable surgical outcomes and require revision surgery. The purpose of this study was to report to the rate of postoperative symptomatic improvement in patients who required revision surgery. A retrospective analysis of patients undergoing SSCD surgical repair at a single institution was performed. Information on patient demographics, primary and secondary surgical approaches, surgical outcomes, and follow-up length was collected. Seventeen patients underwent 20 revision surgeries. There were eleven (65%) females and six (35%) males. Mean age of the cohorts was 50 years (range 30-68 years), and mean follow-up length was 6.8 months (range 0.1-31.1 months). Cerebrospinal fluid leak was noted in 67% of cases. The greatest postoperative symptomatic resolution was reported in oscillopsia (100%), headache (100%), and internal sound amplification (71%), while the least postoperative symptomatic resolution was reported in tinnitus (42%), aural fullness (40%), and dizziness (29%). Revision surgery can provide symptomatic improvement in select SSCD patients; however, patients should be cautioned about the possibility of less favorable outcomes than in index surgery. Revision surgeries are associated with a considerably higher rate of perioperative cerebrospinal fluid leak.

Dual-band piezoelectric acoustic energy harvesting by structural and local resonances of Helmholtz metamaterial

The current study on acoustic energy harvesting is based on a single-band vibroacoustic conversion performed by either structural resonance or local resonance. In this paper, we propose a Helmholtz acoustic metamaterial (HAM) piezoelectric device having dual-band acoustic energy harvesting characteristics. The Helmholtz resonator of the metamaterial amplifies both structural and local resonances. HAM is designed based on the Bloch theorem, plane wave expansion method, and electroacoustic impedance analogy. Numerical simulation is performed to show the sound pressure amplification effect of HAM. A piezoelectric disk is bonded on the point defect of the Helmholtz metamaterial for energy localization and conversion, and HAM is clamped on a self-made experimental platform by simply supported boundary conditions on four sides. The time–frequency image of the voltage output from the swept frequency experiment shows two distinct bands corresponding to the structural resonance frequency of 381 Hz with the band width of 45 Hz and the local resonance frequency of 1526 Hz with the band width of 290 Hz. The peak-to-peak power of HAM is 0.13 mW, and its peak-to-peak voltage is 3.2 V at 391 Hz with the sound pressure of 31 Pa. At the input sound pressure of 23.32 Pa and frequency of 1526 Hz, the output voltage and power are found to be 1.5 V and 0.11 mW, respectively. Under the same amplitude of the input sound pressure, the output power of HAM is found 12.7 times and 4.4 times higher than those of the traditional acoustic metamaterial in the structural and local resonance bands, respectively. Field tests validate the superiority of the designed structure. In the milling environment, the voltage–pressure transmission rate reaches 0.11 V/Pa. The acoustic energy wall composed of HAM will be capable to provide a power solution for an intelligent factory.

Superior Semicircular Canal Dehiscence Outcomes in a Consecutive Series of 229 Surgical Repairs With Middle Cranial Fossa Craniotomy

Superior semicircular canal dehiscence (SSCD) is the appearance of a third mobile window between the middle fossa and the superior semicircular canal. Surgical management is indicated in patients with persistent and debilitating symptoms. The purpose of this study was to evaluate the association between preoperative variables that may impact postoperative symptomatic resolution. A single-institution retrospective analysis was performed on patients who were surgically treated for SSCD. Patients were divided to different cohorts based on unilateral or bilateral nature of the disease. A P value <0.05 was considered statistically significant. A total of 229 surgical repairs were analyzed. Mean age was 51 years (± 7.8 years), and 55.9% of patients were female. All cohorts were similar with respect to baseline demographics. The most commonly reported preoperative symptoms were tinnitus, dizziness, and autophony. The greatest symptomatic resolution was seen in autophony, internal sound amplification, hyperacusis, and oscillopsia. The unilateral SSCD cohort had significantly higher improvement of autophony (P= 0.003), aural fullness (P= 0.05), tinnitus (P= 0.006), hearing loss (P=0.02), dizziness (P= 0.006), and headache (P= 0.007), compared with the bilateral SSCD cohorts. Among patients with bilateral disease, those with unilateral surgery reported greater symptomatic resolution with respect to hyperacusis (P= 0.03), hearing loss (P= 0.02), dizziness (P= 0.03), and disequilibrium (P < 0.001), than those with bilateral operations. Surgical management of SSCD leads to high rates of postoperative symptomatic improvement. Patients with unilateral SSCD benefit greater symptomatic resolution compared to those with bilateral pathology.

Evaluating a Human Ear-Inspired Sound Pressure Amplification Structure with Fabry-Perot Acoustic Sensor Using Graphene Diaphragm.

In order to enhance the sensitivity of a Fabry–Perot (F-P) acoustic sensor without the need of fabricating complicated structures of the acoustic-sensitive diaphragm, a mini-type external sound pressure amplification structure (SPAS) with double 10 μm thickness E-shaped diaphragms of different sizes interconnected with a 5 mm length tapered circular rod was developed based on the acoustic sensitive mechanism of the ossicular chain in the human middle ear. The influence of thickness and Young’s modulus of the two diaphragms with the diameters of 15 mm and 3 mm, respectively, on the amplification ratio and frequency response were investigated via COMSOL acoustic field simulation, thereby confirming the dominated effect. Then, three kinds of dual-diaphragm schemes relating to steel and thermoplastic polyurethanes (TPU) materials were introduced to fabricate the corresponding SPASs. The acoustic test showed that the first scheme achieved a high resonant response frequency with lower acoustic amplification due to strong equivalent stiffness; in contrast, the second scheme offered a high acoustic amplification but reduced frequency range. As a result of sensitivity enhancement, adapted with the steel/TPU diaphragm structure, an optical fiber Fabry–Perot sensor using a multilayer graphene diaphragm with a diameter of 125 μm demonstrated a remarkable sensitivity of 565.3 mV/Pa @1.2 kHz due to the amplification ratio of up to ~29.9 in the range of 0.2–2.3 kHz, which can be further improved by miniaturizing structure dimension, along with the use of microstructure packaging technology.

Design and Preliminary Experiment of W-Band Broadband TE02 Mode Gyro-TWT

The gyrotron travelling wave tube (gyro-TWT) is an ideal high-power, broadband vacuum electron amplifier in millimeter and sub-millimeter wave bands. It can be applied as the source of the imaging radar to improve the resolution and operating range. To satisfy the requirements of the W-band high-resolution imaging radar, the design and the experimentation of the W-band broadband TE02 mode gyro-TWT were carried out. In this paper, the designs of the key components of the vacuum tube are introduced, including the interaction area, electron optical system, and transmission system. The experimental results show that when the duty ratio is 1%, the output power is above 60 kW with a bandwidth of 8 GHz, and the saturated gain is above 32 dB. In addition, parasitic mode oscillations were observed in the experiment, which limited the increase in duty ratio and caused the measured gains to be much lower than the simulation results. For this phenomenon, the reasons and the suppression methods are under study.