Artificial Ear Research Articles

Intelligent Song Recognition via a Hollow-Microstructure-Based, Ultrasensitive Artificial Eardrum.

Artificial ears with intelligence, which can sensitively detect sound-a variant of pressure-and generate consciousness and logical decision-making abilities, hold great promise to transform life. However, despite the emerging flexible sensors for sound detection, most success is limited to very simple phonemes, such as a couple of letters or words, probably due to the lack of device sensitivity and capability. Herein, the construction of ultrasensitive artificial eardrums enabling intelligent song recognition is reported. This strategy employs novel geometric engineering of sensing units in the soft microstructure array (to significantly reduce effective modulus) along with complex song recognition exploration leveraging machine learning algorithms. Unprecedented pressure sensitivity (6.9 × 103 kPa-1) is demonstrated in a sensor with a hollow pyramid architecture with porous slants. The integrated device exhibits unparalleled (exceeding by 1-2 orders of magnitude compared with reported benchmark samples) sound detection sensitivity, and can accurately identify 100% (for training set) and 97.7% (for test set) of a database of the segments from 77 songs varying in language, style, and singer. Overall, the results highlight the outstanding performance of the hollow-microstructure-based sensor, indicating its potential applications in human-machine interaction and wearable acoustical technologies.

A Nanoparticle-Based Artificial Ear for Personalized Classification of Emotions in the Human Voice Using Deep Learning.

Artificial intelligence and human-computer interaction advances demand bioinspired sensing modalities capable of comprehending human affective states and speech. However, endowing skin-like interfaces with such intricate perception abilities remains challenging. Here, we have developed a flexible piezoresistive artificial ear (AE) sensor based on gold nanoparticles, which can convert sound signals into electrical signals through changes in resistance. By testing the sensor's performance at both frequency and sound pressure level (SPL), the AE has a frequency response range of 20 Hz to 12 kHz and can sense sound signals from up to 5 m away at a frequency of 1 kHz and an SPL of 126 dB. Furthermore, through deep learning, the device achieves up to 96.9% and 95.0% accuracy in classification and recognition applications for seven emotional and eight urban environmental noises, respectively. Hence, on one hand, our device can monitor the patient's emotional state by their speech, such as sudden yelling and screaming, which can help healthcare workers understand patients' condition in time. On the other hand, the device could also be used for real-time monitoring of noise levels in aircraft, ships, factories, and other high-decibel equipment and environments.

Human-centered Artificial Intelligence Development

Few researchers provide a wider vision of artificial feet, hands, mouths, eyes, ears, and brains. This limits our vision of them and their significant impacts on the modern Industrial Revolution and Artificial Intelligence (AI) history. This article presents a novel perspective on human-centered social development starting from artificial feet. After briefly reviewing AI, this article explores the age of AI and artificial feet, hands, mouths, eyes, ears, and brains. It also applies AI to artificial feet and artificial brains. The research reveals that artificial feet are one of the origins of the Industrial Revolution and a real foundation of AI. The study demonstrates that artificial feet and brains liberate our body and society, whereas from artificial brains to artificial feet is control of our body and society. This article also looks at AI's trends and challenges. The approach in this article will facilitate the research and development of big data, analytics, and intelligences.

Unsealed Piezoelectric MEMS Speaker with Rigid-Flexible Composite Membrane

Abstract In this paper, we propose an unsealed piezoelectric microelectromechanical systems (MEMS) speaker with rigid-flexible composite membrane, which can eliminate the membrane separation and the vibration displacement limitation at high driving voltage compared to that with the sealed rigid-flexible coupling membrane demonstrated in our previous work. Measurements performed on encapsulated prototypes mounted to an artificial ear simulator have revealed that in the human audible range of 20 Hz-20 kHz, higher than 68.5 dB SPL are obtained at 2 V, and greater than 89.6 dB SPLs are achieved at 10 V. Moreover, the SPL distribution and effective SPLs at each moment when playing the same song exhibit similar characteristics to those of a commercial electromagnetic one. This piezoelectric MEMS speaker achieves high SPLs meeting the basic hearing needs of the human, and will have excellent prospects for future wearable audio electronics.

Meta-earplugs: Innovative concepts for alleviating the occlusion effect

Passive earplugs are commonly used to reduce workers' exposure to excessively high noise levels. Yet, they are associated with various discomforts of diverse origins (e.g., acoustic, physical, functional, or psychological). The occlusion effect, characterized by an increased perception of physiological sounds transmitted through bone conduction to the cochlea, presents a challenge, leading to acoustic discomfort, especially at low frequencies (0.1 to 1 kHz) and for shallow or moderate insertion depths of the earplug. Building upon acoustic meta-material principles, this study presents “meta-earplug” concepts designed to alleviate the occlusion effect. The approach focuses on reducing the input impedance of the earplug medial surface either to the characteristic impedance of air, using broadband perfect absorption, or to the acoustic impedance of the open ear canal, resulting in a zero objective occlusion effect. For these purposes, the proposed meta-earplug concepts are made of Helmholtz resonators arranged in parallel or series. Transfer matrix models are used in an optimization process to refine the geometry of the meta-earplugs. Although meta-earplug concepts involving multiple Helmholtz resonators have been preliminarily assessed using an artificial ear, a meta-earplug featuring a single resonator has undergone testing with human participants. The evaluation encompasses both objective measurements and subjective assessments.

DeepEar: Sound Localization With Binaural Microphones

The binaural microphone, which refers to a pair of microphones with artificial human-shaped ears, is widely used in hearing aids and spatial audio recording to improve sound quality. It is crucial for such devices to find the voice direction in many applications such as binaural sound enhancement. However, sound localization with two microphones remains challenging, especially in multi-source scenarios. Most previous work utilized microphone arrays to deal with the multi-source localization problem. Extra microphones yet have space constraints for deployment in many scenarios ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">e</i> . <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</i> ., hearing aids). Inspired by the fact that humans have evolved to locate multiple sound sources with only two ears, we propose DeepEar, a binaural microphone-based sound localization system. To this end, we design a multisector-based neural network to locate multiple sound sources simultaneously, where each sector is a discretized region of the space for different angle of arrivals. DeepEar fuses explicit hand-crafted features and implicit latent sound representatives to facilitate sound localization. More importantly, the trained DeepEar model can adapt to new environments with a minimum amount of extra training data. The experiment results show that DeepEar substantially outperforms the state-of-the-art binaural deep learning approach by a large margin in terms of sound detection accuracy and azimuth estimation error.

Effective rehabilitation of auricular defects with two different prosthetic materials: case reports

A person’s face being a visible element, instant physical care and mental support is mandatory for patients affected with maxillofacial defects. Defects in noticeable locations like the ear create a lacuna which deteriorates the quality of life of the victims. Immediate restoration of the defect with artificial prosthesis becomes crucial. Two such cases of acquired auricular defects rehabilitated with maxillofacial prosthesis are described in this manuscript. This case report briefs about two patients with auricular defects reported for restoration. Case one had a congenital agenesis of his right ear whereas case two presented with a history of trauma. Immediate management with artificial ear prosthesis was decided to restore the patients to normalcy of life. Hence an effective restoration was carried out using maxillofacial auricular prosthesis made from medical grade silicone and acrylic. They were retained onto to the residual external structures.

Method to measure the effect of acoustic leaks on active noise reduction device performance

Passive hearing protection (HP) systems are designed to reduce the level of noise at the ear. Passive HP typically excel in attenuating mid- to high-frequency noise. Active noise reduction (ANR) has the potential to provide additional attenuation of low-frequency noise. There are documented reports describing unwanted sound being generated by ANR systems if an acoustic leak is present. The objective of this effort was to develop a method to measure the performance of ANR devices with and without the introduction of an acoustic leak. A number of ANR earcups were selected for this study. Data were collected with an artificial ear and a flat base plate in a noise environment that ranged from 65–115 dB SPL. Wedges, designed in-house, created a consistent acoustic leak that ranged in size from 1–2 mm in radius. The results revealed that some ANR earcups provided high levels of protection when the earcup was well-sealed; however, when an acoustic leak was introduced, the earcups became unstable and generated noise in the earcup. This instability was not seen in all ANR devices. The outcome of these measurements solidified the need for a method to measure ANR device performance when acoustic leaks are introduced.

Passive earplug including Helmholtz resonators arranged in series to achieve broadband near zero occlusion effect at low frequencies.

The use of passive earplugs is often associated with the occlusion effect: a phenomenon described as the increased auditory perception of one's own physiological noise at low frequencies. As a notable acoustic discomfort, the occlusion effect penalizes the use and the efficiency of earplugs. This phenomenon is objectively characterized by the increase in sound pressure level in the occluded ear canal compared to the open ear canal. Taking inspiration from acoustic metamaterials, a new design of a three-dimensional printed "meta-earplug," made of four Helmholtz resonators arranged in series, is proposed for achieving near zero objective occlusion effect measured on artificial ear in a broadband frequency range (300 Hz to 1 kHz). For this purpose, the geometry of the meta-earplug is optimized to achieve a null occlusion effect target based on an analytical model of the phenomenon. It results from the optimization process that the input impedance of the meta-earplug medial surface approximately matches the input impedance of the open ear canal, weighted by the ratio of volume velocity imposed by the ear canal wall to the ear canal cavity between open and occluded cases. Acoustic properties of the meta-earplug are also shown to significantly improve its sound attenuation at the piston-like mode of the system.

Frequency Selectivity via Inner Boundary Conditions for A Self‐Powered Multiresonant Acoustic Sensing Array with Broad Bandwidth

AbstractThis study investigates and proposes innovative approaches to achieve frequency selectivity within a limited space. Traditional multiresonant acoustic devices use individual sensing elements of varying sizes to achieve resonance frequency (fr), leading to an inability to sense focused acoustic waves, unlike the human ear. A miniaturized, self‐powered artificial basilar membrane that incorporates multiresonant features is introduced. Multiple fr of the diaphragms are developed using inner boundary conditions (iBCs) defined by an adjustable micropatterned elastomeric support (µ‐support) and a porous nanofiber (NF) mat. This new approach offers the advantage of all‐in‐one fabrication, eliminating the need for device area variation or an additional rigid frame typically required in conventional multiresonant acoustic devices. The efficacy of the iBCs in shifting fr within the vocal frequency ranges is verified via a laser Doppler vibrometer, simulation, and triboelectric output. With its self‐powering capabilities based on triboelectric principles, this artificial basilar membrane holds promise for accurately recognizing musical and vocal signals with specific frequency characteristics. With four different iBCs in a total device area of 23 × 23 mm2, a tunable four‐channel system with fr ranging from 400 to 3000 Hz is achieved. This advancement enables the sensing of focused acoustic waves, simulating the functionality of an artificial human ear model.

Electronic Auscultation System: a Method for Measuring the Amplitude-Frequency Characteristics of Stethoscopes

The purpose of research is increasing the diversity of designs of electronic auscultation systems with measured characteristics and testing. A series of articles includes the development of a model of an electronic auscultation system, the development of an electronic stethoscope design, the manufacture of an experimental sample, the development of a method for measuring the amplitude-frequency characteristics of electronic and classical stethoscopes, testing the proposed models and methods, and analyzing auscultatory data. The article proposes a method for measuring the frequency response of classical and electronic stethoscopes. The proposed method was tested. The frequency response of classical and electronic stethoscopes was measured. The design of the head of the electronic stethoscope has been improved, the frequency response of the original and improved designs has been compared. Methods. The studies were based on methods for measuring the frequency characteristics of electroacoustic transducers proposed in interstate standards. On the basis of methods in interstate standards, a simplified method for measuring the amplitude-frequency characteristics of electronic stethoscopes has been developed. The following equipment was used in the study: Type 4227 "Artificial Mouth" emitter from Bruel &amp; Kjaer; measuring condenser microphone "Artificial ear" Type 4146 with a 2CC reference chamber from Bruel &amp; Kjaer; Type 2118 analyzer from Bruel &amp; Kjaer. Results. The amplitude-frequency characteristics of classical and electronic stethoscopes are obtained. The design of the electronic stethoscope head has been improved, the amplitude-frequency characteristics of the original and improved designs have been compared. Conclusion. A method for measuring the parameters of the frequency characteristics of the sound pressure level of classical and electronic stethoscopes is proposed. The method is as close as possible to the standardized methods for monitoring acoustic parameters, while being sufficiently simple and cheap compared to the pressure measurement method, demonstrating the qualitative similarity of the measurement results.

Evaluation of Noise Exposure and Hearing Threshold Levels Among Call Centre Operators

The aim of this study was to evaluate the hearing status of call centre operators in relation to their noise exposure. Conventional pure-tone audiometry and extended high-frequency audiometry were performed in 49 workers, aged 22–47 years (mean ± SD: 32.0 ± 6.0 years), working in call centre from 1.0 to 16.5 years (mean ± SD: 4.7 ± 2.9 years). Questionnaire inquiry aimed at collecting personal data, the information on ommunication headset usage habits, self-assessment of hearing ability and identification of risk factors for noise-induced hearing loss were also carried out. Sound pressure levels generated by the communication headset were determined using the artificial ear technique specified in CSA Z107.56-13 (2013) standard. The background noise prevailing in offices was also measured according to PN-N-01307 (1994) and PN-EN ISO 9612 (2011). Personal daily noise exposure levels in call centre operators varied from 66 to 86 dB (10–90th percentile). About half of the study subjects had normal hearing in the standard frequencies (from 250 to 8000 Hz) in both ears, while only 27.1% in the extended high-frequencies (9–16 kHz). Moreover, both high-frequency and speech-frequency hearing losses were observed in less than 10% of audiograms, while the extended high-frequency threshold shift was noted in 37.1% of analysed ears. The hearing threshold levels of call centre operators in the frequency of 0.25–11.2 kHz were higher (worse) than the expected median values for equivalent (due to age and gender) highly screened population specified in ISO 7029 (2017). Furthermore, they were also higher than predicted for 500–4000 Hz according to ISO 1999 (2013) based on the results of noise exposure evaluation.

A Piezoelectric MEMS Speaker with a Combined Function of a Silent Alarm.

To explore the versatility of speakers, a piezoelectric micro-electro-mechanical system (MEMS) speaker combining the function of a silent alarm is proposed, which mainly comprises a lead zirconate titanate (PZT) actuation layer and a rigid-flexible coupling supporting layer. Measurements performed on encapsulated prototypes mounted to an artificial ear simulator have revealed that, compared to a speaker with a rigid supporting layer, the sound pressure level (SPL) of the proposed piezoelectric MEMS speaker with a rigid-flexible coupling supporting layer is significantly higher and is especially higher by 4.1-20.1 dB in the frequency range from 20 Hz to 4.2 kHz, indicating that the rigid-flexible coupling supporting layer can improve the SPL significantly in low frequency. Moreover, the spectral distribution characteristic of its playback audio is similar to that of the commercial electromagnetic type. The device can also function as a silent alarm based on oral airflows in dangerous situations, as it performs well at recognizing words according to their unique voltage-signal characteristics, and can avoid the effects of external sound noise, body movement, long distance, and occlusion. This strategy provides inspiration for functional diversification of piezoelectric MEMS speakers.

Acoustic platforms meet MXenes - a new paradigm shift in the palette of biomedical applications.

The wide applicability of acoustics in the life of mankind spread over health, energy, environment, and others. These acoustic technologies rely on the properties of the materials with which they are made of. However, traditional devices have failed to develop into low-cost, portable devices and need to overcome issues like sensitivity, tunability, and applicability in biological in vivo studies. Nanomaterials, especially 2D materials, have already been proven to produce high optical contrast in photoacoustic applications. One such wonder kid in the materials family is MXenes, which are transition metal carbides, that are nowadays flourishing in the materials world. Recently, it has been demonstrated that MXene nanosheets and quantum dots can be synthesized by acoustic excitations. In addition, MXene can be used as a mechanical sensing material for building piezoresistive sensors to realize sound detection as it produces a sensitive response to pressure and vibration. It has also been demonstrated that MXene nanosheets show high photothermal conversion capability, which can be utilized in cancer treatment and photoacoustic imaging (PAI). In this review, we have rendered the role of acoustics in the palette of MXene, including acoustic synthetic strategies of MXenes, applications such as acoustic sensors, PAI, thermoacoustic devices, sonodynamic therapy, artificial ear drum, and others. The review also discusses the challenges and future prospects of using MXene in acoustic platforms in detail. To the best of our knowledge, this is the first review combining acoustic science in MXene research.

Morphologic clustering of earcanals using deep learning algorithm to design artificial ears dedicated to earplug attenuation measurement.

Designing earplugs adapted for the widest number of earcanals requires acoustical test fixtures (ATFs) geometrically representative of the population. Most existing ATFs are equipped with unique sized straight cylindrical earcanals, considered representative of average human morphology, and are therefore unable to assess how earplugs can fit different earcanal morphologies. In this study, a methodology to cluster earcanals as a function of their morphologies with the objective of designing artificial ears dedicated to sound attenuation measurement is developed and applied to a sample of Canadian workers' earcanals. The earcanal morphologic indicators that correlate with the attenuations of six models of commercial earplugs are first identified. Three clusters of earcanals are then produced using statistical analysis and an artificial intelligence-based algorithm. In the sample of earcanals considered in this study, the identified clusters differ by the earcanal length and by the surface and ovality of the first bend cross section. The cluster that comprises earcanals with small girth and round first bend cross section shows that earplugs induced attenuation significantly higher than the cluster that includes earcanals with a bigger and more oval first bend cross section.

Graphene‐based dual‐function acoustic transducers for machine learning‐assisted human–robot interfaces

AbstractHuman–robot interface (HRI) electronics are critical for realizing robotic intelligence. Here, we report graphene‐based dual‐function acoustic transducers for machine learning‐assisted human–robot interfaces (GHRI). The GHRI functions both an artificial ear through the triboelectric acoustic sensing mechanism and an artificial mouth through the thermoacoustic sound emission mechanism. The success of the integrated device is also attributed to the multifunctional laser‐induced graphene, as either triboelectric materials, electrodes, or thermoacoustic sources. By systematically optimizing the structure parameters, the GHRI achieves high sensitivity (4500 mV Pa–1) and operating durability (1 000 000 cycles and 60 days), capable of recognizing speech identities, emotions, content, and other information in the human speech. With the assistance of machine learning, 30 speech categories are trained by a convolutional neural network, and the accuracy reaches 99.66% and 96.63% in training datasets and test datasets. Furthermore, GHRI is used for artificial intelligence communication based on recognized speech features. Our work shows broad prospects for the development of robotic intelligence.image

Regeneration of artificial injuries external ear elastic cartilage of rabbits after stem cells local injection

Introduction: Every year, a large number of patients from developed countries turn to surgical departments with the reconstruction problems of the auricle cartilage. A some of surgical procedures was developed to correct minor defects due to the low regenerative capacity of elastic cartilage. Stem cells can potentially differentiate into chondroblasts and chondrocytes and restore cartilage integrity. Many factors influence on the differentiation and proliferation of stem cells, which complicates the method application. Therefore, the investigation of using stem cells to regeneration elastic cartilage is relevant. Aim: clarification the regeneration features of the artificial defect of the rabbits’ ear elastic cartilage after the stem cells injection. Materials and methods: The investigation was conducted on rabbits of chinchilla breed aged 1.5 months, weighing 2.5 kg. Artificial lesions measuring 2 x 7-10 mm were simulated on the cartilaginous plate of the outer ear with a scalpel. 0.5 ml of stem cell suspension (~5 million) obtained from the umbilical cord of rabbits by enzymatic method was injected into the defect site. Histological sections of the cartilage defect were prepared. The samples were stained by Weigert and Azure II methods. The relative density of collagen, elastin fibers, oxyphilic and basophilic tissue elements was programmatically evaluated. Results and discussion: The amount of fibers in the native elastic cartilage was more on 35% of the relative dermis. The newly formed tissues at the damage cartilage was like to the dermis after 2 months. Similar results were found on ear in 2.5 and 3 months after surgery. Native cartilage on histological sections almost was not oxyphilic. Maybe a significant number of acidic components was masked it. Dense connective tissue contains almost equal amounts of both components. Thus, it is possible to trace changes in the intercellular matrix that will characterize the direction of the regeneration process. The area of elastic cartilage defect was characterized by a significant presence of oxyphilic elements after 2 months of the stem cells addition. The ratio of oxyphilic and basophilic components in the native elastic cartilage was about to zero. For the dermis was 1.4-1.5. Dense scar connective tissue was characterized by a ratio about 1. Based on the results obtained, was assumed that the direction of stem cell proliferation is determined shortly after injection. Conclusion: The addition of stem cells to the area of the artificially created elastic cartilage defect of the rabbit's ear was not allow to obtain stable regenerative processes of cartilage tissue and the restoration of the intercellular matrix to its original state. The process of stem cell differentiation contributes the formation of dense connective tissue of the scar, which may be due to the presence of proinflammatory cytokines, growth factors and other biologically active molecules. This was not creating the necessary conditions for the cartilage regeneration.

Preclinical acoustic efficiency evaluation of bionic ear

Objective. To study the major acoustic properties of the prototype of bionic ear developed in order to confirm its functional performance.&#x0D; Materials and methods. Acoustic properties of the bionic ear were measured using Random Phase MultiSine signal in a test bench, which simulated the implant-emitter-osseous tissue-inner ear system. The resulting pulse response was converted to the target characteristics: FR and group lag. Experiments were carried out for -6dB signal level, 10 times for each of the methods used.&#x0D; Results. Microtia is a congenital auricular hypoplasia or aplasia (anotia) which often involves impairment or total loss of hearing. One way to rehabilitate this type of patients is to use bone-conducting apparatuses (bone anchored hearing aids), which allow to compensate for the functional component but not to restore facial aesthetics. This paper deals with major acoustic properties of the prototype bionic ear we have previously developed, in order to confirm its functional performance for clinical use. Our analysis of acoustic characteristics of the bionic ear system showed the frequency response was uniform enough in extended voice frequency range (100 to 10000 Hz). The experimental research demonstrated that operating time of the prototype bionic ear to battery depletion is 10 h 26 min with 25 % amplification, 10 h 05 min with 50 % amplification, 9 h 48 min with 75 % amplification.&#x0D; Thus, the acoustic characteristics of the vibratory emitter were determined, which confirmed that the bionic artificial ear was eligible for clinical testing.&#x0D; Conclusions. Major frequency response of the vibratory emitter was measured, and confirmed that preclinical studies were successful and the bionic ear was eligible for clinical testing.

Effect of shapes of reconstructed middle ear on sound transmission

The conductive hearing loss, which are caused by malfunctions of some parts along the auditory transmission path, quite decreases the quality of life. The conductive hearing loss is caused by a variety of defects or injuries such as the chronic otitis media, osteosclerosis, and malformation of ossicle. In such cases, the defected bones of the middle ear are often surgically reconstructed by using the artificial ear ossicles in order to increase the hearing ability. However, some artificial ear ossicles cannot work well, and the surgical procedure does not result in an increase of hearing, especially in such a difficult case of symptom, when only the bottom plate of the stapes are remained and all of the other bones are destroyed. Herein, the appropriate shapes of the artificial ear ossicle, which are suitable for various cases of the middle ear defects, can be determined by adopting the numerical prediction of the vibroacoustic transmission of sounds via the bones. In this study, the vibroacoustic transmission characteristics via the bone models of the human middle ear are calculated by using the finite-element method (FEM).

A 3D printed patient specific artificial outer ear model for use in auricle reconstruction surgery: a clinical feasibility study

Auricle reconstruction is a routine surgery in the field of Otolaryngology but the design of the reconstruction is based on the clinicians guess of the correct previous anatomy. Using additive manufacturing processes to build a model the surgeon can refer to may be a good substitute for conventional surgery. The quality of the framework replicating the three-dimensional architecture of the ear and precise sculpting of the anatomical structures are necessary in order to reach a desired outcome. In this work we present the workflow to produce an individualized 3D outer ear model for use in auricle reconstruction surgery and report on the clinical application of this model in a particular patient reconstruction surgery.