Verification and validation of hearing aids:Opportunity not an obstacle

Verification and validation are objective and subjective measurements of hearing aid function. Many studies have provided rationales for performing these measurements as necessary for hearing aid practitioners to provide the highest level of care. Several researchers have suggested that completing these measurements as part of routine clinical care will reduce the number of return visits, reduce the number of aids returned for credit, and increase patient satisfaction. The purpose of this review article is to provide background, method and rationale for practitioners to use these measurements to improve their practice of hearing healthcare.

A comparison of the quality of life of parents of children using hearing aids and those using cochlear implants

Objective:The goal of this study was to evaluate the quality of life of parents of children who use hearing aids(HA)with those who use cochlear implants(CI)in the Indian context and document any differences found.Methods:The Kannada version of the AQoL-4D was administered in a modified fashion to 131 parents(87 HA and 44 CI).Sociodemographic details were collected for supplemental information on the intervention strategy used.Results:A total of 49 parents(29 HA and 20 CI)responded to the questionnaire sent.The mean total scores for both the groups were similar(HA group=17.9(SD=5.5),CI group=17.2(SD=3.4)),as was the score for the first subscale(HA group=8.6(SD=2.9);CI group=8.5(SD=2.6))of the AQoL-4D.No significant differences were found between the two groups on either scores[Total Score:U(N_(HA)=29,NCI=20)=280.5,z=0.194,p>0.05;Subscale 1 Score:U(N_(HA)=29,NCI=20)=281.5,z=-0.176,p>0.05].The degree of hearing loss in the hearing aid group was equivalent to that of the cochlear implant group but this did not appear to influence parental quality of life.Conclusion:Parents of children with hearing aids and cochlear implants appear to be similar on several psychosocial factors in the realms of functional,social,and psychological well-being.In terms of parental quality of life,hearing aids and cochlear implants appear to be equally effective intervention techniques.

SOUND SOURCE LOCALIZATION OF DIGITAL HEARING AIDS USING WAVELET BASED MULTIVARIATE STATISTICAL METHOD

The letter proposed a sound source localization method of digital hearing aids using wavelet based multivariate statistics with the Generalized Cross Correlation (GCC) algorithm. Haar wavelet is used to decompose GCC sequences and extract four wavelet characteristics. And then, Hotelling T2 statistical method is used to fuse the four wavelet characteristics. The statistical value is used to judge the number of sound sources and obtain corresponding time delay estimation which is used to localize the position of sound source. The experimental results show that the proposed method has better robustness in an environment with severe noise and reverberation. Meanwhile, the complexity of al-gorithm is moderate, which is available for sound source localization of hearing aids.

Efficacy of Remote Hearing Aids Programming Using Teleaudiology: A Systematic Review

Telemedicine is defined as a system that allows healthcare workers to deliver their services and consultations to the patients remotely without the need of their physical presence within academic institutions, hospitals, and medical clinics aiming to reduce the personal contact and limiting it to the need only. The field of telemedicine is growing every day and facilitating more flexible services for patients around the world especially during COVID-19 pandemic. Methods: This systematic review was conducted according to the Cochrane Handbook for Systematic Reviews. Database search was made on several databases including PubMed/Medline, Scopus, Web of Science, Publons, EMBASE, and Google Scholar using the relevant keywords. Inclusion criteria for articles in our study included the following original research (primary research articles), addressing the efficacy of teleaudiology for hearing aids programming and satisfaction of patients. Results: Seven studies were included in this systematic review article. Included studies were assessed using Cochrane handbook guidelines. Conclusions: The results of this work based on the currently available literature denote that remote programming for the hearing aids using modern technology is effective and provide comparable results with the standard face-to-face clinic programming, even for patients with no previous experience in hearing aids fitting in either of in-person physical presence programming or remotely over the internet using teleconferencing which is known as teleaudiology. Most of the results were positive and support the continuity to develop better facilities to improve the teleaudiology to be an essential part of hearing aids programming with its different types. Minimal results provided negative impact from the participating patients, this resulted because of the non-upgraded infrastructure and facilities of the audiology clinic or the personal computer of the patient in his home/ workplace or both sides don’t have enough specifications to smoothly perform this modern approach.

Adaptive feedback cancellation based on variable step-size affine projection for hearing aids

A new variable step-size （VSS） affine projection algorithm （APA） （VSS-APA） was proposed for adaptive feedback cancellation suitable for hearing aids. So, a nonlinear function between step-size and estimation error is established and automatically adjusted according to the change of the estimation error, which leads to low misalignment and fast convergence speed. Analysis of the proposed algorithm offers large capacities in converging to the objective system. Simulation shows that the proposed algorithm achieves lower misalignment and faster convergence speed compared to fixed step-size APA and conventional adaptive algorithms.

A sub-milliwatt audio-processing platform for digital hearing aids

We present a novel audio-processing platform, FlexEngine, which is composed of a 24-bit applicationspecific instruction-set processor （ASIP） and five dedicated accelerators. Acceleration instructions, compact instructions and repeat instruction are added into the ASIP＇s instruction set to deal with some core tasks of hearing aid algorithms. The five configurable accelerators are used to execute several of the most common functions of hearing aids. Moreover, several low power strategies, such as clock gating, data isolation, memory partition, bypass mode, sleep mode, are also applied in this platform for power reduction. The proposed platform is implemented in CMOS 130 nm technology, and test results show that power consumption of FlexEngine is 0.863 mW with the clock frequency of 8 MHz at Vdd = 1.0 V.

Investigation of hearing aid users'speech understanding in noise and their spectral-temporal resolution skills

Purpose:Our study aims to compare speech understanding in noise and spectral-temporal resolution skills with regard to the degree of hearing loss,age,hearing aid use experience and gender of hearing aid users.Methods:Our study included sixty-eight hearing aid users aged between 40-70 years,with bilateral mild and moderate symmetrical sensorineural hearing loss.Random gap detection test,Turkish matrix test and spectral-temporally modulated ripple test were implemented on the participants with bilateral hearing aids.The test results acquired were compared statistically according to different variables and the correlations were examined.Results:No statistically significant differences were observed for speech-in-noise recognition,spectraltemporal resolution among older and younger adults in hearing aid users(p>0.05).There wasn’t found a statistically significant difference among test outcomes as regards different hearing loss degrees(p>0.05).Higher performances were obtained in terms of temporal resolution in male participants and participants with more hearing aid use experience(p<0.05).Significant correlations were obtained between the results of speech-in-noise recognition,temporal resolution and spectral resolution tests performed with hearing aids(p<0.05).Conclusion:Our study findings emphasized the importance of regular hearing aid use and it showed that some auditory skills can be improved with hearing aids.Observation of correlations among the speechin-noise recognition,temporal resolution and spectral resolution tests have revealed that these skills should be evaluated as a whole to maximize the patient’s communication abilities.

A 1.4-V 48-μW current-mode front-end circuit for analog hearing aids with frequency compensation

A current-mode front-end circuit with low voltage and low power for analog hearing aids is presented. The circuit consists of a current-mode AGC（automatic gain control） and a current-mode adaptive filter.Compared with its conventional voltage-mode counterparts,the proposed front-end circuit has the identified features of frequency compensation based on the state space theory and continuous gain with an exponential characteristic.The frequency compensation which appears only in the DSP unit of the digital hearing aid can upgrade the performance of the analog hearing aid in the field of low-frequency hearing loss.The continuous gain should meet the requirement of any input amplitude level,while its exponential characteristic leads to a large input dynamic range in accordance with the dB SPL（sound pressure level）.Furthermore,the front-end circuit also provides a discrete knee point and discrete compression ratio to allow for high calibration flexibility.These features can accommodate users whose ears have different pain thresholds.Taking advantage of the current-mode technique,the MOS transistors work in the subthreshold region so that the quiescent current is small.Moreover,the input current can be compressed to a low voltage signal for processing according to the compression principle from the current-domain to the voltage-domain.Therefore,the objective of low voltage and low power（48μW at 1.4 V） can be easily achieved in a high threshold-voltage CMOS process of 0.35μm（V（TON） ＋ ｜V（TOP）｜≈1.35 V）.The THD is below -45 dB.The fabricated chip only occupies the area of 1×0.5 mm^2 and 1×1 mm^2.

Speech intelligibility and auditory perception of pre-school children with Hearing Aid,cochlear implant and Typical Hearing

Purpose:There is a growing interest in speech intelligibility and audito ry perception of deaf children.The aim of the present study was to compare speech intelligibility and auditory perception of pre-school children with Hearing Aid(HA),Cochlear Implant(Cl),and Typical Hearing(TH).Methods:The research design was descriptive-analytic and comparative.The participants comprised 75 male pre-school children aged 4-6 years in the 2017-2018 from Tehran,Iran.The participants were divided into three groups,and each group consisted of 25 children.The first and second groups were respectively selected from pre-school children with HA and CI using the convenience sampling method,while the third group was selected from pre-school children with TH by random sampling method.All children completed Speech Intelligibility Rating and Catego ries of Auditory Performance Questionnaires.Results:The findings indicated that the mean scores of speech intelligibility and auditory perception of the group with TH were significantly higher than those of the other groups(P<0.0001).The mean scores of speech intelligibility in the group with CI did not significantly differ from those of the group with HA(P<0.38).Also,the mean scores of auditory perception in the group with CI were significantly higher than those of the group with HA(P<0.002).Conclusion:The results showed that auditory perception in children with CI was significantly higher than children with HA.This finding highlights the importance of cochlear implantation at a younger age and its significant impact on auditory perception in deaf children.

Skin reactions caused by bone-anchored hearing aid(BAHA) implantation

Objective: To report a case of intractable skin reactions caused by bone-anchored hearing aid (BAHA) implantation to improve our under-standing and treatment of BAHA implantation-caused skin reactions. Methods:We reported a case of severe skin reactions caused by BAHA implantation. Related literature were also reviewed. Results:We found grade IV skin reactions, including hyperplasia around the implant, which led to the removal of the BAHA implant 10 months after implantation. The findings indicated poor skin hygiene, allergy to titanium and inadequate surgicals skills as the possible causes of the skin reaction. Conclusion: Skin adverse reactions, usually rare in BAHA implantation patients, may cause implant removal and implantation failure. We suggest to further investigate the mechanisms underlying titanium allergy. Copyright ? 2016, PLA General Hospital Department of Otolaryngology Head and Neck Surgery. Production and hosting by Elsevier (Singapore) Pte Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Hearing Aid

A man realized that he needed to purchase ahearing aid, but he was unwilling to spend muchmoney. "How much do they run?"he asked theclerk. "That depends," said. the salesman. "Theyrun from 2 to 2000."

Contemporary solutions for patients with microtia and congenital aural atresia-Hong Kong experience

Managing microtia patients is always a challenge. Multidisciplinary approach, good family support, well established doctorepatient relationship and well organised patient-support groups are the essential elements for success. With the advancement of implantable hearing devices,more options will be available for the microtia patients. Otologists play a leading role in the whole management process. They not only provide proper guidance to the patients in choosing the correct path of the treatment, but also play a key role in organising and maintaining a costeffective multidisciplinary rehabilitation team for the microtia patients.

Middle Ear Implants:Historical and futuristic perspective

Technological advancements are continuously changing the paradigm of human existence.Human beings are constantly engaging in various measures to reduce the extent of sensory and motor impairment.This has been in the form of various devices,e.g.orthopedic prosthesis,visual aids (spectacles) and hearing aids.Countless attempts throughout the centuries have been made in an effort to improve sound amplification in patients.This article seeks to highlights the technological journey of one such implant,the middle ear implant,from its inception to the more technological advanced futuristic proposals.While there are many amplification devices available presently,there still remains a group of patients who have not experienced adequate amplification for their hearing loss and this subset may gain the greatest benefit from middle ear implants.

A low-power high-performance configurable auto-gain control loop for a digital hearing aid SoC

A low-power, configurable auto-gain control loop for a digital hearing aid system on a chip （SoC） is presented. By adopting a mixed-signal feedback control structure and peak detection and judgment, it can work in automatic gain or variable gain control modes through a digital signal processing unit. A noise-reduction and dynamic range （DR） improvement technique is also used to ensure the DR of the circuit in a low-voltage supply. The circuit is implemented in an SMIC 0.13 μm 1P8M CMOS process. The measurement results show that in a I V power supply, 1.6 kHz input frequency and 200 mVp-p, the SFDR is 74.3 dB, the THD is 66.1 dB, and the total power is 89 μW, meeting the application requirements of hearing aid SoCs.

A current mode feed-forward gain control system for a 0.8 V CMOS hearing aid

A current mode feed-forward gain control（CMFGC）technique is presented,which is applied in the front-end system of a hearing aid chip.Compared with conventional automatic gain control（AGC）,CMFGC significantly improves the total harmonic distortion（THD）by digital gain control.To attain the digital gain control codes according to the extremely weak output signal from the microphone,a rectifier and a state controller implemented in current mode are proposed.A prototype chip has been designed based on a 0.13μm standard CMOS process.The measurement results show that the supply voltage can be as low as 0.6 V.And with the 0.8 V supply voltage,the THD is improved and below 0.06%（-64 dB）at the output level of 500 mV_（p-p）,yet the power consumption is limited to 40μW.In addition,the input referred noise is only 4μV_（rms）and the maximum gain is maintained at 33 dB.

A hearing aid on-chip system based on accuracy optimized front-and back-end blocks

A hearing aid on-chip system based on accuracy optimized front- and back-end blocks is presented for enhancing the signal processing accuracy of the hearing aid. Compared with the conventional system, the accuracy optimized system is characterized by the dual feedback network and the gain compensation technique used in the front-andback-endblocks,respectively,soastoalleviatethenonlinearitydistortioncausedbytheoutputswing.By usingthetechnique,theaccuracyofthewholehearingaidsystemcanbesignificantlyimproved.Theprototypechip has been designed with a 0.13 m standard CMOS process and tested with 1 V supply voltage. The measurement results show that, for driving a 16 loudspeaker with a normalized output level of 300 mV p-p, the total harmonic distortion reached about60 dB, achieving at least three times reduction compared to the previously reported works. In addition, the typical input referred noise is only about 5 υV rms.

Magnetic Implants Aid Hearing

The next generation of hearing aids may use tiny magnets that fit inside the ear. Researchersat a California company and an engineer at the University of Virginia are both developing systems that rely on magnets to convey sounds. Conventional hearing aids have three components:a microphone, an amplifier, and a speaker. The microphone picks up sounds and sends them to the am-

In-vivo fluorescence molecular tomography based on optimal small animal surface reconstruction

Accurate small animal surface reconstruction is important for full angle non-contact fluorescence molecular tomography （FMT） systems. In this letter, an optimal surface reconstruction method for FMT is proposed. The proposed method uses a line search method to minimize the mismatch between the reconstructed three- dimensional （3D） surface and the projected object silhouette at different angles. The results show that the mean mismatches of the 3D surfaces generated on three live anesthetized mice are all less than two charge coupled device （CCD） pixels （0.154 mm）. With the accurately reconstructed 3D surface, in-vivo FMT is also performed.