Analog Hearing Aids Research Articles

Comparison between the Satisfaction level of Digital and Analog hearing aid users

Hearing loss is the most common disability, affecting more than 250 million people in the world. Hearing aid helps to amplify the residual hearing.

MODEL BASED DESIGN FOR NOISE REMOVAL BY SPECTRAL SUBTRACTION FOR HEARING AID BY USING MATLAB & SIMULINK

This article deals with the removal of noise signal in the audio signal with the spectral subtraction of the noise and sub-band amplification for the improving the intelligibility of speech in signal for the hearing aid so that the person experiences the good quality of the speech signal over the analog hearing aid in the market

3D Games for Tuning and Learning About Hearing Aids

3D Games for Tuning and Learning About Hearing Aids

Aided Electrophysiology Using Direct Audio Input: Effects of Amplification and Absolute Signal Level.

This study investigated (a) the effect of amplification on cortical auditory evoked potentials (CAEPs) at different signal levels when signal-to-noise ratios (SNRs) were equated between unaided and aided conditions, and (b) the effect of absolute signal level on aided CAEPs when SNR was held constant. CAEPs were recorded from 13 young adults with normal hearing. A 1000-Hz pure tone was presented in unaided and aided conditions with a linear analog hearing aid. Direct audio input was used, allowing recorded hearing aid noise floor to be added to unaided conditions to equate SNRs between conditions. An additional stimulus was created through scaling the noise floor to study the effect of signal level. Amplification resulted in delayed N1 and P2 peak latencies relative to the unaided condition. An effect of absolute signal level (when SNR was constant) was present for aided CAEP area measures, such that larger area measures were found at higher levels. Results of this study further demonstrate that factors in addition to SNR must also be considered before CAEPs can be used to clinically to measure aided thresholds.

A programmable analog hearing aid system-on-chip with frequency compensation

An analog hearing aid with the function of frequency compensation is proposed and implemented considering the human factors. Introducing the current-mode technique, a filter designed by the state space methodology is integrated in the hearing aid to offer the function which only appears in the DSP unit of digital hearing aid. Combined with the filter embedded in the driver circuit adopting the minimum current selecting technique, the enhance frequency compensation can well match to the common low-frequency hearing loss with a stopband attenuation of 80 dB/dec. Moreover, a low-noise automatic gain control (AGC) is presented to improve the programmability with discreet gains, knee points and compression ratios. To enhance the comfortable level, the attack time and release time is set 20 and 100 ms with a peak detector. The input-referred noise is below 5 μVrms. The hearing aid can drive a 16 Ω receiver at the supply voltage of 1 V. The die area is 2.3 × 1.5 mm2 (AGC) and 0.93 × 0.86 mm2 (driver) in a 0.13 μm standard CMOS process and 1 × 1 mm2 (filter) in a 0.35 μm standard CMOS process.

Fragebogenassessments für die Hörgerätekontrolle

At the beginning of 2012 new fee schedule positions have been introduced to the ambulatory physician fee schedule ("Einheitlicher Bewertungsmaßstab", EBM) regarding the hearing aid fittings of youngsters and adults. With regards to quality assurance the use of a hearing aid outcome self-assessment inventory is made compulsive. This article aims to review available hearing aid (self-) assessment inventories as well as the evaluations regarding criteria for test quality implemented. For this systematic review a selective literature research in PubMed has been carried out. There are various self assessment inventories measuring hearing aid benefit. Many of the studies evaluating these inventories were implemented during the 1980ies and early 90ies when analogue hearing aids were commonly used. These results cannot automatically be transferred to the nowadays common digital devices. Only a small amount of studies investigated German translations of the mostly originally English inventories. In order to be able to identify the actual meaning of resulting values from these inventories, it is important for ENT doctors and audiologists to be well informed of the tests' quality criteria.

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 (48 μW at 1.4 V) can be easily achieved in a high threshold-voltage CMOS process of 0.35 μm (VTON + |VTOP|≈ 1.35 V). The THD is below −45 dB. The fabricated chip only occupies the area of 1 × 0.5 mm2 and 1 × 1 mm2.

Health Promotion in the Amazon Region

Health Promotion in the Amazon Region

Slow Cortical Potentials and Amplification—Part I: N1-P2 Measures

Slow cortical potentials (SCPs) are currently of great interest in the hearing aid fitting process for infants; however, there is conflicting evidence in the literature concerning the use of SCPs for this purpose. The current study investigated SCP amplitudes and latencies in young normal-hearing listeners in response to a 60 ms duration tonal stimulus (1000 Hz) presented at three intensities (30, 50, and 70 dB SPL) in aided and unaided conditions using three hearing aids (Analog, DigitalA, and DigitalB) with two gain settings (20 and 40 dB). Results showed that SCP amplitudes were smaller for the digital hearing aids compared with the analog hearing aid, and none of the hearing aids resulted in a reliable increase in response amplitude relative to the unaided across conditions. SCP latencies in analog conditions were not significantly different from latencies in the unaided conditions; however, both digital hearing aids resulted in significantly delayed SCP latencies. The results of the current study (as well as several previous studies) indicate that the SCP may not accurately reflect the amplified stimulus expected from the prescribed hearing aids. Thus, “aided-SCP” results must be interpreted with caution, and more research is required concerning possible clinical use of this technique.

State Budget Cuts Will Affect Members, Services

State Budget Cuts Will Affect Members, Services

Amplification for Music Lovers

Amplification for Music Lovers

Programming hearing instruments to make live music more enjoyable

Programming hearing instruments to make live music more enjoyable

Evaluation of the International Outcome Inventory for Hearing Aids in a Veteran Sample

The International Outcome Inventory for Hearing Aids (IOI-HA) was developed as a global hearing aid outcome measure targeting seven outcome domains. The published norms were based on a private-pay sample who were fitted with analog hearing aids. The purpose of this study was to evaluate the psychometric properties of the IOI-HA and to establish normative data in a veteran sample. Survey. The participants were 131 male veterans (mean age of 74.3 years, SD = 7.4) who were issued hearing aids with digital signal processing (DSP). Hearing aids with DSP that were fitted bilaterally between 2005 and 2007. Veterans were mailed two copies of the IOI-HA. The participants were instructed to complete the first copy of the questionnaire immediately and the second copy in two weeks. The completed questionnaires were mailed to the laboratory. The psychometric properties of the questionnaire were evaluated. As suggested by Cox and colleagues, the participants were divided into two categories based on their unaided subjective hearing difficulty. The two categories were (1) those with less hearing difficulty (none-to-moderate category) and (2) those who report more hearing difficulty (moderately severe+ category). The norms from the current veteran sample then were compared to the original, published sample. For each hearing difficulty category, the critical difference values were calculated for each item and for the total score. A factor analysis showed that the IOI-HA in the veteran sample had the identical subscale structure as reported in the original sample. For the total scale, the internal consistency was good (Chronbach's alpha = 0.83), and the test-retest reliability was high (lambda = 0.94). Group and individual norms were developed for both hearing difficulty categories in the veteran sample. For each IOI-HA item, the critical difference scores were < 1.0. This finding suggests that for any item on the IOI-HA, there is a 95 percent chance that an observed change of one response unit between two test sessions reflects a true change in outcome for a given domain. The results of this study confirmed that the psychometric properties of the IOI-HA questionnaire are strong and are essentially the same for the veteran sample and the original private-pay sample. The veteran norms, however, produced higher outcomes than those established originally, possibly because of differences in the population samples and/or hearing aid technology. Clinical and research applications of the current findings are presented. Based on the results from the current study, the norms established here should replace the original norms for use in veterans with current hearing aid technology.

Telefones celulares: influência nos sistemas auditivo e vestibular

Os sistemas de telecomunicações emitem radiofreqüência, uma radiação eletromagnética invisível. Telefones celulares transmitem microondas (450900 MHz no sistema analógico e 1,82,2 GHz no sistema digital), muito próximo à orelha do usuário. Esta energia é absorvida pela pele, orelha interna, nervo vestibulococlear e superfície do lobo temporal. OBJETIVO: Revisar a literatura sobre influência dos telefones celulares na audição e equilíbrio. FORMA DE ESTUDO: Revisão sistemática. METODOLOGIA: Foram pesquisados artigos nas bases Lilacs e Medline sobre a influência dos telefones celulares nos sistemas auditivo e vestibular, publicados de 2000 a 2005, e também materiais veiculados na Internet. RESULTADOS: Os estudos sobre radiação do telefone celular e risco de neurinoma do acústico apresentam resultados contraditórios. Alguns autores não encontram maior probabilidade de aparecimento do tumor nos usuários de celulares, enquanto outros relatam que a utilização de telefones analógicos por 10 anos ou mais aumenta o risco para o tumor. A exposição aguda às microondas emitidas pelo celular não influencia a atividade das células ciliadas externas da cóclea, in vivo e in vitro, a condução elétrica no nervo coclear, nem a fisiologia do sistema vestibular em humanos. As próteses auditivas analógicas são mais suscetíveis à interferência eletromagnética dos telefones celulares digitais. CONCLUSÃO: Não há comprovação de lesão cocleovestibular pelos telefones celulares.

Digital hearing aids: A brief history

The journey leading to the development of digital hearing aids began at Bell Laboratories in the mid 1960s when a digital computer was used to simulate an experimental high gain telephone with frequency shaping for people with hearing loss. The simulation was off-line at about 100 times real time. About 20 years later, a digital master hearing aid operating in real time was developed using a high speed array processor. The development of wearable digital hearing aids followed soon after as high speed digital signal processing (DSP) chips were developed. The first wearable digital hearing aid was a body worn instrument and was not a commercial success. At this stage, digitally controlled analog hearing aids could be made small enough to be worn on the ear and these instruments were widely used by the end of the decade. During the 1990s, low-power DSP chips were developed that were small enough to allow for all-digital ear-worn hearing aids to be developed. The challenge today is to tap the tremendous potential of digital signal processing techniques within the power and size constraints of a practical, wearable instrument.

Noise-management algorithm may improve speech intelligibility in noise

A likely consequence of sensorineural hearing loss is a diminished ability to understand speech in noisy backgrounds. Indeed, the inability to hear in noise is one of the main reasons for dissatisfaction with hearing aid use.1 Although hearing aids with a directional microphone provide substantial improvement in the ability of wearers to understand speech in noisy environments,2 space requirements and the uncertainty of directional characteristics when a directional hearing aid is inserted deeply into the ear canal prevent the implementation of such technology in the smallest completely-in-the-canal (CIC) hearing aids. A patient who insists on wearing CIC hearing aids will have to rely solely on the efficacy of single-mic noise-management strategies. Currently, most commercial “noise reduction” schemes use the modulation rates of the input signal as a basis for estimating the “speech” and “noise” nature of the input. “Speech” sounds are amplified with input-dependent gain, while “noise” sounds are typically amplified at a reduced gain level beyond input-dependent levels (see Chung, 20043). The exact amount of gain reduction and its time course vary greatly among manufacturers. Despite such differences, most studies have reported only an improvement in listening comfort by use of such a scheme.4 The improvement in listening comfort is noteworthy. It suggests that hearing-impaired persons whose hearing aids have noise reduction may be less affected by high-output sound pressure levels, less stressed, and less distracted in noisy situations, and may be more likely to attend to the sound sources and wear their hearing aids longer than if they lacked this feature. Wearers may also improve their participation in daily activities and their quality of life. It is possible that the reduction in stress level (or distractions) may improve the user’s speech understanding in some noisy environments.

Effects of Three Amplification Strategies on Speech Perception by Children With Severe and Profound Hearing Loss

Traditionally in the United Kingdom, children with severe and profound hearing loss have been fitted with linear, analog hearing aids. Fast-acting, wide-dynamic-range compression (WDRC) has been shown to give better discrimination of speech than linear amplification for moderately hearing-impaired young adults. For severe and profound hearing losses, higher compression ratios are needed. The resultant distortion of the temporal envelope and reduced modulation depth may offset improvements in audibility offered by WDRC. In this study, speech recognition and discrimination were assessed for severely and profoundly hearing-impaired children, using three different amplification strategies, including WDRC. Fifteen children (ages 7 to 15 yr) with severe and profound hearing loss were fitted bilaterally with high-power, multichannel compression hearing aids, incorporating one of three different amplification strategies: linear with peak clipping, linear with compression limiting, or WDRC. Output responses were matched to Desired Sensation Level (DSL i/o) targets. The children wore hearing aids programmed with each of the amplification strategies in turn, for at least 1 wk, in a counterbalanced order across children. After using a particular amplification strategy for at least 1 wk, speech perception tests were carried out. Speech scores on closed-set testing for the profound group showed significant benefit for WDRC over the other two algorithms. None of the other results showed a statistically significant effect of algorithm on speech performance. WDRC amplification sometimes led to better performance than linear amplification with peak clipping or output limiting, and it never led to poorer performance. Therefore, it appears to be safe to use well-designed WDRC for hearing-impaired children with severe or profound hearing loss.

Short- and Long-Term Outcomes of Adult Audiological Rehabilitation

To examine short- and long-term subjective benefits of providing a counseling-oriented audiological rehabilitation (AR) program as an adjunct to hearing aid intervention for individuals with adult-onset hearing loss. One hundred six veterans (68 men and 38 women), fit binaurally with digitally programmable analog hearing aids, participated. The Communication Profile for the Hearing Impaired (CPHI; ) was administered to all participants before hearing aid fitting. Half the patients were randomly assigned to receive hearing aids alone (i.e., control); the other patients were assigned to participate in a 4-wk group AR program in conjunction with receiving hearing aids (i.e., HA + AR). At the end of the AR program, the CPHI was again administered to all participants to assess short-term benefit and at 6 mo and 1 yr after hearing aid fitting to assess long-term benefit. A separate repeated-measures version of the general linear model was used to examine short- and long-term benefits for the CPHI factor scores (communication importance, communication performance, adjustment, interaction, and reaction) and for individual importance ratings and scale scores. Hearing aid use improved both short- and long-term self-perception of communication performance, with no additional benefits from participation in the AR program. Consistent with the goals of a counseling-oriented AR program, differential short-term treatment effects were found for communication strategy usage, which led to differential short-term benefits for the interaction and reaction factors. Although failing to reach strict criteria for statistical significance, there was an observable difference in short-term outcomes between the two groups for the adjustment factor, with greater improvements occurring for the HA + AR group. Over the course of the year, benefits measured for the HA + AR group remained stable, whereas scores for the control group continued to increase, resulting in no differences in factor scores between groups at 1 yr after intervention. The finding of a short-term differential treatment benefit for AR in terms of interaction and reaction, and possibly for adjustment, was important, as better outcomes in these areas may be important in the decision to keep hearing aids. If this is the case, then the data support the inclusion of a counseling-oriented AR program. Differential treatment effects in interaction and reaction appeared to result from communication strategy use, indicating that the AR program is meeting many of its goals in this area. The lack of long-term differential effects appeared as the result of continued changes in adjustment, interaction, and reaction with continued hearing aid experience.

Relative benefits of linear analogue and advanced digital hearing aids

Speech recognition performance and self-reported benefitfrom linear analogue and advanced (digital) hearing aidswere compared in 100 first-time hearing aid users withmild-to-moderate sensorineural hearing loss fitted monaurally with a behind-the-ear (BTE) hearing aid in a single-blind randomized crossover trial. Subjects usedeach aid for 5 weeks in turn, with aid order balancedacross subjects. Three alternative models of digital hearing aid were assigned to subjects according to a balanceddesign. Aid type was disguised to keep subjects blind within practical limitations. Aided speech recognition performance in noise was measured at speech levels of 65 and 75 dB at a speech-to-noise ratio (SNR) of _2 dB forclosed sets of single words. Self-rated benefit was measured using the Abbreviated Profile of Hearing Aid Benefit (APHAB) and the Glasgow Hearing Aid Benefit Profile (GHABP). Quality of life, hearing aid use and user preferences were also assessed. Speech recognition scores with the digital aids were significantly better at 75 dB than with the analogue aids. Self-reported benefit (APHAB, GHABP) and improvement in quality of life were generally not significantly different between analogue and digital aids, although aversiveness measured with the APHAB was significantly lower with digital aids,and satisfaction measured with the GHABP was greater. The digital aids were preferred significantly more often than the analogue aids, with 61 subjects choosing their digital aid, 26 choosing the analogue aid, and nine being equivocal. Overall, this study shows advantages for advanced digital over simple linear analogue aids interms of both objective and subjective outcomes, although average differences are not large.

Multiple-channel non-linear power hearing instruments for children with severe hearing impairment: long-term follow-up

The long-term benefits of multiple-channel non-linear technology for children with severe hearing impairment have yet to be fully investigated over the longer term. Twenty-one children with severe hearing loss participated in a study comparing performance on measures of audibility, speech understanding (in quiet and noise) and listening situations between the children's current analog hearing aids and a test hearing aid with multiple-channel non-linear compression (DigiFocus II Compact Power). Results were obtained from the children at 2 weeks, 8 weeks, 6 months and 12 months following the fitting of a multiple-channel non-linear hearing instrument. Compared with the children's own hearing instruments, the test instruments provided improved audibility, improvement in speech understanding in quiet and noise, and an improvement in listening skills. The gains in speech understanding were greater in noise than in quiet, suggesting that the test hearing instrument provided greatest improvement when listening to speech in noise. While performance increased over time, there was no statistically significant evidence to support continued acclimatization.