Low-frequency gain compensation in directional hearing aids

Hearing aids currently available on the market with both omnidirectional and directional microphone modes often have reduced amplification in the low frequencies when in directional microphone mode due to better phase matching. The effects of this low-frequency gain reduction for individuals with hearing loss in the low frequencies was of primary interest. Changes in sound quality for quiet listening environments following gain compensation in the low frequencies was of secondary interest. Thirty participants were fit with bilateral in-the-ear hearing aids, which were programmed in three ways while in directional microphone mode: no-gain compensation, adaptive-gain compensation, and full-gain compensation. All participants were tested with speech in noise tasks. Participants also made sound quality judgments based on monaural recordings made from the hearing aid. Results support a need for gain compensation for individuals with low-frequency hearing loss of greater than 40 dB HL.     

Bilateral amplification for the elderly: are two aids better than one?

This paper reviews the advantages and disadvantages of bilateral amplification as opposed to unilateral hearing use for older persons with bilateral symmetric hearing loss. Binaural advantages, such as improved localization and speech recognition in noise, are presented as they pertain to the older population. In addition, contraindications, such as binaural interference, increased costs, cosmetic concerns, decreased manipulation skills, and additional hearing aid management issues, are discussed. A case study is provided in which unilateral hearing aid fitting was more beneficial to a patient than two hearing aids. It is concluded that bilateral amplification should be attempted for all elderly patients with symmetric hearing loss, unless a contraindication is suspected.     

BAHA in children and adolescents with unilateral or bilateral conductive hearing loss: a study of outcome

OBJECTIVES: Bilateral BAHAs in adults with bilateral hearing loss (BHL) have proven to be superior to unilateral fitting, in both audiologically measurements and in overall patient satisfaction. There have been no similar studies in children. Furthermore, a recent meta-analysis of children with unilateral hearing loss (UHL) has shown numerous negative consequences. The objectives of the study were to investigate whether fitting of bilateral BAHAs in children with conductive BHL give additional hearing benefits, to investigate the effects of unilateral hearing aids in children with conductive UHL, and to identify different aspects of auditory problems in children with conductive UHL or BHL. STUDY DESIGN: This was a prospective study involving 22 children with either conductive UHL (unaided or with unilateral hearing aid) or conductive BHL (with unilateral or bilateral BAHAs) and 15 controls. METHODS: Baseline audiometry, tone thresholds in a sound field, speech recognition in noise and sound localization were tested without, and with unilateral and bilateral hearing aids. Two questionnaires, MAIS & MUSS and IOI-HA, were completed. RESULTS: Two problem areas were identified in the children with hearing impairment: in reactions to sounds and in intelligibility of speech. An additional BAHA in the children with BHL resulted in a tendency to have improved hearing in terms of better sound localization and speech recognition in noise. Fitting of unilateral hearing aids in the children with UHL gave some supplementary benefit in terms of better speech recognition in noise but no positive effect on ability to localize sound could be detected. Even so, all children fitted with hearing aids - either unilaterally or bilaterally - reported a positive outcome with their devices in the self-assessment questionnaire. CONCLUSIONS: Children with either UHL or BHL displayed several problems within the hearing domain. Fitting of bilateral BAHAs in children with BHL and of a single-sided hearing aid in children with UHL appears to have some supplementary audiological benefits and also renders high patient satisfaction. In order to investigate the possible supplementary effects of hearing aids, a 3-month trial of BAHA on Softband, either unilaterally or bilaterally, may be of value in children with conductive UHL or BHL, respectively.     

Comprehensive hearing aid assessment in adults with bilateral severe-profound sensorineural hearing loss who present for Cochlear implant evaluation

PurposeTo comprehensively assess and describe functional auditory performance in a group of adults with bilateral, moderate sloping to profound sensorineural hearing loss who were dissatisfied users of well-fit bilateral hearing aids and presented for Cochlear implant evaluation. Participants were evaluated with bilateral hearing aids and after six months of bimodal (Cochlear implant and a contralateral hearing aid) hearing experience with a Cochlear implant and contralateral hearing aid.MethodsStudy participants were assessed using pure tone audiometry, aided speech understanding in quiet (CNC words) and in noise (AzBio sentences at +10 and +5 dB SNR) in the sound field with unilateral and bilateral hearing aids fit to target. Participants completed subjective scales of quality of life, (Health Utilities Index Mark 3), hearing disability, (Speech, Spatial and Qualities of Hearing Scale) and a device use satisfaction scale. Participants ≥55 years were administered the Montreal Cognitive Assessment screening tool. One-hundred enrolled individuals completed baseline evaluations.ResultsAided bilateral mean speech understanding scores were 28% for CNC words and 31%, and 17% for AzBio sentences at a +10 dB, and +5 dB SNR, respectively. Mean scale ratings were 0.46 for overall quality of life and 3.19 for functional hearing ability. Ninety percent of participants reported dissatisfaction with overall hearing performance.ConclusionsEvaluation results, including functional performance metrics quantifying the deleterious effects of hearing loss for overall wellbeing, underscore that bilateral hearing aids are not an effective treatment for individuals with bilateral, moderate sloping to profound sensorineural hearing loss. Individuals with this degree of hearing impairment, who demonstrate poor aided speech understanding and dissatisfaction with hearing abilities in everyday life, require timely referral to a Cochlear implant clinic for further evaluation.     

言语、空间与听觉质量量表在老年听力损失者助听器验配中的应用

目的探讨言语、空间与听觉质量量表(speech,spatial and qualities of hearing scale,SSQ)用于老年听力损失患者佩戴助听器的效果评估作用。方法以100例老年感音神经性听力损失者(60~90岁)为研究对象,采用横断面研究和前瞻性研究,其中,无助听器使用经验者44例(75.8±8.1岁,气导纯音平均听阈59.8±13.3 dB HL)、有助听器使用经验者34例(77.5±6.3岁,气导纯音平均听阈64.5±17.8 dB HL,助听器佩戴时间大于三个月)进行横断面研究;22例(74.3±8.6岁,气导纯音平均听阈58.1±12.6 dB HL)首次配戴助听器者进行前瞻性研究;二组参与横断面研究者进行一次SSQ评估,前瞻性研究组分别在助听前和佩戴助听器1个月后进行二次SSQ评估,均采用面对面问答方式用SSQ量表评估三组受试者在言语理解能力、空间定位能力和声音聆听质量方面的变化。结果横断面研究结果显示,有助听经验组SSQ问卷言语理解(97.29±23.43分)、空间听觉(131.94±19.27分)、声音质量(143.53±20.31分)和总分(372.76±51.92分)均显著高于无助听经验组(分别为58.66±30.13、99.41±37.09、108.09±43.28、266.16±78.18分)。前瞻性研究结果显示,受试者初次佩戴助听器一个月后的SSQ问卷言语理解(106.27±13.86分)、空间听觉(136.00±14.09分)、声音质量(151.73±13.91分)和总分(394.00±34.70分)均显著高于佩戴助听器前(分别为65.64±21.89、115.09±17.17、111.91±25.41、292.64±45.58分),横断面研究和前瞻性研究结果均显示,老年听力损失患者佩戴助听器后在言语理解能力、空间声源定位能力和声音聆听质量方面均有显著改善(P<0.05)。结论SSQ量表可以有效评估老年听力损失患者助听器使用效果;老年听力损失患者佩戴助听器后在言语理解能力、空间定位能力和声音聆听质量方面均有显著提高。     

The effect of digital phase cancellation feedback reduction systems on amplified sound quality

The effect of feedback reduction (FBR) systems on sound quality recorded from two commercially available hearing aids was evaluated using paired comparison judgments by 16 participants with mild to severe sloping hearing loss. These comparisons were made with the FBR systems on and off without audible feedback and while attempting to control for differences in gain and clinical fitting factors. Wilcoxon signed rank test analyses showed that the participants were unable to differentiate between signals that had been recorded with the FBR systems on and off within the same hearing aid. However, significant between-instrument differences in sound quality were identified. The results support the activation of the FFT-phase cancellation FBR systems evaluated herein without concern for a noticeable degradation of sound quality.     

A multi-center,double blind clinical trial comparing benefit from three commonly used hearing aid circuits

OBJECTIVE: Although numerous studies have demonstrated that hearing aids provide significant benefit, carefully controlled, multi-center clinical trials have not been conducted. A multi-center clinical trial was conducted to compare the efficacy of three commonly used hearing aid circuits: peak clipping, compression limiting, and wide dynamic range compression. DESIGN: Patients (N = 360) with bilateral, sensorineural hearing loss were studied using a double blind, three-period, three-treatment crossover design. The patients were fit with each of three programmable hearing aid circuits. Outcome tests were administered in the unaided condition at baseline and then after 3 mo usage of each circuit, the tests were administered in both aided and unaided conditions. The outcome test battery included tests of speech recognition, sound quality and subjective scales of hearing aid benefit, including patients' overall rank-order rating of the three circuits. RESULTS: Each hearing aid circuit improved speech recognition markedly, with greater improvement observed for soft and conversationally loud speech in both quiet and noisy listening conditions. In addition, a significant reduction in the problems encountered in communication was observed. Some tests suggested that the two compression hearing aids provided a better listening experience than the peak clipping hearing aid. In the rank-order ratings, patients preferred the compression limiting hearing aid more frequently than the other two hearing aids. CONCLUSIONS: The three hearing aid circuits studied provide significant benefit both in quiet and in noisy listening situations. The two compression hearing aids appear to provide superior benefits compared to the linear circuit, although the differences between the hearing aids were smaller than the differences between unaided and aided conditions.     

Patient satisfaction with bilateral bone-anchored hearing aids: the Birmingham experience

The Birmingham bone-anchored hearing aid (BAHA) programme has fitted more than 300 patients with unilateral bone-anchored hearing aids since 1988. Some of the patients who benefited well with unilateral aids and who had used bilateral conventional aids previously applied for bilateral amplification. To date, 15 patients have been fitted with bilateral BAHAs. The benefits of bilateral amplification have been compared to unilateral amplification in 11 of these patients. Subjective analysis in the form of validated comprehensive questionnaires was undertaken. The Glasgow benefit inventory (GBI), which is a subjective patient orientated post-interventional questionnaire developed to evaluate any otorhinolaryngological surgery and therapy was administered. The results revealed that the use of bilateral bone-anchored hearing aids significantly enhanced general well being (patient benefit) and improved the patient's state of health (quality of life). The Chung and Stephens questionnaire which addresses specific issues related to binaural hearing was used. Our preliminary results are encouraging and are comparable to the experience of the Nijmegen BAHA group.     

Self-reported disability and handicap after hearing-aid fitting and benefit of hearing aids: comparison of fitting procedures, degree of hearing loss, experience with hearing aids and uni- and bilateral fittings

Self-reported outcome on hearing disability and handicap as well as overall health-related quality of life were measured after hearing-aid fitting in a large-scale clinical population. Fitting was performed according to two different procedures in a double-blind study design. We used a comparative procedure based on optimizing speech intelligibility scores and a strictly implemented fitting formula. Hearing disability and handicap were assessed with the hearing handicap and disability inventory and benefit of hearing aids with the abbreviated profile of hearing aid benefit. Effects on health-related quality of life and depression were assessed with the EuroQol-5D questionnaire and the geriatric depression scale. We found that hearing-aid fitting according to either procedure had a significantly positive effect on disability and handicap associated with hearing loss. This effect lasted for several months. Only the effect on disability persisted after 1-year of follow-up. Self-reported benefit from hearing aids was comparable for both fitting procedures. Unaided hearing disability was more pronounced in groups of participants with greater hearing loss, while the benefit of hearing aids was independent from the degree of hearing impairment. First-time hearing aid users reported greater benefit from their hearing aids. The added value from a bilateral hearing-aid fitting was not significant. Overall health-related quality of life and incidence of depression did not alter after hearing-aid fitting.     

Effect of Hearing Rehabilitation Therapy Program in Hearing Aid Users: A Prospective Randomized Controlled Study

ObjectivesDespite sufficient hearing gains, many patients with hearing loss have difficulty using hearing aids due to poor word recognition ability. This study was performed to introduce our hearing rehabilitation therapy (HRT) program for hearing aid users and to evaluate its effect on hearing improvement.MethodsIn this prospective randomized case-control study, 37 participants with moderate or moderate-severe sensorineural hearing loss who had used bilateral hearing aids for more than 3 months with sufficient functional hearing gain were enrolled in this study. Nineteen participants were randomly assigned to the control group (CG) and 18 patients were assigned to participate in our HRT program once a week for 8 consecutive weeks (hearing rehabilitation therapy group [HRTG]). Their hearing results and questionnaire scores for hearing handicap and hearing aid outcomes were prospectively collected and compared between the two groups.ResultsAfter completing 8 weeks of the HRT program, the HRTG showed a significantly greater improvement in scores for consonant-only and consonant-vowel sound perception than the CG (P<0.05). In addition, the HRTG showed a significant improvement in hearing ability as measured by two questionnaires (P<0.05), while no differences were observed in the CG. However, word and sentence recognition test results did not show significant differences between the two groups.ConclusionEven after short-term HRT, patients had subjectively better hearing outcomes and improved phoneme perception ability; this provides scientific evidence regarding a possible positive role for HRT programs in hearing aid users. Further validation in a larger population through a long-term follow-up study is needed.     

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

PurposeOur 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.MethodsOur 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.ResultsNo statistically significant differences were observed for speech-in-noise recognition, spectral-temporal 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).ConclusionOur 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 speech-in-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.     

Audiometric Results of Bilateral Bone-Anchored Hearing Aid Application in Patients With Bilateral Congenital Aural Atresia

The effect of bilateral application of bone-anchored hearing aids (BAHAs) was examined in terms of directional hearing and speech recognition in quiet and in noise in four patients with bilateral congenital atresia who, out of pure necessity, had been using a unilateral bone-conduction hearing aid since early life. This study comprised a prospective clinical evaluation in a single subject design; four patients with bilateral congenital atresia originating from the Nijmegen BAHA series participated. Three patients had Treacher Collins syndrome. All four patients had conductive, most probably, symmetrical, hearing loss. Recently these patients had applied for a second BAHA and were subsequently fitted bilaterally. With two BAHAs, all four patients showed significant improvement in sound localization. Also, speech perception in quiet showed significant improvement with bilateral application, and a significant improvement was found in speech perception in noise in three patients. These results suggest that patients with congenital conductive, symmetrical hearing loss will benefit from bilateral BAHAs.     

Bone‐anchored hearing aids for people with bilateral hearing impairment: a systematic review

Clin. Otolaryngol. 2011, 36 , 419–441 Background: Bone‐anchored hearing aids (BAHAs) are indicated for people with conductive or mixed hearing loss who can benefit from amplification of sound. In resource limited health care systems, it is important that evidence regarding the benefit of BAHAs is critically appraised to aid decision‐making. Objective of review: To assess the clinical effectiveness of BAHAs for people with bilateral hearing impairment. Type of review: Systematic review. Search strategy: Nineteen electronic resources were searched from inception to November 2009. Additional studies were sought from reference lists, clinical experts and BAHA manufacturers. Evaluation method: Inclusion criteria were applied by two reviewers independently. Data extraction and quality assessment of full papers were undertaken by one reviewer and checked by a second. Studies were synthesised through narrative review with tabulation of results. Results: Twelve studies were included. Studies suggested audiological benefits of BAHAs when compared with bone‐conduction hearing aids or no aiding. A mixed pattern of results was seen when BAHAs were compared to air‐conduction hearing aids. Improvements in quality of life with BAHAs were found by a hearing‐specific instrument but not generic quality of life measures. Issues such as improvement of discharging ears and length of time the aid can be worn were not adequately addressed by the studies. Studies demonstrated some benefits of bilateral BAHAs. Adverse events data were limited. The quality of the studies was low. Conclusions: The available evidence is weak. As such, caution is indicated in the interpretation of presently available data. However, based on the available evidence, BAHAs appear to be a reasonable treatment option for people with bilateral conductive or mixed hearing loss. Further research into the benefits of BAHAs, including quality of life, is required to reduce the uncertainty.     

Pilot study on the effectiveness of the conventional CROS, the transcranial CROS and the BAHA transcranial CROS in adults with unilateral inner ear deafness

The objective of the present pilot study is to evaluate the effectiveness of three conventional contralateral routing of sound (CROS) hearing aids in adults with unilateral inner ear deafness. The study included tertiary referral center. Ten patients with unilateral inner ear deafness and normal hearing in the contralateral ear were selected to evaluate three different methods of amplification: the CROS hearing aid, the completely in the canal hearing aid and the bone-anchored hearing aid CROS (BAHA). Each of the three hearing aids was tried in a random order for a period of 8 weeks. Audiometric performance, including speech-in-noise, directional hearing and subjective benefit were measured after each trial period, using the APHAB, SSQ and single-sided deafness questionnaire. Sound localization performance was essentially at chance level in all four conditions. Mixed results were seen on the other patient outcome measures that alternated in favor of one of the three CROS devices. After the trial, three patients chose to be fitted with the BAHA CROS and one with the conventional CROS. In conclusion, most of the patients experienced some degree of benefit with each of the three hearing aids. Preference for one of the three hearing aids was independent of the order in which they were tried. It would be worthwhile to formulate selection criteria; still, we recommend that all patients with unilateral inner ear deafness should be offered a trial with at least the BAHA CROS.     

Education qualification levels and school careers of unilateral versus bilateral hearing aid users

Objective: Analyse the difference in school careers and secondary school qualification levels between unilateral hearing aid users and bilateral hearing aid users. Study design: Retrospective questionnaire study. Setting: Postal‐based questionnaire. Participants: Names of adults known to have been fitted with unilateral or bilateral hearing aids during childhood were retrieved. This resulted in 292 names. Participants were selected using the following criteria: availability of the medical record, presence of bilateral hearing loss, completed secondary school education, normal IQ and a minimum aided word‐recognition score of 70% at 10 years of age. The questionnaire was sent to 50 potential participants of whom 40 responded, resulting in two groups comprising 19 unilateral and 21 bilateral hearing aid users. Methods: A questionnaire was developed to obtain data on secondary school levels and aspects of the school careers, such as type of schools attended (mainstream versus special), repeating a school year and additional assistance (speech and language therapy, personal frequency modulation systems). Main outcome measures: Comparison of the benefit of bilateral hearing aid fitting versus unilateral hearing aid fitting on secondary school qualification level, type of school the children attended, class failure and additional assistance used. Results: The group of bilaterally fitted hearing aid users eventually completed secondary school at a superior level than the unilaterally fitted users. 33% of binaural hearing aid users achieved qualifications giving access to a bachelors degree compared with 21% of unilateral users. There were no differences between those fitted with unilateral and bilateral hearing aids in the type of schools attended, repeating a school year and additional assistance. Conclusions: The bilateral hearing aid users obtained superior secondary school qualifications than the unilateral users but their school careers were comparable.     

Population study of the ability to benefit from amplification and the provision of a hearing aid in 55-74-year-old first-time hearing aid users

About 40% of 55-74-year-olds have an impairment in at least one ear of 25+ dB HL, and 27% have bilateral impairment at this level, with 11% being impaired bilaterally at 35+ dB HL. Only 6% currently use a hearing aid. The performance of a random sample of participants aged 55-74 years on speech-in-noise tasks shows that significant statistical benefit was obtained from bilateral amplification in over 20% of the population who do not currently use a hearing aid. The offer of a hearing aid to all those who exceeded a 25 dB HL criterion in the worse car was accepted and taken up by 40%, with 16% declining and the remainder being excluded for pathological and logistic reasons (e.g. hearing loss profile not suitable for aid). This is a very high rate of 71% acceptance. One in four fitted with the hearing aid showed a statistical advantage for hearing speech in noise in freefield (noise and speech from in front) with the hearing aid. Thus at least 10% of the population who do not currently use an aid would benefit substantially from a hearing aid in a quiet speech-in-noise environment. Those with poorer cognitive function show greater benefit overall and less disadvantage in very bad signal-to-noise environments. The overall pattern of results support screening and providing hearing aids to those who do not currently have an aid(s), and suggests that there would be considerable population benefit. At least two main questions for further research remain: (1) would bilateral aiding strategies give greater benefit; and (2) would different hearing aids and fitting strategies be more appropriate for people with differing 'cognitive task' loadings on phonological memory and lexical decision factors?     

Randomized trial of amplification strategies

BACKGROUND: Little is known about quality of life after the use of specific types of hearing aids, so it is difficult to determine whether technologies such as programmable circuits and directional microphones are worth the added expense. OBJECTIVE: To compare the effectiveness of an assistive listening device, a nonprogrammable nondirectional microphone hearing aid, with that of a programmable directional microphone hearing aid against the absence of amplification. DESIGN: Randomized controlled trial. SETTING: Audiology clinic at the VA Puget Sound Health Care System, Seattle, Wash. PATIENTS: Sixty veterans with bilateral moderate to severe sensorineural hearing loss completed the trial. Half the veterans (n = 30) had hearing loss that the Veterans Affairs clinic determined was rated as "service connected," which meant that they were eligible for Veterans Affairs-issued hearing aids. INTERVENTION: Veterans with non-service-connected hearing loss, who were ineligible for Veterans Affairs-issued hearing aids, were randomly assigned to no amplification (control arm) or to receive an assistive listening device. Veterans with service-connected loss were randomly assigned to receive either the nonprogrammable hearing aid that is routinely issued ("conventional") or a programmable aid with a directional microphone ("programmable"). MAIN OUTCOME MEASURES: Hearing-related quality of life, self-rated communication ability, adherence to use, and willingness to pay for the amplification devices (measured 3 months after fitting). RESULTS: Clear distinctions were observed between all 4 arms. The mean improvement in hearing-related quality of life (Hearing Handicap Inventory for the Elderly) scores was small for control patients (2.2 points) and patients who received an assistive listening device (4.4 points), excellent for patients who received a conventional device (17.4 points), and substantial for patients who received a programmable device (31.1 points) (P<.001 by the analysis of variance test). Qualitative analyses of free-text diary entries, self-reported communication ability (Abbreviated Profile of Hearing Aid Benefit) scores, adherence to hearing aid use, and willingness to pay for replacement devices showed similar trends. CONCLUSIONS: A programmable hearing aid with a directional microphone had the highest level of effectiveness in the veteran population. A nonprogrammable hearing aid with an omnidirectional microphone was also effective compared with an assistive listening device or no amplification.     

Language-specific strategy for programming hearing aids — A double-blind randomized controlled crossover study

Objective

Voice-aligned compression (VAC) is a method used in Oticon’s hearing aids to provide more comfortable hearing without sacrificing speech discrimination. The complex, non-linear compression curve for the VAC strategy is designed based on the frequency profile of certain spoken Western languages. We hypothesized that hearing aids could be further customized for Japanese-speaking users by modifying the compression curve using the frequency profile of spoken Japanese.