A systematic review of studies measuring and reporting hearing aid usage in older adults since 1999: a descriptive summary of measurement tools

Objective

A systematic review was conducted to identify and quality assess how studies published since 1999 have measured and reported the usage of hearing aids in older adults. The relationship between usage and other dimensions of hearing aid outcome, age and hearing loss are summarised.

Data sources

Articles were identified through systematic searches in PubMed/MEDLINE, The University of Nottingham Online Catalogue, Web of Science and through reference checking. Study eligibility criteria: (1) participants aged fifty years or over with sensori-neural hearing loss, (2) provision of an air conduction hearing aid, (3) inclusion of hearing aid usage measure(s) and (4) published between 1999 and 2011.

Results

Of the initial 1933 papers obtained from the searches, a total of 64 were found eligible for review and were quality assessed on six dimensions: study design, choice of outcome instruments, level of reporting (usage, age, and audiometry) and cross validation of usage measures. Five papers were rated as being of high quality (scoring 10–12), 35 papers were rated as being of moderate quality (scoring 7–9), 22 as low quality (scoring 4–6) and two as very low quality (scoring 0–2). Fifteen different methods were identified for assessing the usage of hearing aids.

Conclusions

Generally, the usage data reviewed was not well specified. There was a lack of consistency and robustness in the way that usage of hearing aids was assessed and categorised. There is a need for more standardised level of reporting of hearing aid usage data to further understand the relationship between usage and hearing aid outcomes.     

Hearing Loss and Cognition: The Role of Hearing Aids,Social Isolation and Depression

Hearing loss is associated with poor cognitive performance and incident dementia and may contribute to cognitive decline. Treating hearing loss with hearing aids may ameliorate cognitive decline. The purpose of this study was to test whether use of hearing aids was associated with better cognitive performance, and if this relationship was mediated via social isolation and/or depression. Structural equation modelling of associations between hearing loss, cognitive performance, social isolation, depression and hearing aid use was carried out with a subsample of the UK Biobank data set (n = 164,770) of UK adults aged 40 to 69 years who completed a hearing test. Age, sex, general health and socioeconomic status were controlled for as potential confounders. Hearing aid use was associated with better cognition, independently of social isolation and depression. This finding was consistent with the hypothesis that hearing aids may improve cognitive performance, although if hearing aids do have a positive effect on cognition it is not likely to be via reduction of the adverse effects of hearing loss on social isolation or depression. We suggest that any positive effects of hearing aid use on cognition may be via improvement in audibility or associated increases in self-efficacy. Alternatively, positive associations between hearing aid use and cognition may be accounted for by more cognitively able people seeking and using hearing aids. Further research is required to determine the direction of association, if there is any direct causal relationship between hearing aid use and better cognition, and whether hearing aid use results in reduction in rates of cognitive decline measured longitudinally.     

Provision of hearing aids: does specialist assessment cause delay?

OBJECTIVE--To identify the main delay in the provision of hearing aids for people with impaired hearing and identify possible problems and short-comings caused by a community based hearing aid dispensing service. DESIGN--Prospective cohort analysis based on data collected from patients on the duration of hearing impairment, from the referral letters in respect of the general practitioners'' findings on otoscopy, and from the ear, nose, and throat assessment in the clinic with respect to the outcome of specialist otoscopy and management of the hearing impairment. SETTING--General ear, nose, and throat outpatient clinic. PATIENTS--100 Consecutive patients aged 19-94 referred by general practitioners for the provision of hearing aids or for assessment and treatment of impaired hearing. RESULTS--Most patients with impaired hearing did not seek medical advice for at least a year. The time from referral by the general practitioner to the provision of a hearing aid was under two months. General practitioners consistently recognised normality on otoscopy but failed to recognise abnormality in eight of 45 cases. Seven patients required further investigation to exclude serious disease and nine had conditions amenable to surgery. CONCLUSIONS--The main cause of delay in treating impaired hearing is failure by patients to seek help promptly. Specialist assessment of patients with impaired hearing is preferable and does not necessarily cause delay in providing hearing aids. The provision of hearing aids should remain a hospital based service.     

Impact of CDMA wireless phone power output and puncture rate on hearing aid interference levels

Interference between digital wireless phones and hearing aids occurs when the radiofrequency bursts from the phone transmission are demodulated by the hearing aid amplifier. The amplified interference signal is heard as a "buzz" or "static" by the hearing aid wearer. Most research and standards development activity has focused on worst-case scenarios with the phone operating at its maximum power. Since this power level is often not typical in urban and suburban settings, it is of value to determine the impact of lower power levels on the overall level of audible interference. Using a frequency analyzer, and several hearings aids and code division multiple access (CDMA) phones, the audio frequency spectrum of interference was recorded for each phone-aid combination and for a range of power levels producing from no interference to maximum interference. As phone power is increased, the interference signal becomes distinguishable from the ambient noise level and a linear response region is observed in which a specified increase in power output results in a proportional increase in the overall input referenced interference level (OIRIL). As power is increased beyond the linear region, the hearing aid enters a saturation region where an additional power increase results in a reduction or no increase in the OIRIL. The numeric differences in interference documented in this study were used in conjunction with the results of a previous study by the authors to determine the impact of reduced power on speech intelligibility and annoyance. The amount of improvement for a given power reduction depends on the radiofrequency immunity of the hearing aid and is substantial for hearing aids with poor immunity. For high-immunity aids, the level of audible interference remains low even at high phone power levels.     

Hearing disability in people aged 50-65: effectiveness and acceptability of rehabilitative intervention.

OBJECTIVE--To determine the best means of detecting hearing disability in subjects aged 50-65 and whether rehabilitative intervention is acceptable in this age group. DESIGN--Questionnaire survey of patients on general practice age-sex registers. Two types of questionnaire were used, one being based on the closed set approach of the Institute of Hearing Research questionnaire, which had been used in a pilot study, and the other being a simplified version of this questionnaire developed by the Welsh Hearing Institute and based on open set questions. Questionnaires were sent up to three times, and any patients who had not responded two months after the last posting were personally contacted. SETTING--Two general practices in Glyncorrwg and Blaengwynfi in the Afan valley, West Glamorgan. PATIENTS--271 Patients in Glyncorrwg (136 men, 135 women) and 333 patients in Blaengwynfi (173 men, 160 women) aged 50-65. INTERVENTIONS--All patients indicating hearing disability in answering the questionnaires were invited to attend for a evaluative session in their village. After audiometric testing advice and arrangements for fitting a hearing aid were offered as appropriate. MAIN OUTCOME MEASURES--Response rates and prevalence of hearing disability before intervention and of possession of hearing aids before and after intervention. RESULTS--After three postings and personal contact the response rate was 98% (266/271) in Glyncorrwg, where the complex questionnaire was used, and 97% (322/333) in Blaengwynfi. The prevalence of hearing disability was respectively 53% (141/266) and 46% (148/322) and the prevalence of owning a hearing aid 7% (19/266) and 8% (24/322). After intervention the possession of hearing aids rose to 24% (64/266) in Glyncorrwg and 22% (71/322) in Blaengwynfi; six months later the aids were being used regularly. A direct comparison of the two questionnaires in 69 subjects from Blaengwynfi showed no significant differences in the amount of disability detected by each one. The first posting of questionnaires detected 65% (189/289) of the hearing disability in the two villages or 78% (72/92) of those prepared to accept hearing aids for the first time; 96% (88/92) of those who accepted hearing aids were detected by two postings. CONCLUSIONS--Simple questionnaires are effective in detecting hearing disabilities in people aged 50-65, and intervention was acceptable in many of those who reported having difficulties in hearing. The response rates from successive postings suggest that two postings are sufficient in terms of the return in detecting those who will accept intervention.     

Limitations of bandwidth compression hearing aids applied to the voiced portion of speech

Numerous speech processing techniques have been applied to assist hearing-impaired subjects with extreme high-frequency hearing losses who can be helped only to a limited degree with conventional hearing aids. The results of providing this class of deaf subjects with a speech encoding hearing aid, which is able to reproduce intelligible speech for their particular needs, have generally been disappointing. There are at least four problems related to bandwidth compression applied to the voiced portion of speech: (1) the problem of pitch extraction in real time; (2) pitch extraction under realistic listening conditions, i.e. when competing speech and noise sources are present; (3) an insufficient data base for successful compression of voiced speech; and (4) the introduction of undesirable spectral energies in the bandwidth-compressed signal, due to the compression process itself. Experiments seem to indicate that voiced speech segments bandwidth limited to f = 1000 Hz, even at a loss of higher formant frequencies, is in most instances superior in intelligibility compared to bandwidth-compressed voiced speech segments of the same bandwidth, even if pitch can be extracted with no error. With the added complexity of real-time pitch extraction which has to function in actual listening conditions, it is doubtful that a speech encoding hearing aid, based on bandwidth compression on the voiced portion of speech, could be successfully implemented. However, if bandwidth compression is applied to the unvoiced portions of speech only, the above limitations can be overcome (1).     

A technical comparison of digital frequency-lowering algorithms available in two current hearing aids

Background

Recently two major manufacturers of hearing aids introduced two distinct frequency-lowering techniques that were designed to compensate in part for the perceptual effects of high-frequency hearing impairments. The Widex “Audibility Extender” is a linear frequency transposition scheme, whereas the Phonak “SoundRecover” scheme employs nonlinear frequency compression. Although these schemes process sound signals in very different ways, studies investigating their use by both adults and children with hearing impairment have reported significant perceptual benefits. However, the modifications that these innovative schemes apply to sound signals have not previously been described or compared in detail.

Methods

The main aim of the present study was to analyze these schemes''technical performance by measuring outputs from each type of hearing aid with the frequency-lowering functions enabled and disabled. The input signals included sinusoids, flute sounds, and speech material. Spectral analyses were carried out on the output signals produced by the hearing aids in each condition.

Conclusions

The results of the analyses confirmed that each scheme was effective at lowering certain high-frequency acoustic signals, although both techniques also distorted some signals. Most importantly, the application of either frequency-lowering scheme would be expected to improve the audibility of many sounds having salient high-frequency components. Nevertheless, considerably different perceptual effects would be expected from these schemes, even when each hearing aid is fitted in accordance with the same audiometric configuration of hearing impairment. In general, these findings reinforce the need for appropriate selection and fitting of sound-processing schemes in modern hearing aids to suit the characteristics and preferences of individual listeners.     

A body-worn Delayed Auditory Feedback Fluency Aid for stammerers

Body-worn fluency aids, aiming to relieve the disability of stammering during periods of use (just as spectales correct defective vision only while worn, and make no claim to treat or cure the disability) have been envisaged for a quarter of a century. Most have been based on Auditory Feedback Masking, but the Aid described here is probably the first body-worn version to be based on the principle of Delayed Auditory Feedback, recognised for 20 years as an aid to fluency, but hitherto available only in desk-top equipment. The embodiment described here fits easily into a breast pocket and is wired to a tie-pin microphone and two standard hearing aid earpieces. Voice actuated switching enables other speakers to be heard clearly and undelayed. Results of early clinical trials are indicated.     

Evaluation method for hearing aid fitting under reverberation: comparison between monaural and binaural hearing aids

Some hearing-impaired persons with hearing aids complain of listening difficulty under reverberation. No method, however, is currently available for hearing aid fitting that permits evaluation of hearing difficulty caused by reverberations. In this study, we produced speech materials with a reverberation time of 2.02 s that mimicked a reverberant environment (a classroom). Speech materials with reverberation times of 0 and 1.01 s were also made. Listening tests were performed with these materials in hearing-impaired subjects and normal-hearing subjects in a soundproof booth. Listening tests were also done in a classroom. Our results showed that speech material with a reverberation time of 2.02 s had a decreased listening-test score in hearing-impaired subjects with both monaural and binaural hearing aids. Similar results were obtained in a reverberant environment. Our findings suggest the validity of using speech materials with different reverberation times to predict the listening performance under reverberation of hearing-impaired persons with hearing aids.     

External memory aids for patients with dementia: a literature study on efficacy and applicability

Memory problems are the most common cognitive deficits in dementia. In order to help these patients with their everyday activities and to increase their quality of life, a number of memory aids have been developed. This paper focuses on the efficacy and the applicability of three different types of external memory aids. The findings suggest that environmental adjustment is an easy and low-priced method. It is beneficial even for patients in the most severe stages of dementia, since only a limited amount of training is necessary. The non-electronic aids are also relatively cheap and easy to learn. The electronic aids are more expensive and, at this point, only a few studies have investigated the efficacy of this memory aid on the memory problems of patients with dementia. However, most published studies only investigated small samples. Hence, the current results should be interpreted with caution.     

Restoring hearing with active hearing implants.

Due to shortcomings of conventional hearing aid technology, such as unsatisfactory sound quality due to limited frequency range and undesired distortion, occlusion of the outer ear canal, and acoustic feedback with high amplification, but also psychological aspects of stigmatization, a significant of patients in need of hearing aids are actually not wearing them. Active hearing implants can be distinguished in: (1) impedance transformation implants (ITI), (2) cochlear amplifier implants (CAI), (3) cochlear implants (CI), and (4) brain stem implants (BSI). Whereas ITI are designed for patients with middle ear hearing loss, CAI are intended to restore hearing in patients with inner ear hearing loss. Advantages of CAI may be: (1) improved sound fidelity, (2) no occlusion of the outer ear canal, (3) no feedback, and (4) invisibility. However, not all features are true for every device. CI replace inner ear function in deaf or almost deaf patients. This article gives an overview on the range of active hearing implants to restore hearing and outlines the future use of computer and robot aided surgery.     

Predicting the Perceived Sound Quality of Frequency-Compressed Speech

The performance of objective speech and audio quality measures for the prediction of the perceived quality of frequency-compressed speech in hearing aids is investigated in this paper. A number of existing quality measures have been applied to speech signals processed by a hearing aid, which compresses speech spectra along frequency in order to make information contained in higher frequencies audible for listeners with severe high-frequency hearing loss. Quality measures were compared with subjective ratings obtained from normal hearing and hearing impaired children and adults in an earlier study. High correlations were achieved with quality measures computed by quality models that are based on the auditory model of Dau et al., namely, the measure PSM, computed by the quality model PEMO-Q; the measure qc, computed by the quality model proposed by Hansen and Kollmeier; and the linear subcomponent of the HASQI. For the prediction of quality ratings by hearing impaired listeners, extensions of some models incorporating hearing loss were implemented and shown to achieve improved prediction accuracy. Results indicate that these objective quality measures can potentially serve as tools for assisting in initial setting of frequency compression parameters.     

Neurodynamic evaluation of hearing aid features using EEG correlates of listening effort

In this study, we propose a novel estimate of listening effort using electroencephalographic data. This method is a translation of our past findings, gained from the evoked electroencephalographic activity, to the oscillatory EEG activity. To test this technique, electroencephalographic data from experienced hearing aid users with moderate hearing loss were recorded, wearing hearing aids. The investigated hearing aid settings were: a directional microphone combined with a noise reduction algorithm in a medium and a strong setting, the noise reduction setting turned off, and a setting using omnidirectional microphones without any noise reduction. The results suggest that the electroencephalographic estimate of listening effort seems to be a useful tool to map the exerted effort of the participants. In addition, the results indicate that a directional processing mode can reduce the listening effort in multitalker listening situations.     

Molecular genetics of usher syndrome

Usher syndrome (USH) is inherited in an autosomal recessive mode. The disease is characterized by hearing loss, progressing vision loss, and vestibular dysfunction. In most cases, it is the reason for deafness and blindness in school-age children. The prevalence of USH in the main population is estimated as 4.4 per 100000 individuals, approximately. The prevalence of heterozygous carriers can reach 1 per 70 normally hearing individuals. There is currently no effective treatment of USH. The patients are provided with hearing aids, but, in case of severe hearing impairement these aids give no effect. In view of this, developing diagnostic methods is important. It is believed that molecular genetic investigations will enable early diagnostics of the syndrome.     

Health insurance coverage of mothers and children (1974).

One aspect of establishing effective communication between physicians and patients has not received adequate attention: the special needs and challenges presented by patients with impaired hearing. In this article the term “hearing impaired” is generic and is applied to both those persons who are commonly labeled “deaf” and those labeled “hard of hearing” as a result of a bilateral hearing loss. The general skills, both verbal and nonverbal, that a physician must have in order to communicate successfully with a hearing-impaired patient are in essence the same as those required for a hearing patient. Where the divergence occurs is not in the basic skills (empathy, probing and the like) but rather in the means of applying them. Communicating with a hearing-impaired patient makes the use of some combination of the following necessary: speech, hearing, speechreading (lipreading), writing, visual aids, visual language systems and the assistance of an interpreter.     

Aids and adaptations for the elderly at home: underprovided,underused, and undermaintained

A random sample of 140 elderly people aged over 75 was selected from the age-sex register of an urban general practice to assess the provision and use of aids and adaptations in their homes. Many of the aids that the elderly had were faulty, including half of the walking aids and 15% of hearing aids, reading spectacles, and dentures, and up to half of the aids were not used. Yet despite this underuse there were many disabled elderly people who required aids for the bath and toilet.When screening of elderly people is carried out in general practice assessment of aids and adaptations should be included to see that they are provided where needed, are used, and are adequately maintained.     

The effect of visual cues on difficulty ratings for segregation of musical streams in listeners with impaired hearing

Background

Enjoyment of music is an important part of life that may be degraded for people with hearing impairments, especially those using cochlear implants. The ability to follow separate lines of melody is an important factor in music appreciation. This ability relies on effective auditory streaming, which is much reduced in people with hearing impairment, contributing to difficulties in music appreciation. The aim of this study was to assess whether visual cues could reduce the subjective difficulty of segregating a melody from interleaved background notes in normally hearing listeners, those using hearing aids, and those using cochlear implants.

Methodology/Principal Findings

Normally hearing listeners (N = 20), hearing aid users (N = 10), and cochlear implant users (N = 11) were asked to rate the difficulty of segregating a repeating four-note melody from random interleaved distracter notes. The pitch of the background notes was gradually increased or decreased throughout blocks, providing a range of difficulty from easy (with a large pitch separation between melody and distracter) to impossible (with the melody and distracter completely overlapping). Visual cues were provided on half the blocks, and difficulty ratings for blocks with and without visual cues were compared between groups. Visual cues reduced the subjective difficulty of extracting the melody from the distracter notes for normally hearing listeners and cochlear implant users, but not hearing aid users.

Conclusion/Significance

Simple visual cues may improve the ability of cochlear implant users to segregate lines of music, thus potentially increasing their enjoyment of music. More research is needed to determine what type of acoustic cues to encode visually in order to optimise the benefits they may provide.     

Communication aids in patients with motor neurone disease.

The study aimed at determining the main factors responsible for the speech and communication problems in motor neurone disease to try to assess the suitability of commercially available aids. Sixteen patients suffering from motor neurone disease with communication problems had their speech assessed by using the Frenchay dysarthria assessment. It was found essential to offer a choice of aids to the patient since suitability of a particular aid could not be evaluated without the patient practising with it.     

Free field pure tone audiometry as a comparative system for the assessment and fitting of hearing aids

In this brief report it is shown that without the use of language and/or complex tones, it has been possible to determine whether or not the potential of residual hearing is being fully utilized by the hearing impaired child or adult with or without an aid. Furthermore, because the system is one of direct and immediate comparison it can be used to confirm if the initial selection of a specific hearing prosthesis is potentially correct.