Types Of Hearing Aids Research Articles

Smart Technology for Aging, Disability, and Independence: The State of the Science.

We live in a technological world with a rapidly ageing population. With age, increases are seen in cognitive impairment, motor/movement impairment, and hearing and visual impairment, leading to an increased likelihood of hospitalization for older adults. Considering the rapid growth both of North America's ageing population and of technology, it makes good sense to develop and apply smart technology to help older adults maintain or improve their heath and quality of life. William Mann's Smart Technology for Aging, Disability, and Independence: The State of the Science is a timely and informative book for researchers, clinicians, and students in rehabilitation, medicine, or engineering, as well as for people who have elderly family members and friends. The first chapter provides detailed information about older adults, disability, and technology as well as clear definitions of key terms used throughout the book. Relevant socio-demographic data and trends of ageing, disability, and technology are presented in a very accessible format for readers. What this book does especially well is to introduce and explain smart technology to help older adults with disabilities in a practical way, making it easy for readers to apply the information to their own particular field or need. The technology discussed in the book ranges from the very basic—such as walking aids, canes, and hearing aids—to the very advanced, including robots and smart houses. Some readers may find the more advanced technology a bit difficult to understand, and this information may be less relevant for older adults with limited financial means. In Chapter 4, the health conditions most common among older adults are categorized (e.g., vision, cognition, and mobility/movement problems). Assistive devices applicable to each category are listed and described, including (1) electronic reading devices for older adults with visual impairment; (2) different types of hearing aids for elderly persons with hearing impairment; and (3) wheelchairs and other self-care devices for older individuals with mobility/movement impairment. Information about the use of each device is provided, as well as pictures, descriptions, costs, and technical details. Some chapters introduce the technology or device information in an easy to read and compare tabular format, enabling readers without previous technical training to read and enjoy the book. Chapter 10 presents common causes of older adults’ injury and death (e.g., falls, fire, or medication errors). Both low- and high-technology devices that can prevent older adults from injury or death are then described. Detailed information as to how smart technology can help older adults maintain their health and quality of life is provided throughout the book. Overall, this book introduces technology for older adults with disabilities in a user-friendly way and leaves readers feeling comfortable with these new developments. Technology will likely be an important part of our future, one that can make older adults’ daily lives easier, safer, and more comfortable. This is a wonderful book, especially for clinicians, researchers, and students in rehabilitation, medicine, or engineering, to update current knowledge or acquire new information about smart technology applicable to older adults with disabilities. I am certain that it will inspire these types of readers and provide them with great ideas for their research or clinical programs for older adults.

Comparison of speech intelligibility in quiet and in noise after hearing aid fitting according to a purely prescriptive and a comparative fitting procedure

We compared two different types of hearing-aid fitting procedures in a double-blind randomized clinical study. Hearing aid fittings based on a purely prescriptive procedure (the NAL-RP formula) were compared to a comparative fitting procedure based on optimizing speech intelligibility scores. Main outcome measures were improvement of speech intelligibility scores in quiet and in noise. Data were related to the real-ear insertion responses that were measured after fitting. For analysis purposes subgroups were composed according to degree of hearing loss, characterized by unaided speech intelligibility in quiet, previous experience with hearing aids, unilateral or bilateral fittings and type of hearing aid. We found equal improvement of speech intelligibility in quiet, while fitting according to the prescriptive formula resulted in a somewhat better performance as expressed by the speech-to-noise ratio in comparison to the comparative procedure. Both procedures resulted in comparable real-ear insertion responses.

The Value of Routine Real Ear Measurement of the Gain of Digital Hearing Aids

The main aims of this study were: (1) to determine whether routine real ear insertion gain (REIG) measurement is necessary in fitting digital hearing aids; and (2) to assess the extent to which modifying the frequency-gain response of an aid can lead to better matches to the target in cases where the target gain was not initially achieved. The target formula was selected as NAL-NL1 in the programming software of four types of digital hearing aids. REIG measurements on 42 ears showed that 64% of cases failed to come within +/-10 dB of the target at one or more of the following frequencies: 0.25, 0.5, 0.75, 1, 1.5, 2, and 4 kHz. After adjusting the frequency-gain response of the aids, based on the REIG results, 83% of cases came within +/-10 dB of the target. The target was met more often, both before and after adjustment, for aids with seven gain "handles" than for aids with four gain "handles". The results indicate that REIG measurements can and should be used to achieve more accurate fittings but that accurate adjustments are difficult with some aids.

Updated surgical experience with bone-anchored hearing aids in children

We present the results of a retrospective review of children undergoing implantation with bone-anchored hearing aids (BAHAs) at the Great Ormond Street Hospital for Children. The case notes of 71 children undergoing BAHA placement at the Great Ormond Street Hospital for Children between December 1990 and August 2002 were reviewed. Outcome measures included hearing thresholds, incidence of fixture loss, skin reaction and need for revision. Quality of life outcomes were also measured. Eighty-five ears had been implanted. Fifty-four per cent of children had experienced no complications, 42 per cent had required revision surgery and 26 per cent had experienced fixture loss at some point. Young age at implantation was associated with an adverse outcome. Trauma and failure of osseointegration had been the commonest reasons for failure. A skin reaction around the abutment had occurred at some point in 37 per cent of children but had persisted for longer than six months in only 9 per cent; this had been associated with fixture loss. The use of fixture site split skin grafts had reduced problems with skin hypertrophy and hair overgrowth. Hearing thresholds when using BAHAs had been comparable to those when using bone conduction hearing aids. However, BAHAs had significant additional benefits in terms of sound quality, ease of use and overall quality of life. Bone-anchored hearing aids provide significant benefits over other types of hearing aid, both audiologically and in terms of quality of life. Careful selection of candidates and meticulous follow up are required in order to minimize complications.

Multi-coil coupling system for hearing aid applications

A hearing improvement device using a multi-coil coupling system and methods for operating such a device are disclosed. An embodiment of the present invention may use an array microphone to provide highly directional reception. The received audio signal may be filtered, amplified, and converted into a magnetic field for coupling to the telecoil in a conventional hearing aid. Multiple transmit inductors may be used to effectively couple to both in-the-ear and behind-the-ear type hearing aids, and an additional embodiment is disclosed which may be used with an earphone, for users not requiring a hearing aid.

La obtención de medidas en oído real mediante sonda microfónica. Consideraciones prácticas

Las medidas con sonda microfónica aportan un método eficiente y eficaz en la verificación final de la adaptación audioprotésica toda vez que permiten estudiar la respuesta electroacústica con el molde adaptado y el audífono en funcionamiento en oído real. El uso de estas medidas tiene en cuenta las diferencias individuales de cada paciente y las peculiaridades de un audífono y molde auditivo en particular. Este tipo de medidas electroacústicas pueden ser llevadas acabo en todo tipo de prótesis auditivas incluidas las digitales. En este artículo se revisan de forma práctica los procedimientos al uso en la clínica para la obtención de medidas de respuesta del audífono en oído real mediante sonda microfónica.

Syntactic Movement in Orally Trained Children With Hearing Impairment

This study explored the comprehension and production of sentences derived by syntactic movement, in orally trained school-age Hebrew-speaking children with moderate to profound hearing impairment, aged 7;8-9;9 years. Experiments 1 and 2 tested the comprehension of relative clauses and topicalization sentences (with word orders of OVS [object, verb, subject] and OSV [object, subject, verb]) using a sentence-picture matching task. Experiments 3 and 4 tested the production of relative clauses using two elicitation tasks. Experiment 5 tested the comprehension of relative clauses with and without resumptive pronouns. As a group, the children with hearing loss failed to understand object relatives and OVS topicalization sentences. In the production tasks they either avoided producing a sentence with syntactic movement, by using a relative clauses with a resumptive pronoun instead of a gap or by producing a sentence without a relative clause, or produced ungrammatical sentences. They understood correctly object relatives with resumptive pronouns, which are not derived by movement. Both comprehension and production of the hearing-impaired group was significantly different from that of the hearing control group. Individual performance was strongly correlated with the age of intervention: only children who received hearing aids before the age of 8 months performed well in the comprehension tasks. Type of hearing aid, duration of use of a cochlear implant, and degree of hearing loss did not correlate with syntactic comprehension.

Storing batteries in airtight tube found to prolong battery life

Batteries have been essential to the operation of hearing aids since they were first produced in the late 1800s and early 1900s. Vacuum tube hearing aids required two batteries, while carbon hearing aids needed one or more batteries in series, and the user had to wear a separate battery pack. The zinc-oxide batteries used in these devices were expensive and needed to be stored in a cool place to prolong their life. This type of battery discharged at a constant rate, requiring that the user continually turn up the hearing aid's volume as the battery became depleted. Mercury batteries were first produced during World War II. They were smaller and their voltage did not decrease markedly until they were almost depleted. This relieved the user of the need to adjust the volume. In the 1950s, silver-oxide batteries were developed and began to replace the more toxic, environmentally hazardous mercury batteries. However, these batteries were expensive due to the silver content of this type of cell. Rechargeable batteries were tried, but without much commercial success. Today, most hearing aids are powered by zinc-air batteries. This type of battery offers clear advantages over both mercury (less negative impact on the environment) and silver (less expensive to manufacture). Zinc-air batteries require oxygen to produce an electric current. Once purchased, the airtight seal attached to each battery is removed. This allows air (including oxygen) to enter the battery where it stimulates the chemical reaction that produces an electric current. The removable airtight seal allows the battery to be stored for long periods of time with very little loss of power, as long as the seal remains attached. Zinc-air batteries cost an average of $1 apiece, with a useful life that ranges from a few days with a digital CIC to more than a month with a digital BTE instrument. EXTENDING BATTERY LIFE Hearing aid wearers tend to complain about poor battery life if they are required to replace the batteries more than once every week or two. We sought to address this dilemma. Since zinc-air batteries require oxygen to function, we reasoned that depriving the battery of oxygen during periods when it was not in use could extend its useful life. If a zinc-air battery was stored in an air-tight container with minimal dead volume so that the oxygen necessary for the battery to function was kept out, we theorized that the chemical reaction that produces current (and drains the battery) would come to a halt, a halt that could be easily reversed by exposing the battery to air again. To evaluate the effectiveness of this strategy, we used a voltmeter to measure the voltage of two fresh, size 10 zinc-air batteries, labeled “A” and “B.” The two batteries were used in a pair of digital CIC hearing aids during the day. At night or any other time when the hearing aids were not being used, battery A was removed and stored next to the aid while battery B was placed in a small, sealed tube with just enough space to contain the battery (Nalge Nunc CryoTube, part #65234). We repeated this procedure every day for 7 days. After a week, we measured the voltage again. Results showed an increase of approximately 20%-30% in the useful life of battery B. We repeated this experiment for several sets of batteries, and the results consistently showed increased life for batteries stored in the sealed tube. The same procedure was repeated with battery sizes 312, 13, and 675, with similar results. The question of whether a typical hearing aid user would go to the trouble of removing the battery every night and placing it in a cryotube has been considered. One of the authors (SG) is a hearing aid user and has been using this technique for many years. She is currently wearing a pair of CIC style hearing aids. She finds it convenient to remove the batteries at night and seal them in the cryotube, which is then placed in the carrying case along with the hearing aids (whose battery doors are left open so any collected moisture can evaporate). She has been using the technique with the last three models of hearing aids she has owned and finds that the increase in battery life more than compensates for the simple additional step required. In conclusion, the use of small cryogenic tubes, which are inexpensive and readily available, can significantly prolong the life of zinc-air batteries, resulting in reduced expense for hearing aid wearers.

Hearing aids' electromagnetic immunity to environmental RF fields

In this work, the electromagnetic interference on hearing aids was evaluated. Electromagnetic (EM) immunity tests on different types of hearing aids were carried out, using signals of intensity and modulation comparable to those present in the environment. The purpose of this work is to characterise the interference, establishing the immunity threshold for different frequencies and finding out which types of hearing aids are more susceptible, and in which frequency range. The tests were carried out in a GTEM cell on seven hearing aids, using AM and GSM signals in the radiofrequency (RF) range.

이명 치료를 위한 저절형 광역 소음발생개의 설계 및 구현

The tinnitus which is the one of the auditory disease is a phenomenon that the patients feel the sound in the ear or the head when there is no sound sources. There have been many therapies for this tinnitus so far, but it is known that the TRT (Tinnitus Retraining Therapy) is the most effective therapy. So we designed and developed the controllable white noise generator for TRT. It must be designed as small as possible for user's convenience, such as the ITE (In The Ear) type hearing aids. It used the thermal noise as the white noise source. And filter and tone control circuits are used at the end of the noise generation part to control the white noise characteristics. This link of the controllable circuits is used to change the white noise's characteristic for the various tinnitus patients' characteristic. we can confirm that the designed and implemented controllable white noise generator which is a ITE type operates properly by the experiments of filter and tone control circuit.

Changing characteristics of first-time hearing aid applicants in The Netherlands in the past decade

This study assessed changes in the characteristics of firsttime hearing aid applicants in the past decade. Age, gender, date, type and ear of first hearing aid and audiometry were determined for a sample of 705 firsttime hearing aid applicants. Thirteen cohorts resulted, according to the year of first visit to the dispenser. Differences in age, hearing loss, gender and type and ear of first hearing aid between cohorts were analysed. The mean age of first-time hearing aid users increased from 59.52 years in 1987 to 71.84 years in 1999. The mean pure-tone average hearing loss in the better ear (1, 2 and 4 kHz) decreased from 69.06 dB in 1987 to 51.86 dB in 1999. Relatively more males than females were fitted with hearing aids. Our conclusions are that people are being fitted with hearing aids at older ages and with smaller degrees of hearing loss.

Advances in the Hearing Sciences: Current Research and Clinical Applications

Advances in the Hearing Sciences: Current Research and Clinical Applications

Hearing aid satisfaction: what does research from the past 20 years say?

Hearing aid satisfaction is a pleasurable emotional experience as an outcome of an evaluation of performance. Many tools have been designed to measure the degree of satisfaction overall, or along the dimensions of cost, appearance, acoustic benefit, comfort, and service. Various studies have used these tools to examine the relationships between satisfaction and other factors. Findings are not always consistent across studies, but in general, hearing aid satisfaction has been found to be related to experience, expectation, personality and attitude, usage, type of hearing aids, sound quality, listening situations, and problems in hearing aid use. Inconsistent findings across studies and difficulties in evaluating the underlying relationships are probably caused by problems with the tools (eg, lack of validity) and the methods used to evaluate relationships (eg, correlation analyses evaluate association and not causal effect). Whether satisfaction changes over time and how service satisfaction contributes to device satisfaction are unclear. It is hoped that this review will help readers understand current satisfaction measures, how various factors affect satisfaction, and how the way satisfaction is measured may be improved to yield more reliable and valid data.

Survey of Adult Hearing Aid Service Expenditure and Provision in Denmark, Finland and the UK

The aim of this paper is to describe the provision of hearing aid services in Denmark, Finland and the United Kingdom (UK). A cross-sectional survey of adult hearing aid centres in Denmark, Finland and the UK was undertaken. Information requested included annual expenditure, staff levels, types of hearing aids provided, and patient characteristics. Data for the calendar year 2000 was requested in Denmark and Finland and for the financial year 2000/1 in the UK. Costs were converted into euros (€), at the following rates: 1€ &#114 = &#114 £0.62 &#114 = &#114 7.45 Danish Krone &#114 = &#114 5.95 Finnish Markka. The population covered by responding centres was equivalent to 80% in Denmark, 90% in Finland and 78% in the UK. Denmark spent the most per capita (€7.31), spent €670 per person fitted and provided the most aids (10.9 per thousand people). Finland spent €2.48 per capita, spent the most per person fitted (€924), but provided the fewest aids (2.7 per thousand people). The UK spent the least per capita (...

Próteses auditivas: estudo comparativo das dificuldades auditivas e do benefício da amplificação em pacientes usuários de amplificação não linear e linear.

<span class="texto">O objetivo deste trabalho foi quantificar e comparar as dificuldades auditivas e o benefício da amplificação em novos usuários de aparelho auditivo segundo as variáveis tipo de amplificação linear e não linear e tempo de uso, por meio do questionário de auto-avaliação APHAB. Foram avaliados 42 pacientes adultos com perda auditiva de grau leve a severo, distribuídos de acordo com o tipo de amplificação utilizada, sendo 13 pacientes usuários de amplificação não linear e 29 pacientes usuários de amplificação linear. O questionário de auto-avaliação APHAB, desenvolvido por Cox e Alexander em 1995, foi aplicado aos pacientes dos diferentes grupos antes da adaptação e após dois e seis meses. Para a análise estatística, foi utilizado o teste ANOVA com nível de significância de 5%. Os pacientes usuários de circuitos de amplificação linear apresentaram melhor desempenho nas subescalas FC (facilidade de comunicação), RV (reverberação) e BA (barulho ambiente), não sendo esta diferença estatisticamente significativa. O benefício obtido após dois e seis meses de uso da amplificação foi satisfatório. O desconforto para sons intensos, subescala (SI), foi maior para os pacientes usuários de amplificação linear. Não foram constatadas diferenças significativas no desempenho de pacientes usuários de circuitos de amplificação linear e não linear, porém houve uma tendência de os pacientes usuários de amplificação linear apresentarem menor dificuldade em diferentes ambientes acústicos. O benefício com o uso do aparelho de amplificação é satisfatório independentemente do tipo de amplificação e do tempo de uso.</span>

Modeling and predicting hearing aid outcome.

Following a brief tutorial on the application of factor analysis to hearing aid outcome measures, three studies of hearing aid outcome measures in elderly adults are presented and analyzed. Two of the studies were completed at Indiana University (IU-1 and IU-2), and one was a collaborative multisite study by the Veterans Administration and the National Institute of Deafness and other Communication Disorders (NIDCD/VA). IU-1 measured hearing aid outcome in 173 elderly wearers of single-channel, linear, in-the-ear hearing aids with output-limiting compression, whereas IU-2 obtained the same extensive set of outcome measures from 53 elderly wearers of two-channel, wide-dynamic-range compression, in-the-canal hearing aids. In the NIDCD/VA study, 333 to 338 participants wore three single-channel circuits in succession, with each circuit housed within an in-the-ear shell. The three circuits included in that study and in this analysis were: (1) linear with peak clipping, (2) linear with output-limiting compression, and (3) single-channel, wide-dynamic-range compression. Evaluation of the many outcome measures completed in each study using principal components factor analysis revealed that from three (both IU studies) to five (NIDCD/VA study) principal components captured the individual differences in hearing aid outcome. This was independent of hearing aid type (in-the-ear or in-the-canal) and circuitry. Subsequent multiple regression analyses of individual differences in performance along each dimension of hearing aid outcome revealed that these individual differences could be accounted for reasonably well by various prefit variables for some dimensions of outcome, but not others. In general, measures of speech recognition performance were well accounted for by prefit measures, with the best predictors being hearing loss, cognitive performance, and age. Measures of hearing aid usage were less well accounted for by prefit measures, with the most accurate predictor of current hearing aid use being prior hearing aid use. The outcome dimension accounted for most poorly was that associated with hearing aid satisfaction, with subjective measures of aided sound quality being the best predictor of performance along this dimension of hearing aid outcome. Additional multicenter, large-scale studies are needed to develop more complete models of hearing aid outcome and to identify the variables that influence various aspects of hearing aid outcome. It is only through this additional research that it will be possible to optimize outcome for hearing aid wearers.

Hearing aid construction with electronic components encapsulated in soft polymeric body

A hearing aid instrument of the in-the-ear type (and preferably CIC) provides a plate member with electronic hearing aid components mounted thereto. The plate member is preferably of a harder material such as hard plastic. A soft polymeric body is bonded to the plate member and encapsulates preferably a plurality of the electronic hearing aid components. The body is soft and is shaped to conform to the ear canal of the user. The soft polymeric body and encapsulated electronic hearing aid components define a soft structure compliant to the ear canal during use and that is substantially solid and free of void spaces between at least some of the components and the ear canal. This combination of soft compliant structure and encapsulated electronic hearing aid components addresses problems of peripheral leakage, poor fit, pivotal displacement that occurs with jaw motion and internal cross talk of components housed in prior art hollow type hearing aids.

Performance of Custom-Fit versus Fixed-Format Hearing Aids for Precipitously Sloping High-Frequency Hearing Loss

This study compared the real-ear response provided by custom-fit hearing aids to the closest matching fixed-format disposable hearing aids in patients with precipitous high-frequency hearing loss. Laboratory and field measures of aided performance were obtained to compare patient performance with the custom-fit and fixed-format hearing aids. In addition, coupler versus real-ear response differences were compared for the two hearing aid types. The results revealed that relatively close approximations to the real-ear aided responses of the custom-fit instruments were possible for most participants using seven fixed acoustic formats. No significant differences in mean performance between the two instrument types were observed for aided speech recognition or field ratings of aided performance, although mean patient satisfaction was lower for the disposable hearing aids. The real-ear to coupler difference was greater for the disposable hearing aid than for the custom-fit instruments, presumably owing to its deeper insertion into the ear canal.

Nonlinear digital hearing aid with near-instantaneous amplitude compression.

We designed a new type of nonlinear digital hearing aid (TD-1) with near-instantaneous amplitude compression for sensorineural hearing-impaired people. The amplification method utilized by the TD-1 normalizes the signal waveforms within a time window bounded by two adjacent positive going zero-crossing points. The signals within this window are amplified so that the maximum amplitude reaches a preset value, thus allowing a consistent peak amplitude to be maintained. To test this, we examined the efficacy of the TD-1 device in 31 patients with sensorineural hearing loss. When tested for recognition of Japanese sentences in a quiet environment, 7 of 25 (28.0%) subjects wearing the TD-1 showed a 20% or greater increase in the maximum intelligibility score than that obtained when wearing their own linear hearing aids. In addition, 7 of 31 (22.6%) subjects showed the same increase with the TD-1 relative to that obtained when they wore HA70 or HA73 devices (Rion Co., Ltd., Tokyo, Japan), which are conventional analogue hearing aids. These results indicate that TD-1 can be effective for patients with sensorineural hearing loss.

Wireless Telephone-Hearing Aid Electromagnetic Compatibility Research at the University of Oklahoma

A multiphase study examining electromagnetic compatibility (EMC) between wireless digital telephones and hearing aids has been under way at the University of Oklahoma EMC Center since May 1995. In a phase 1 clinical study involving 68 hearing aid wearers, interference varied significantly by telephone technology, hearing aid type, and hearing loss characteristics. More than 80 percent of the tests resulted in either no interference or a detection threshold distance less than 1 meter. Metallic shielding of the units yielded positive results. Various elements of phase 2 involved instrument-based tests of hearing aid interference using telephones in a sound-isolation chamber and radio frequency signals in a waveguide, along with clinical studies of speech-to-interference ratios, all leading to the development of standards of measurement and performance criteria for telephone emissions and hearing aid immunity. Results to date confirm that bystander interference is of less concern than user interference, which is the focus of continuing research.