A comparison of single-channel linear amplification and two-channel wide-dynamic-range-compression amplification by means of an independent-group design

The present study used an independent-group design to compare the benefits provided by binaural, single-channel, linear, full-shell in-the-ear hearing aids and binaural, 2-channel, wide-dynamic-range-compression in-the-canal hearing aids in groups of older hearing aid wearers. Hearing aid outcome measures were obtained at both 1-month (n = 53) and 6-month (n = 34) postfit intervals with each device. Outcome measures included multiple measures of speech-recognition performance and self-report measures of hearing aid benefit, satisfaction, and usage. Aided sound-quality measurements were also obtained. Although both devices provided significant benefits to the wearers, there were no significant differences in the benefits provided by either device at the 1-month or 6-month postfit intervals.     

Hearing-aid outcome measured following one month of hearing aid use by the elderly.

This study reports the results of a large number of hearing-aid outcome measures obtained from 173 elderly hearing-aid wearers following one month of hearing-aid use. All participants in this study were fit binaurally with identical full-concha in-the-ear (ITE) hearing aids having linear Class-D amplifiers with output-limiting compression. Outcome measures included several measures of speech recognition, as well as several self-report measures of hearing-aid performance, benefit, satisfaction, and use. Comparison of mean data from this sample of hearing-aid wearers to other larger sets of data, obtained previously for several of these measures of hearing-aid outcome evaluated in isolation, indicated that the participants in this study were representative of the participants in other larger-scale studies. Subsequent principal-components factor analysis of the data from this study indicated that there were seven distinct dimensions of hearing-aid outcome. Attempts to document the effectiveness and efficacy of hearing aids for elderly persons with impaired hearing will be most complete when assessing performance along all seven dimensions of hearing-aid outcome. Clinically efficient procedures for doing so are discussed.     

A comparison of two measures of hearing aid satisfaction in a group of elderly hearing aid wearers

OBJECTIVE: The objective of this study was to compare the results of two measures of hearing aid satisfaction, an indirect measure (Satisfaction with Amplification in Daily Living, SADL; Cox & Alexander, 1999) and a direct measure (an expanded version of the MarkeTrak-IV survey; Kochkin, 1996), in a group of elderly hearing aid wearers. DESIGN: A total of 43 elderly hearing aid wearers completed both satisfaction measures (order counterbalanced across wearers) after 1 mo of wearing 2-channel wide dynamic range compression (WDRC) in-the-canal (ITC) hearing aids. A correlational research design was employed. RESULTS: The elderly hearing aid wearers in this study yielded results on each measure of hearing aid satisfaction that were generally consistent with those found previously in larger groups of similar samples. The correlation between each measure of satisfaction (r = 0.75) was positive, moderately strong, and significant (p < 0.01) for the global scores of the SADL and MarkeTrak-IV scales. CONCLUSIONS: Although different approaches to the measurement of satisfaction were followed in the development of the SADL (indirect approach) and the MarkeTrak-IV (direct measurement) scales, similar results were obtained with each scale. The 15-item SADL instrument, however, is much shorter than the MarkeTrak-IV instrument and, as a result, is more efficient to administer clinically.     

The effects of venting on in-the-ear, in-the-canal, and completely-in-the-canal hearing aid shell frequency responses: real-ear measures.

The acoustic effects of 1-, 2-, and 3-mm vents were investigated with in-the-ear, in-the-canal, and completely-in-the-canal hearing aid shells. Real-ear sound pressure level measures were obtained from unvented and vented shells with 12 adults. In general, with increasing vent size, a statistically significant (p < .05) increase in the amount of low-frequency reduction, an upward shift in vent cutoff frequencies, and an upward shift in vent-associated resonances occurred for all hearing aid shell styles. There was no significant change in the slope of the low-frequency reduction across all hearing aid shell styles (p > .05), albeit the frequency response curves were shifted upward in frequency with increasing vent diameters. Only with the in-the-ear and completely-in-the-canal hearing aid shells were statistically significant (p < .05) differences found with the magnitude of vent-associated resonance as a function of vent diameter, and these differences were not consistent across the different styles. These findings suggest that venting may be used effectively to tune low-frequency responses in custom in-the-ear hearing instruments.     

Hearing aid manipulation skills in an elderly population: a comparison of ITE, BTE, and ITC aids

In-the-ear, in-the-canal and behind-the-ear hearing aids were compared for ease of management by elderly people. Two hundred and forty-four clients were randomly assigned to be fitted with one aid type, and rated for ability to perform the manipulative tasks necessary to enable effective use of the aid. It was found that in-the-ear aids were easiest to use, that females experienced greater difficulties in manipulation than males and that some tasks were easier to perform and more quickly learned than others. The findings are discussed in terms of design requirements and aid fitting practices.     

NIDCD/VA hearing aid clinical trial and follow-up: background

This report provides background regarding the Long Term Follow-Up of Patients in the NIDCD/VA Hearing Aid Clinical Trial study and serves as an introduction to the detailed reports that follow in this issue of Journal of the American Academy of Audiology. The authors investigated five- to seven-year benefit/satisfaction in participants from the original NIDCDNA Hearing Aid Clinical Trial. The new study was designed to investigate current use of the original study hearing aids, to compare changes in selected audiological measures, and to assess possible predictors of long-term hearing aid use. The outcome measures included estimates of speech intelligibility in quiet and noise, self-reported patterns of hearing aid usage, self-reported estimates of activity limitations and quality-of-life issues, estimates of hearing aid satisfaction, and self-reported hearing aid benefit. Overall, the short-term benefits of hearing aid use observed during the original trial were noted to persist in the long term.     

The advantages and disadvantages of ITC, ITE and BTE hearing aids: diary and interview reports from elderly users

The advantages and disadvantages of in-the-canal (ITC), in-the-ear (ITE) and behind-the-ear (BTE) hearing aids for elderly aid users were examined. Two hundred and forty four clients were randomly assigned to one of the three aid types from seven hearing aid manufacturers. The clients' perceived help from their fitting, and the degree of difficulty they encountered over a range of listening situations and environments were rated using a daily diary and a structured interview. Findings indicated that for elderly clients there were no large practical advantages for one aid type over another. While ITC and ITE aids were rated more highly than BTE's in background noise, all three aid types were rated as relatively poor in background noise as well as in groups, in the wind, when using the telephone and in the localisation of sound. All three aid types were rated equally and well for performance in one-to-one conversation in quiet, and for listening to television and radio. Hours of use and reasons for non-use are presented, as are clients' reports on cosmetic issues, manipulative ease and overall satisfaction level with their aids.     

Factors affecting the use and perceived benefit of ITE and BTE hearing aids.

The aim of the present study was to investigate factors that might affect hearing aid use, satisfaction and perceived benefit. A further aim was to look at which variables affect the choice of hearing aid, in particular, an in-the-ear (ITE) versus a behind-the-ear (BTE) device. Twenty-nine elderly hearing-impaired people with a mild-to-moderate hearing loss were fitted with both an ITE and a BTE hearing aid with similar electroacoustic performance. Both hearing aids were linear with output compression limiting and were fitted in a randomized order. After wearing each device for a six-week period, subj ets were asked to select the hearing aid they preferred. Variables significantly related to hearing aid choice, use and perceived benefit included ease of management, accuracy with which the NAL-R insertion gain target was achieved, earmould comfort and the type of hearing aid the client preferred initially.     

Longitudinal changes in hearing aid satisfaction and usage in the elderly over a period of one or two years after hearing aid delivery

OBJECTIVE: The objective of this study was to measure hearing aid satisfaction and usage for extended periods of time, up to 2 yr after hearing aid delivery, to determine whether longitudinal changes occur in the elderly for these outcome measures. DESIGN: A longitudinal study of hearing aid satisfaction and usage was performed in a group comprised of 134 elderly hearing aid wearers with these outcome measures obtained at 1, 6, and 12 mo postfit. A total of 49 of the original 134 elderly returned 2 yr after hearing aid delivery to complete the satisfaction and usage measures again. Multiple self-report measures of hearing aid satisfaction and hearing aid usage were obtained at each follow-up session. RESULTS: Most between-interval comparisons of the various measures of satisfaction and usage failed to reveal significant changes over time. However, some significant changes were observed in both satisfaction and usage. When such changes occurred, they were always in a direction that suggested a decrease in satisfaction or usage over time. Correlations across various postfit interval pairs were found to be positive, statistically significant, and moderate to strong in strength for all measures of satisfaction and usage. CONCLUSIONS: Although there were slight declines in hearing aid usage and satisfaction over time, measures of hearing aid satisfaction obtained at 1 mo postfit and of hearing aid usage obtained at 6 mo postfit are generally stable for up to 2 yr after hearing aid delivery.     

Impact of compression and hearing aid style on directional hearing aid benefit and performance.

OBJECTIVE: To evaluate the impact of low-threshold compression and hearing aid style (in-the-ear [ITE] versus behind-the-ear [BTE]) on the directional benefit and performance of commercially available directional hearing aids. DESIGN: Forty-seven adult listeners with mild-to-moderate sensorineural hearing loss were fit bilaterally with one BTE and four different ITE hearing aids. Speech recognition performance was measured through the Connected Speech Test (CST) and Hearing in Noise Test (HINT) for a simulated noisy restaurant environment. RESULTS: For both the HINT and CST, speech recognition performance was significantly greater for subjects fit with directional in comparison with omnidirectional microphone hearing aids. Performance was significantly poorer for the BTE instrument in comparison with the ITE hearing aids when using omnidirectional microphones. No differences were found for directional benefit between compression and linear fitting schemes. CONCLUSIONS: No systematic relationship was found between the relative directional benefit and hearing aid style; however, the speech recognition performance of the subjects was somewhat predictable based on Directivity Index measures of the individual hearing aid models. The fact that compression did not interact significantly with microphone type agrees well with previously reported electroacoustic data.     

Clinical study of Widex Senso on first-time hearing aid users.

Using psychoacoustic tests and questionnaires, the aim of this study was to clinically test Widex Senso (WS) versus analogue hearing aids on 200 first-time wearers. Half of the participants were selected at random for fitting with the behind-the-ear model (WS C8) or the in-the-canal model (WS CX). On a group basis, WS was found to provide more benefit than a palette of 29 analogue, modern hearing aid models from 10 manufacturers. Only 3 of 100 subjects changed from WS to another hearing aid. On average, the abbreviated profile of hearing aid benefit (APHAB) (Cox & Alexander, 1995) demonstrated superior performance for WS, i.e. no conflict existed between high comfort and high speech recognition. Median aided frequency-modulated tone thresholds in the sound field were better than 25 dB HL at frequencies up to 4 kHz inclusive. A distinct mean aided improvement of speech threshold in competing speech of 2.5 dB was found in both groups.     

The "hearing aid effect" 2005: a rigorous test of the visibility of new hearing aid styles

PURPOSE: The visibility of open ear (OE) styles of hearing instruments was rigorously investigated for their potential to reduce the stigma of wearing hearing aids. METHOD: Three groups of 50 young adults (150 total) rated the visibility of 6 hearing aid styles-OE, invisible completely-in-the-canal (CIC), mini in-the-canal (m-ITC), half- and full-shell in-the-ear (ITE), and behind-the-ear (BTE)-worn by a peer model with revealing hairstyle, photographed from 2 ft and at 3 different angles (45 degrees, 90 degrees, and 135 degrees). RESULTS: CIC was rated significantly most "invisible" at 45 degrees and 90 degrees, OE and m-ITC were next at those angles, and OE and BTE were least invisible at 135 degrees. CONCLUSIONS: The findings have implications for counseling potential users who are reluctant to try hearing aids for cosmetic reasons.     

Norms for the international outcome inventory for hearing aids

The International Outcome Inventory for Hearing Aids (IOI-HA) is a seven-item survey that was developed for use in research settings to facilitate comparison of data across diverse investigations. The inventory also has potential applications in clinical evaluation of hearing aid fitting outcomes. This article reports the development of norms for the inventory that are suitable for use with group data in research applications, and individual data in a clinical setting. The normative group was defined as adults fitted bilaterally with analog, single-channel, single-memory, compression processing, in-the-ear hearing aids. There were 154 subjects. Associations between outcomes and demographic variables (e.g., gender, hearing loss, etc.) were explored, and several relationships were seen. Based on these data, two sets of norms were derived. The appropriate set will depend on the individual's reported subjective hearing problems without amplification.     

Organization and administration of the NIDCD/VA Hearing Aid Clinical Trial

This article describes the organization and administration of the NIDCD/VA Hearing Aid Clinical Trial. The trial involved a total of 360 patients with bilateral, sensorineural hearing loss from eight VA Medical Centers to study three different hearing aid circuits in a three-period, three-treatment crossover design. Strong central coordination of such a complex multi-center clinical trial is essential to its success. The trial took more than 5 years to design, implement, and complete. This timeline is also described.     

Changes in hearing-aid benefit following 1 or 2 years of hearing-aid use by older adults.

This study reports the results of a large number of hearing-aid benefit measures obtained from 134 elderly hearing-aid wearers during the first year of hearing-aid usage. Benefit measures were obtained after 1 month, 6 months, and 1 year of hearing-aid use by all participants. In addition, follow-up measurements of hearing-aid benefit were performed on 49 of these same hearing-aid wearers following 2 years of hearing-aid use. All participants in this study were fit binaurally with identical full-concha in-the-ear (ITE) hearing aids that used linear Class-D amplifiers with output-limiting compression. Benefit measures included several objective tests of speech recognition, as well as the subjective self-report scales of the Hearing Aid Performance Inventory (HAPI; B. E. Walden, M. E. Demorest, & E. L. Hepler) and the Hearing Handicap Inventory for the Elderly (HHIE; I. Ventry & B. Weinstein, 1982). Although group means changed only slightly over time for all of the benefit measures, significant differences were observed for some of the benefit measures, especially among the subjective, self-report measures of benefit. In almost all of the cases exhibiting significant changes, performance was significantly worse (less benefit) at both the 6-month and 1-year post-fit interval compared to the measurements at 1 month post-fit. In general, the individual data from the 134 participants who were represented in the 1-year data set were consistent with the trends in the group data described above. Regarding longer term changes in benefit following 2 years of hearing-aid use, minimal changes were again observed. In all, there was little evidence for acclimatization of hearing-aid benefit in this study in either the group or the individual data.     

A comparison of different binaural hearing aid systems for sound localization in the horizontal and vertical planes

Three groups of hearing-impaired listeners who had been fitted binaurally with behind-the-ear (BTE), in-the-ear (ITE), or in-the-ear-canal (ITC) hearing aids were tested on spatial localization function for sources in the frontal horizontal and vertical planes. No significant differences in unaided performance were observed between the groups, nor between that and aided performance in the BTE and ITE wearers. ITC wearers, by contrast, showed a deterioration in aided over unaided performance. From observations of performance when each group wore temporary fittings of the other two types of system, and from the performance of a non-impaired control group, it appears that the performance decrement for the ITC wearers was due to their own particular systems although specific reasons for this decrement could not be identified. In all conditions, aided and unaided, vertical plane localization was markedly disrupted in all the hearing impaired groups. It was also disrupted, to a lesser but still substantial extent, in aided conditions for the non-impaired listeners.     

Maximum real-ear gain of in-the-ear hearing aids

Three hearing aid manufacturers provided custom full-shell in-the-ear hearing aids for each of 3 hearing-impaired subjects. Each manufacturer was instructed that the hearing aids should provide the maximum possible acoustic gain within the limits of hearing aid shell size and available components. Coupler gain, insertion gain, and functional gain were measured for each hearing aid. Gain measures were made with the volume control at either the full-on setting or the highest setting possible before the onset of acoustical feedback. Full-on coupler gain curves were similar across all nine hearing aids. Individual differences in concha/ear canal size and in the fit of the hearing aids produced substantial variance in insertion gain across hearing aids. Peak insertion gain varied from 41 to 58 dB. If 10 dB reserve gain is allowed, the range of estimated peak use gain from these maximum-gain in-the-ear hearing aids is 31-48 dB.     

Clinical evaluation of a two-channel amplitude compression hearing aid

Twelve experienced hearing aid users with mild to moderate hearing loss used two new, commercially available behind-the-ear amplitude compression hearing aids for 1 month each. One aid was a single-channel device; the other was a two-channel aid. All subjects had used other compression aids for at least 1 year. Performance in real-life situations with the personal aid and the two trial aids was evaluated by the Hearing Performance Inventory (HPI). Another questionnaire probed subjective preference for the three aids and willingness to purchase each of the trial aids. The major HPI finding was an equal performance superiority for the two trial aids over the personal aid for half the subjects. The preference/purchase questionnaire results indicated that the two-channel aid had some sound quality advantages, but was unacceptable physically. The single-channel trial was clearly preferred over the personal and two-channel device.     

Psychosocial correlates of hearing aid adjustment

Despite considerable evidence regarding the detrimental effects of untreated hearing loss, there continues to be an underutilization of hearing aids by adults. The Long Term Follow-Up of Patients in the National Institute on Deafness and Other Communication Disorders/Veterans Affairs (NIDCD/VA) Hearing Aid Clinical Trial (Cooperative Studies Program [CSP] 418-A) provided the opportunity to compare a number of potential psychosocial influences and outcomes for hearing aid users and nonusers from the original CSP 418 study. The Communication Profile for the Hearing Impaired (CPHI) results provide compelling evidence of hearing aid benefit. Mean Communication Performance (CP) scores for hearing aid users on the Social, Work, and Home scales improved significantly from the original CSP 418 administration. For nonusers, there were no significant CPHI changes from the previous administration. Although hearing aid users and nonusers did not differ in optimism, this parameter was correlated with personal adjustment, measured via the CPHI. Hearing aid use was associated with the perception of major life events, such as illness, retirement, and so forth.