Using conjoint analysis to examine the importance of hearing aid attributes

OBJECTIVE: To introduce conjoint analysis (CA) as a method to explain choice decisions of hearing aid users and to measure the contributions of different hearing aid attributes involved. DESIGN: The study was conducted using CA, a method that is well established in marketing, but has not been used for hearing aid research. CA examines the contributions (importance) various attributes make to overall preference judgements. It is based on the premises that objects (i.e., hearing aids) can be described as different combinations of several attributes. The relative importance of the attributes is estimated from integral judgements of hypothetical hearing aids. The advantages of CA are a more realistic presentation of complete products instead of isolated attributes and the consideration of trade-offs between the features. The following attributes selected from 12 features in a prestudy were included in the application: speech perception in quiet, speech perception in noise, handling, sound quality, localization, and feedback. 93 randomly chosen experienced hearing aid wearers participated in the survey. RESULTS: It was found that the attributes concerning speech perception were by far most important. Speech discrimination in quiet and in noise were almost equally significant and contributed with 56% to the preference decisions of the subjects. The remaining attributes showed values in the range of 10% to 12%. When comparing various subgroups dependent on age, sex, hearing loss, satisfaction, etc., significant differences concerning the preferences were found. Elder and female subjects attached greater importance of the attribute "handling" whereas younger patients judged "speech in noise" more important. In general, subjects with greater hearing loss considered speech intelligibility in quiet to be more important than in noisy surroundings. Moreover, sound quality seems to be a significant indicator for satisfaction with the hearing aid. CONCLUSIONS: This study proposes CA as a survey technique to examine individual preferences for hearing aids. Several assumptions about the importance of hearing aid features for different groups of users could be confirmed quantitatively. Segmentation showed valid results depending on socio-demographic and user-specific parameters. The method used and the results are of interest for audiologists as well as the hearing aid industry. They provide valuable tools for future hearing aid design and should be considered in the development of self-assessment inventories.     

Demands on hearing aid features--special signal processing for elderly users?

Age-related effects on several parameters of hearing aid provision, comprising the importance of various hearing aid attributes, the main reason for dissatisfaction, and a measure for aided performance, were examined. When comparing two subgroups of younger and elderly hearing aid users, a significant difference occurred for the importance of the attribute 'handling', whereas all other features examined showed only differences in trends. The question posed for the main reason for dissatisfaction with the hearing aids revealed no significant contrasts. Problems with the instruments in several listening situations were investigated by means of the Gothenburg Profile. Items related to communication in groups showed significant differences between younger and older subjects, but only non-significant contrasts remained when the mean hearing losses of the two subgroups were properly matched. Based on the data presented, some age-related concerns should be taken into account in hearing-aid provision for elderly users, but special signal processing does not seem to be necessary.     

Acceptable noise level (ANL) with Danish and non-semantic speech materials in adult hearing-aid users

Abstract Objective: The acceptable noise level (ANL) test is used for quantification of the amount of background noise subjects accept when listening to speech. This study investigates Danish hearing-aid users' ANL performance using Danish and non-semantic speech signals, the repeatability of ANL, and the association between ANL and outcome of the international outcome inventory for hearing aids (IOI-HA). Design: ANL was measured in three conditions in both ears at two test sessions. Subjects completed the IOI-HA and the ANL questionnaire. Study sample: Sixty-three Danish hearing-aid users; fifty-seven subjects were full time users and 6 were part time/non users of hearing aids according to the ANL questionnaire. Results: ANLs were similar to results with American English speech material. The coefficient of repeatability (CR) was 6.5-8.8 dB. IOI-HA scores were not associated to ANL. Conclusions: Danish and non-semantic ANL versions yield results similar to the American English version. The magnitude of the CR indicates that ANL with Danish and non-semantic speech materials is not suitable for prediction of individual patterns of future hearing-aid use or evaluation of individual benefit from hearing-aid features. The ANL with Danish and non-semantic speech materials is not related to IOI-HA outcome.     

Hearing difficulties, uptake, and outcomes of hearing aids in people 85 years of age

OBJECTIVE: The aim of this study was to investigate self-reported hearing difficulties, uptake, and hearing-aid outcomes and their relationships to demographic, cognitive, psychosocial, and health variables in 85 year olds. DESIGN AND STUDY SAMPLE: Three hundred and forty-six elderly adults participated in a survey that included questionnaires and home visits. Fifty-five percent of participants admitted to having hearing difficulties, and 59% of these owned hearing aids. The participants' most frequently cited reason for not acquiring hearing aids was that they did not think their hearing problem was perceived as severe enough. Participants with hearing difficulties who did not own hearing aids showed worse general and mental health. Many of the elderly participants were successful in their rehabilitation, and their hearing-aid outcomes were similar to those of a younger group, with the exception of a greater proportion of non-users among the elderly. CONCLUSION: Many older people with self-reported hearing difficulties do not acquire hearing aids, despite this study's findings that older people are likely to have success with hearing rehabilitation. It is important to make greater efforts to try to increase elderly adults' awareness of hearing loss and the benefits of hearing rehabilitation.     

Acceptable noise level (ANL) with Danish and non-semantic speech materials in adult hearing-aid users

Abstract

Objective: The acceptable noise level (ANL) test is used for quantification of the amount of background noise subjects accept when listening to speech. This study investigates Danish hearing-aid users’ ANL performance using Danish and non-semantic speech signals, the repeatability of ANL, and the association between ANL and outcome of the international outcome inventory for hearing aids (IOI-HA). Design: ANL was measured in three conditions in both ears at two test sessions. Subjects completed the IOI-HA and the ANL questionnaire. Study sample: Sixty-three Danish hearing-aid users; fifty-seven subjects were full time users and 6 were part time/non users of hearing aids according to the ANL questionnaire. Results: ANLs were similar to results with American English speech material. The coefficient of repeatability (CR) was 6.5–8.8 dB. IOI-HA scores were not associated to ANL. Conclusions: Danish and non-semantic ANL versions yield results similar to the American English version. The magnitude of the CR indicates that ANL with Danish and non-semantic speech materials is not suitable for prediction of individual patterns of future hearing-aid use or evaluation of individual benefit from hearing-aid features. The ANL with Danish and non-semantic speech materials is not related to IOI-HA outcome.     

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.     

Subjective ratings of noise-reduction hearing aids

The effectiveness of seven commercially available noise-reduction hearing aids was evaluated using subjective ratings of continuous discourse. Subjective scales of listening comfort, speech quality, speech understanding, noise interference, and overall liking were used. Fifteen experienced hearing-aid users participated. Two hearing aids that used amplitude compression (Audiotone A-54 and Telex 363C), two hearing aids that used the Zeta Noise Blocker (two versions of a Maico SP147), and three hearing aids that proportionally attenuated the low-frequencies (Rion HB-69AS, Richards ASE-B, and Siemens 283 ASP) were evaluated. None of the noise-reduction hearing aids significantly altered group performance on any subjective scale. Individually, however, subjects responded differently to different noise-reduction hearing aids, indicating that some noise-reduction hearing aids may help some hearing-impaired individuals.     

Utility and importance of hearing-aid features assessed by hearing-aid acousticians

Modern hearing instruments include many features addressing situation-specific and user-related amplification. The main tasks of the acoustician are the appropriate choice of hearing instruments and fitting them to hearing impaired individuals. This study aims at investigating the utility and importance of several hearing-aid features as assessed by hearing-aid acousticians. For this purpose, eight different hearing-aid features with three levels each are addressed in a discrete-choice experiment. Preferences for systematically varied combinations of the features are assessed with 143 acousticians, using an adaptive conjoint analysis conducted via the Internet. Based on the preference data, utility and importance of the features are calculated. Highest utility and importance are found for noise cancellation and directional microphones. Outcome of these two features do not differ significantly. In contrast, data management functions, that is, self-learning options, show lowest importance. Though the acousticians' professional experience reveal statistically significant influence on the assessment of some of the features' utility and importance, a clear impact of sociodemographic or subject-specific factors on the outcome cannot be found. The study can be seen as a first approach to determine the estimation of basic hearing-aid features assessed by acousticians. Results show the outstanding utility and importance of features addressing speech perception in adverse listening situations. Furthermore, the outcome reveals reservations of the acousticians regarding self-learning options of the instruments.     

Development of a hearing aid self-efficacy questionnaire

Discontinued hearing-aid use is caused by a number of factors, most of which may lead to low hearing-aid self-efficacy (i.e. low confidence in one's ability to B a successful hearing-aid user). This paper describes the development of the Measure of Audiologic Rehabilitation Self-Efficacy for Hearing Aids (MARS-HA), which was constructed in accordance with published recommendations for self-efficacy questionnaire development. The psychometric properties of the MARS-HA were evaluated with new and experienced hearing-aid users. The results revealed strong internal consistency and good test-retest reliability in both groups, with the following subscales identified both for the new users and the experienced users: (1) basic handling, (2) advanced handling, (3) adjustment to hearing aids, and (4) aided listening skills. Validity was established through the examination of expected differences based on group comparisons, training effects, and the impact of particular hearing aid features. The MARS-HA is a reliable and valid measure of hearing-aid self-efficacy and can be used to assist clinicians in identifying areas of low confidence that require additional audiologic training.     

Use and benefit of hearing aids in the tenth decade--and beyond

The purpose of this study was to evaluate the use and benefit of hearing aids in 185 hearing-disabled subjects born before 1900, consecutively fitted with a hearing aid during the first 6 months of 1989. Information from 138 (75%) subjects, 117 females and 21 males with a median age of 93 years (range 90-107), was obtained from a questionnaire, which was mailed 4-6 months after the fitting procedure. The questionnaire included questions concerning use of the hearing aid(s), self-reported benefit, handling problems, overall satisfaction/dissatisfaction, social and domiciliary situation and self-reported visual capacity. Among these elderly subjects 75% had previously been provided with hearing aids, while 25% were first-time users. The results demonstrate that 76% use the hearing aid(s) at home and in small groups, and that 51% use the hearing aid(s) each day; however, 35% did not respond to this question. 64% expressed general satisfaction with their aid(s). Despite instruction and counselling, handling problems were frequently present. In those previously fitted with hearing aids a higher rate of time-related use and satisfaction was present, and handling problems were less frequent than in the first-time applicants. It is concluded that elderly hearing-impaired subjects in the tenth decade use and benefit from hearing aids; however, more problems concerning use and benefit of hearing aids are present in this age group than in the younger age groups.     

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.     

Toleration of background noises: relationship with patterns of hearing aid use by elderly persons

One of the frequently quoted reasons for the rejection of hearing aids is amplification of background noise. The relationship between hearing aid use and toleration of background noise was assessed. Four groups of elderly subjects (at least 65 years old) and one group of young subjects with normal hearing participated in the study. Each group consisted of 15 subjects. The young subjects and elderly subjects in one group with relatively good hearing were tested for comparison with the hearing-impaired subjects. Elderly subjects in the three remaining groups had acquired hearing losses and had been fitted with hearing aids. The subjects were assigned to three groups on the basis of hearing aid use: full-time users, part-time users, and nonusers. The amount of background noise tolerated when listening to speech was tested. The speech stimulus was a story read by a woman and set at an individually chosen most comfortable level. The maskers were a babble of voices, speech-spectrum noise, traffic noise, music, and the noise of a pneumatic drill. There was a significant interaction between groups and noises. The full-time users tolerated significantly higher levels of music and speech-spectrum noise than part-time users and nonusers. In addition, the full-time users, but not the part-time users, assessed themselves as less handicapped in everyday functions when they wore hearing aids than when they did not wear their hearing aids.     

Development of a hearing aid self-efficacy questionnaire

Discontinued hearing-aid use is caused by a number of factors, most of which may lead to low hearing-aid self-efficacy (i.e. low confidence in one's ability to B a successful hearing-aid user). This paper describes the development of the Measure of Audiologic Rehabilitation Self-Efficacy for Hearing Aids (MARS-HA), which was constructed in accordance with published recommendations for self-efficacy questionnaire development. The psychometric properties of the MARS-HA were evaluated with new and experienced hearing-aid users. The results revealed strong internal consistency and good test-retest reliability in both groups, with the following subscales identified both for the new users and the experienced users: (1) basic handling, (2) advanced handling, (3) adjustment to hearing aids, and (4) aided listening skills. Validity was established through the examination of expected differences based on group comparisons, training effects, and the impact of particular hearing aid features. The MARS-HA is a reliable and valid measure of hearing-aid self-efficacy and can be used to assist clinicians in identifying areas of low confidence that require additional audiologic training.     

In-the-canal hearing aids. Their use by and benefit for the younger and elderly hearing-impaired

The present investigation was performed in order to evaluate the use and benefit of in-the-canal hearing aids (ITC-HAs; Dan 131) in a group of elderly and younger subjects. An extensive questionnaire was mailed to 256 hearing aid users. The responding group comprised 220 subjects (86%) and consisted of 108 males and 112 females with a median age of 69 years, range 11-89. In order to compare between the elderly and the younger subjects, the material was subdivided into two groups: one less than 70 years (n = 113), and the other greater than or equal to 70 years (n = 107). The median values of the average threshold at 500, 1000, 2000, and 4000 Hz for the right and/or left ear (which was fitted with hearing aid(s] was 43 dB HL, thus indicating a moderate hearing loss. The questionnaires demonstrated that 74% of the subjects used their ITC-HA every day, 28% used the aid very seldom and only 1% never used the hearing-aid. 74% of the total sample were satisfied or very satisfied with the ITC-HA, while 19% were not entirely satisfied or dissatisfied. No significant differences between the elderly and the younger groups were found concerning time-related use, situational use, self-assessed effect, or general satisfaction/dissatisfaction with the aid. The elderly found the aid significantly more troublesome to deal with. It is concluded that hearing-impaired subjects with moderate hearing losses use and benefit from ITA-HAs, regardless of age. However, a ITC-HA should be recommended for the elderly only if they can be offered thorough individual instruction.     

In-the-ear hearing aids. The use and benefit in the elderly hearing-impaired

Preliminary clinical experiences with in-the-ear hearing aids (ITE-HAs) have been promising, and a beneficial effect has been demonstrated in younger hearing-impaired subjects. However, the subjects applying for audiological examination and rehabilitation are predominantly elderly people (i.e. greater than or equal to 70 years). The present questionnaire examination was performed in order to evaluate the use and benefit of ITE-HAs also in the elderly hearing-impaired, and compare with the effect in younger subjects. An extensive questionnaire was sent 6 months after hearing aid fitting to all patients fitted with ITE-HAs. A total number of 693 subjects corresponding to 80% responded to the questionnaire. 70% of the patients are greater than or equal to 70 years and 23% are above the age of 80 years. The results demonstrate that the elderly hearing-impaired use the hearing aids predominantly in situations when listening to television and in small groups; 64% use their hearing aids the whole day and only 6% never use the aids; with increasing age were indicated increasing handling problems, both concerning change of battery, handling of volume control, and insertion of the aid into the ear canal. Only 8% of the patients were dissatisfied with the cosmetic appearance of the hearing aids, the dissatisfaction being more frequent in the young age group below 70 years (16%) than above the age of 70 years (9%). It is concluded that also the elderly hearing-impaired use and benefit from ITE-HAs.     

Comparison of speech perception in background noise with acceptance of background noise in aided and unaided conditions.

Background noise is a significant factor influencing hearing-aid satisfaction and is a major reason for rejection of hearing aids. Attempts have been made by previous researchers to relate the use of hearing aids to speech perception in noise (SPIN), with an expectation of improved speech perception followed by an increased acceptance of hearing aids. Unfortunately, SPIN was not related to hearing-aid use or satisfaction. A new measure of listener reaction to background noise has been proposed. The acceptable noise level (ANL), expressed in decibels, is defined as a difference between the most comfortable listening level for speech and the highest background noise level that is acceptable when listening to and following a story. The ANL measure assumes that speech understanding in noise may not be as important as is the willingness to listen in the presence of noise. It has been established that people who accept background noise have smaller ANLs and tend to be "good" users of hearing aids. Conversely, people who cannot accept background noise have larger ANLs and may only use hearing aids occasionally or reject them altogether. Because this is a new measure, it was important to determine the reliability of the ANL over time with and without hearing aids, to determine the effect of acclimatization to hearing aids, and to compare the ANL to well-established measures such as speech perception scores collected with the SPIN test. Results from 50 listeners indicate that for both good and occasional hearing aid users, the ANL is comparable in reliability to the SPIN test and that both measures do not change with acclimatization. The ANLs and SPIN scores are unrelated. Although the SPIN scores improve with amplification, the ANLs are unaffected by amplification, suggesting that the ANL is inherent to an individual and can be established prior to hearing aid fitting as a possible predictor of hearing-aid use.     

Hearing-aid use and long-term health outcomes: Hearing handicap,mental health,social engagement,cognitive function,physical health,and mortality

Objective: To clarify the impact of hearing aids on mental health, social engagement, cognitive function, and physical health outcomes in older adults with hearing impairment. Design: We assessed hearing handicap (hearing handicap inventory for the elderly; HHIE-S), cognition (mini mental state exam, trail making, auditory verbal learning, digit-symbol substitution, verbal fluency, incidence of cognitive impairment), physical health (SF-12 physical component, basic and instrumental activities of daily living, mortality), social engagement (hours per week spent in solitary activities), and mental health (SF-12 mental component) at baseline, five years prior to baseline, and five and 11 years after baseline. Study sample: Community-dwelling older adults with hearing impairment (N = 666) from the epidemiology of hearing loss study cohort. Results: There were no significant differences between hearing-aid users and non-users in cognitive, social engagement, or mental health outcomes at any time point. Aided HHIE-S was significantly better than unaided HHIE-S. At 11 years hearing-aid users had significantly better SF-12 physical health scores (46.2 versus 41.2; p = 0.03). There was no difference in incidence of cognitive impairment or mortality. Conclusion: There was no evidence that hearing aids promote cognitive function, mental health, or social engagement. Hearing aids may reduce hearing handicap and promote better physical health.     

Difficulties experienced by hearing-aid candidates and hearing-aid users

Responses to an open-ended questionnaire were obtained from 250 hearing-aid candidates who had never worn a hearing aid and from 250 experienced hearing-aid users. The questionnaire stated 'Please make a list of the difficulties which you have as a result of your hearing loss.' The responses were divided into six major categories. The hearing-aid candidates reported more problems than the experienced users in the categories of (a) understanding speech where speechreading would normally be used (92% versus 81%), and (b) understanding speech where speechreading would normally not be used (51% versus 43%). A similar number of respondents in both groups reported problems in the categories of (c) personal difficulties (11%), (d) audiological or medical difficulties (18%), and (e) difficulties associated with environmental sounds (34%). Thirty-five per cent of the hearing-aid users reported (f) difficulties associated with their hearing aids. The most frequently reported specific difficulty in both groups was watching television (47% of the candidates and 37% of the users). Twenty-one per cent in each group reported difficulty conversing on the telephone.     

Semantic context improves speech intelligibility and reduces listening effort for listeners with hearing impairment

Objective: We investigated whether speech intelligibility and listening effort for hearing-aid users is affected by semantic context and hearing-aid setting. Design: Participants heard target sentences spoken in a reverberant background of cafeteria noise and competing speech. Participants reported each sentence verbally. Eight participants also rated listening effort after each sentence. Sentence topic was either the same as, or different from, the previous target sentence. Study sample: Twenty participants with sensorineural hearing loss were fit binaurally with Signia receiver-in-the-canal hearing aids. Participants performed the task twice: once using the hearing aid’s omnidirectional setting and once using the “Reverberant Room” setting, designed to aid listening in reverberant environments. Results: Participants achieved better speech intelligibility for same-topic than different-topic sentences, and when they used the “Reverberant Room” than the omnidirectional hearing-aid setting. Participants who rated effort showed a reliable reduction in listening effort for same-topic sentences and for the “Reverberant Room” hearing-aid setting. The improvement in speech intelligibility from semantic context (i.e. same-topic compared to different-topic sentences) was greater than the improvement gained from changing hearing-aid setting. Conclusions: These findings highlight the enormous potential of cognitive (specifically, semantic) factors for improving speech intelligibility and reducing perceived listening effort in noise for hearing-aid users.