Clinical study of a digital vs an analogue hearing aid.

Digital signal processing in hearing instruments has brought new perspectives to the compensation of hearing impairment and may result in alleviation of the adverse effects of hearing problems. This study compares a commercially available digital signal processing hearing aid (HA) (Senso) with a modern analogue HA with programmable fitting (Logo). The HAs tested are identical in appearance and, in spite of a different mode of operation, the study design ensured blinding of the test subjects. Outcome parameters were: improvements in speech recognition score in noise (deltaSRSN) with the HAs; overall preference for HA; overall satisfaction; and various measures of HA performance evaluated by a self-assessment questionnaire. A total of 28 experienced HA users with sensorineural hearing impairment were included and 25 completed the trial. No significant differences were found in deltaSRSN between the two HAs. Eleven subjects indicated an overall preference for the digital HA, 10 preferred the analogue HA and 4 had no preference. Concerning overall satisfaction, 8 subjects rated the digital HA superior to the analogue one, whereas 7 indicated a superior rating for the analogue HA and 10 rated the HAs equal. Acceptability of noise from traffic was the only outcome parameter which gave a significant difference between the HAs in favour of the digital HA. It is concluded that there are no significant differences in outcome between the digital and analogue signal processing HAs tested by these experienced HA-users.

Self-reported need of information, counselling and education: needs and interests of re-applicants.

An interview study was performed to establish and evaluate the need for education and counselling of hearing aid users (HA users) in order to review present procedures of information and potential referral to the educational sector. The study comprises 102 consecutively selected hearing-impaired adults (>18 years), the only inclusion criterion being experienced HA user. The interview took place immediately after the patient's latest HA fitting appointment and consisted of 24 structured and closed questions. The findings indicate that a significant proportion of HA users, especially the elderly, do not experience a need for or show an interest in further education and counselling concerning their hearing handicap. It is concluded that the present organization of services meets the demands of a majority of re-applicants.

A double-blind cross-over study of a non-linear hearing aid.

New hearing aids are usually introduced after clinical trials. These are mostly based on subjects reports, in which it is possible that the subject's judgment of the acoustic performance might be influenced by the awareness that it is a new hearing aid which is being investigated. To examine the benefit of a new non-linear amplification circuit, a double-blind cross-over study was conducted. Two 'new' hearing aids were developed; they were identical in external appearance and differed only in that one involved ordinary linear amplification while the other employed compressive amplification (the K-amp circuit). Forty-five experienced users with sensorineural hearing loss, aged 60-80 years, used each of the aids for ten weeks, in balanced order. The subjects' need for hearing aid ranged from listening to radio and television to extensive use in all kinds of demanding listening situations. The results, using a structured questionnaire concerning real-life settings, speech reception tests and subject preferences for a particular hearing aid, showed little difference between the two hearing aids. Twenty-three subjects selected the non-linear amplification circuit, 20 subjects preferred the linear hearing aid and two chose to return to their previous aid. No consistent differences between those preferring the linear circuit and those preferring compression were found. It can be concluded that this compression amplification circuit is not significantly preferred to the traditional linear hearing aid.

Hearing instruments and health technology--an evaluation.

This contribution compares a currently worn hearing instrument (i.e. R-HI) with a programmable multiband full-dynamic range compression behind-the-ear HI (i.e. T-HI), based on subject preference for HI, and, in addition, compares the preference for a linear/ non-linear amplification-mode (i.e. L-mode/C-mode). Finally, it evaluates some health technology aspects related to the devices. N = 34 experienced HI-users at a median age of 72 years (range 22-84) completed the trial, n = 5 being monaurally, and n = 29 being binaurally fitted. The trial comprises an unblinded comparative study of the R-HI and T-HI, in either C-mode or L-mode amplification, and a double-blind crossover study evaluating the C-mode versus the L-mode amplification. The results of the unblinded study showed that 94% (n = 32/34) preferred the T-HI, whereas two subjects preferred their current HI. The double-blind crossover study concerning the preference for the C-mode and L-mode, respectively, in the T-HI, showed that 72% (n = 23/32) had a significant preference for the non-linear amplification, whereas 28% (n = 9/32) preferred the linear amplification. Provided that the price of the T-HI is kept unchanged, a health technology evaluation may imply an estimate of 30 mill. DKR added costs on a national basis, which should be taken into account within the national hearing services.

Rehabilitation of hearing-impaired children: intervention and outcome.

A cohort of 72 hearing-impaired children of a median age of 9.7 years, range 4.3-13.9, born during 1980-1990 and living in the health district of Copenhagen City was examined cross-sectionally in order to evaluate the interval from identification to the initial fitting of hearing aids (HAs) and children's use of HAs. As measures of outcome, the use of HAs at 1, 6, 12 months after fitting, and at the time of data collection was assessed along with the primary language of each child. One month after the fitting, 53% of the total sample used the HAs > 8 h/day, and no significant longitudinal changes in the proportion of time-related use were found. 56% of the children stayed in the same user category during the years, while the rest either increased (25%) or decreased (19%) the use of amplification from 1 month after fitting to the time of data collection. Children with better ear hearing level (BEHL) 0.5-4 kHz between 60 and 89 dB used the HAs significantly more than those with mild or profound hearing impairments, whereas age at onset (congenital, acquired, age at onset unknown) and age at intervention were unrelated to use of amplification. 72% of the children were oral, while 25% were manual (unknown 3%), and no differences in the use of HAs were found between these two groups. A subdivision of congenitally hearing-impaired children according to BEHL 0.5-4 kHz below/above 75 dB demonstrated a significantly larger proportion of manual children in the poorer hearing group despite a significantly younger amplification age. It is concluded that age at intervention is unrelated to primary language, although the number of children precludes dependable conclusions.

Combined psychological and prosthetic management of tinnitus: a cross-sectional study of patients with severe tinnitus.

A consecutive clinical sample of 154 highly selected patients with severe problems due to tinnitus have been treated within a programme combining psychological and prosthetic approaches. The therapy works within the framework of existential psychology. The programme was evaluated by a postal questionnaire. Pre- and post-intervention comparisons of self-rated tinnitus loudness, major problems in getting to sleep and concentration showed significant improvement in all three domains. The patients greatly appreciated the programme and benefited from information on coping strategies, use of natural masking sounds and from reassurance about lack of serious pathology and prognosis. After intervention the patients were more active in sharing information about tinnitus with key persons, although the consequence in terms of greater empathy was discouraging. Two-thirds of the patients fitted with instruments as part of the programme still had their devices at follow-up. The intervention package has been evaluated as a whole, and therefore it is not possible to separate which part of the intervention each patient benefited from most. It is concluded that improvements in the lives of patients with severe problems due to tinnitus can be achieved within a management programme of this kind. The patients were divided into three severity groups according to pre-intervention impact of tinnitus upon life. Post-intervention evaluation showed that the two more afflicted groups had significantly greater benefit from the intervention in terms of self-rated tinnitus loudness and major problems in getting to sleep compared to the less afflicted group. A small subgroup of younger male political refugees was found less suitable for this type of programme. Both clinically and in the research area it is essential to specify the severity of tinnitus, and there is an urgent need to reach international consensus concerning this issue.

Hearing aid benefit related to the POGO amplification formula, evaluated from insertion gain measurements of two BTE hearing aids.

The purpose of the study was to perform clinical tests with two BTE-hearing aids (BTE-HAs) having different frequency characteristics--and to correlate the results of the clinical tests to self-assessed use and benefit. The material comprised 16 subjects (SS) (median age: 74.5 years, range: 70-83 years) with moderate, sensorineural hearing losses. Patient selection criteria were specified according to the requirements for amplification at 4 kHz. All SS were fitted with two different types of BTE-HAs which were compared by the SS in a 3-months field study. The effect of the HAs was subjectively evaluated by a questionnaire and objectively by determination of the discrimination score in background noise (DN measurements). Furthermore, the need of amplification was checked by repeated insertion gain (IG) measurements. There was no significant difference in final HA choice. The DN measurements and IG measurements (both measured at most comfortable listening level (MCL] were significantly better with one of the HAs. The conclusion is that a correlation exists between optimal discrimination score in background noise and amplification at 2 and 4 kHz. The objective findings, however, were not reflected in any of the subjective parameters.

Age-related hearing difficulties. I. Hearing impairment, disability, and handicap--a controlled study.

The study compares the audiological profile of a group of first-time applicants for hearing aids, a group of re-applicants and a group of non-complainers, aged 70-75 years (n = 71). In spite of overlap in range, a significant difference in thresholds and discrimination was found. The lip-reading capacity was well preserved in the elderly, but showed a significant correlation to the general health condition. The audiological benefit of hearing-aids did not increase with early fitting. General satisfaction with life was independent of satisfaction with hearing; two thirds of the patients were satisfied with their aids and used them regularly. The rest were dissatisfied and used them less than once a week. The aids were most systematically used to watch TV. Pure-tone average and handicap scaling were compared as guidelines for hearing-aid fitting. The most powerful tool to identify those in need of hearing-aids was handicap scaling based on interviews concerning self-assessed hearing difficulties.

Age-related hearing difficulties. II. Psychological and sociological consequences of hearing problems--a controlled study.

71 individuals aged 70-75 years, whose audiological profile has been described in part I' of the study, were subjected to an extensive psychological questionnaire to evaluate the influence of hearing impairment on the psychological and sociological profile and general behaviour. The subjects consisted of three groups: first-time applicants for hearing-aids, re-applicants, and a control group not complaining of hearing problems. Neither hearing deterioration in general, as measured by hearing handicap and communication handicap, nor noise-induced hearing impairment was correlated to social class. The general activity level and the intellectual capacity were independent of hearing level, but a significant correlation was found between activity level and intellectual capacity. Also social class was correlated to activity level and intellectual level. Thus, a highly active life was correlated to preserved intellect and higher social class. Most of the elderly regarded themselves as being active, but this did not correlate with the objective activity score. Decreased activity was not correlated to hearing problems, but rather to physical limitations, decreased number of interests, tiredness. Self-perception was not influenced by the degree of hearing handicap and a stable mood and an optimistic attitude predominated. Only 14% experienced a depressed mood, and this state seemed to be linked to deteriorated hearing.

In-the-ear hearing aids. A comparative investigation of the use of custom-made versus modular type aids.

The present investigation was performed in order to evaluate and describe the benefit of a CITE-HA and compare its use with that of a modular type ITE-HA. Thirty-five patients at a median age of 70 (range 27-84) years, were fitted with CITE-HAs. As a reference group, we selected 37 patients at a median age of 74 (range 27-85) years, fitted with various types of modular in-the-ear-HAs. Based on an extensive questionnaire and an objective evaluation using insertion gain measurements and discrimination score in background noise, it was demonstrated that hearing disabled patients--even when elderly--benefit from in-the-ear-HAs; that the discrimination score measured with CITE-HAs was lower than that with the modular in-the-ear-HA; and that custom-made in-the-ear-HAs in general offer no major advantages when compared with the modular in-the-ear-HA types. In addition it was shown that the hearing aid amplification used by the majority of patients was considerably less than the amplification described by the POGO formula.