Clinical Study of Hearing Instruments: A Cross-sectional Longitudinal Audit Based on Consumer Experiences:Estudio clinico de auxiliares auditivos: Revision transversal de revisión basado en las experiencias del consumidor

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

OBJECTIVE

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

DATA SOURCES

Articles were identified through systematic searches in PubMed/MEDLINE, The University of Nottingham Online Catalogue, Web of Science and through reference checking.

STUDY ELIGIBILITY CRITERIA

(1) participants aged fifty years or over with sensori-neural hearing loss, (2) provision of an air conduction hearing aid, (3) inclusion of hearing aid usage measure(s) and (4) published between 1999 and 2011.

RESULTS

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

CONCLUSIONS

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

Survey on hearing aid outcome in Switzerland: associations with type of fitting (bilateral/unilateral), level of hearing aid signal processing, and hearing loss

The present investigation further analysed results of a previously reported survey with a large sample of hearing aid owners (Bertoli et al, 2009) to determine the individual and technological factors related to hearing aid outcome. In particular the associations of hearing loss, level of signal processing, and fitting type (bilateral versus unilateral fitting) with hearing aid use, satisfaction with and management of the aid were evaluated. A sub-group with symmetrical hearing loss was analysed (n = 6027). Regular use was more frequent in bilateral users and in owners of devices with more complex signal processing, but the strongest determinant of regular use was severity of hearing loss. Satisfaction was higher in the group wearing simple devices, while fitting type and degree of hearing loss had no influence on satisfaction rates. Moderate and severe hearing loss was associated more frequently with poor management of the aid than mild hearing loss. It was concluded that bilateral amplification and advanced signal processing features may contribute to successful hearing aid fitting, but the resulting differences must be considered to be relatively small.

Clinical trial of a low-cost, solar-powered hearing aid

OBJECTIVE

In July 2001 the World Health Organization (WHO) launched their "Guidelines for hearing aids and services for developing countries". The objective of this study was to evaluate the clinical outcome of an analogue, low-cost, behind-the-ear hearing aid (BTE-HA) that met the minimum technical requirements outlined by the WHO.

MATERIAL AND METHODS

A total of 25 subjects (17 males, 8 females; median age 74 years; range 50-86 years) were recruited among patients referred for audiological evaluation who consented to participate in the trial. All subjects had a hearing loss of < or = 60 dB HL at 2 kHz, were mobile and mentally unimpaired; 13 were experienced users of HAs, 3 suffered from mixed conductive/sensorineural hearing impairment (HI) and the remainder had pure sensorineural HI. Based on pure-tone, speech and impedance audiometry the BTE-HAs were fitted, using the National Acoustic Laboratories-R (NAL-R) prescription rule, 21 binaurally and 4 monaurally. All fittings were validated by insertion gain measurements, and the immediate benefit was measured by means of the speech recognition score in background noise (SRSN; signal:noise ratio = 10 dB) without and with the HA. After a 6-week trial period a structured interview based on the International Outcome Inventory for Hearing Aids (IOI-HAs) was performed.

RESULTS

The results showed that the amplification of the HA deviated significantly from the NAL-R target at all frequencies, giving significantly more amplification at 500 and 1000 Hz despite maximum bass-cut, whenever relevant, and significantly less amplification as required at 2, 3 and 4 kHz. The median SRSN without HA was 48% (range 0-96%), which improved significantly to 80% (range 24-100%) with HA. The median individual difference in SRSN without and with HA was 20% (range 0-72%). The total IOI-HA score with the test HA was 4.1 (range 2.6-4.6), showing that it offered subjectively high satisfaction and reduction in limitations of activity.

CONCLUSIONS

The low-cost HA: (i) provides benefit to the hearing-impaired person; (ii) offers poor amplification in the high frequencies; and (iii) gives subjective satisfaction similar to that for modern available HAs.

The hearing aid revolution: fact or fiction?

OBJECTIVE

To present the experiences of consumers with traditional hearing aids (T-HAs) and digital signal processing hearing aids (DSP-HAs) during the period 1999-2001, based on data obtained from an ongoing quality assurance programme.

MATERIAL AND METHODS

A questionnaire is mailed to subjects fitted with HAs 3-4 months after the fitting, and includes questions concerning satisfaction with the HA, frequency of use of the HA, ability to manipulate the HA, satisfaction with the overall services of the department and need (if any) for additional appointments.

RESULTS

The response rate was 69.5%, and thus information was obtained from 14 325 subjects (44.9% male, 55.1% female; median age 72 years; range 18-97 years). Of the respondents, 7,983 (55.7%) had been provided with T-HAs and 6,342 (44.3%) with DSP-HAs. The results of the questionnaire were as follows: 71.4% of those fitted with a T-HA were very satisfied/satisfied with it, compared to 68.1% with a DSP-HA (p < 0.05); 91.6% and 89.1%, respectively used their HA daily/weekly (p < 0.05); 80.5% and 82.2%, respectively, were able to manipulate their HA; 96.2% and 97.3%, respectively were satisfied with the overall services of the department; and 32.5% and 48.5%, respectively, indicated a need for an additional appointment (p < 0.05). A comparison between high- and low-cost DSP-HAs showed that 68.4% and 68.2%, respectively were very satisfied/satisfied with their HA (p = NS).

CONCLUSIONS

According to consumers the "HA revolution" has failed to materialize; the significantly higher proportion of subjects with DSP-HAs who need an additional appointment represents a heavy burden on the hearing health services. The lack of a difference between the benefits obtained with low- and high-cost DSP-HAs emphasizes the need for appropriately designed and performed trials before new HA technology is launched.