Trends in Amplification最新文献

Analyses are made of three problem areas in the realm of hearing disorder and its management, all of which are cogently informed by self-assessment: (a) prosthetic technology and the auditory ecology, (b) dimensions of benefit from amplification, and (c) dimensions of disability. Technology and ecology addresses the matter of "fitness for purpose" of different prosthetic schemes, moderated by people's hearing and listening environments (ecologies) and by what they bring to the task of hearing and listening. Dimensions of benefit covers what is achievable with prevailing technology, and also what people are aware of and identify as their needs. Dimensions of disability examines what has been recently learned about the range of hearing functions that need attending to in management of impaired hearing. A closing section provides a portrait of "auditory reality," whose characteristics may be better appreciated when analyzed in contrast to and comparison with "visual reality."

The international contributions of Stuart Gatehouse are reviewed in three areas: as a scientist, as an advisor to health policy makers, and as a participant in international conferences. He was able, as no other auditory scientist of his time, to bridge the gap between scientific and clinical research. His ability to apply sound scientific principles to issues of clinical importance was most apparent in his work in three main areas of his research: acclimatization to amplified speech, auditory disability and hearing aid benefit, and candidature for linear and nonlinear signal processing.

Stuart Gatehouse was an internationally renowned auditory scientist whose work on basic research, government policy, and clinical practice has directly improved the quality of life of adult hearing aid users. He addressed issues of relevance to the lives of hearing-impaired adults, especially on the impact of a hearing loss on an individual, the management of hearing loss, and the measurement of the benefits offered by hearing aids. He also influenced practice and service delivery and made major contributions to the delivery of audiological services in the United Kingdom, including chairing a report that directly led to their modernization in Scotland. This article describes his life and career.

Compression is used in hearing aids to compensate for the effects of loudness recruitment. This article describes the distinction between, and relative merits of, slow and fast compression systems. A study of Gatehouse and coworkers leads to the following conclusions: (a) The benefit from compression is greatest among individuals who experience a wide range of sound levels within short periods of time, (b) slow compression generally leads to higher listening comfort than fast compression, (c) the benefit from fast compression varies across individuals, and those with high cognitive ability are able to benefit from fast compression to take advantage of temporal dips in a background sound. It is argued that listening in the dips depends on the ability to process the temporal fine structure of sounds. It is proposed that a test of the ability to process temporal fine structure might be useful for selecting compression speed for an individual.

Large potential benefits have been suggested for an assess-and-fit approach to hearing health care, particularly using open canal fittings. However, the clinical effectiveness has not previously been evaluated, nor has the efficiency of this approach in a National Health Service setting. These two outcomes were measured in a variety of clinical settings in the United Kingdom. Twelve services in England and Wales participated, and 540 people with hearing problems, not previously referred for assessment, were included. Of these, 68% (n = 369) were suitable and had hearing aids fitted to NAL NL1 during the assess-and-fit visit using either open ear tips, or Comply ear tips. The Glasgow Hearing Aid Benefit Profile was used to compare patients fitted with open ear tips with a group of patients from the English Modernization of Hearing Aid Services evaluation, who used custom earmolds. This showed a significant improvement in outcome for those with open ear tips after allowing for age and hearing loss in the analysis. In particular, the benefits of using bilateral open ear tips were significantly larger than bilateral custom earmolds. This assess-and-fit model showed a mean service efficiency gain of about 5% to 10%. The actual gain will depend on current practice, in particular on the separate appointments used, the numbers of patients failing to attend appointments, and the numbers not accepting a hearing aid solution for their problem. There are potentially further efficiency and quality gains to be made if patients are appropriately triaged before referral.

In a complex listening situation such as a multiperson conversation, the demands on an individual's attention are considerable: There will often be many sounds occurring simultaneously, with continual changes in source and direction. A laboratory analog of this was designed to measure the benefit that helping attention (by visual cueing) would have on word identification. These words were presented unpredictably but were sometimes cued with a temporal cue or a temporal-and-spatial cue. Two groups of hearing-impaired, older-adult listeners participated, 57 unaided and 19 aided. There was a small effect of cueing: The cues gave a 2% benefit in word identification. A variety of subsidiary measures were collected, including the Test of Everyday Attention and the Speech, Spatial, & Qualities of Hearing Questionnaire, but their links with the benefits of cueing were few. The results demonstrate the difficulty of cueing attention to improve word recognition in a complex listening situation.

Binaural hearing provides advantages over monaural in several ways, particularly in difficult listening situations. For a person with bilateral hearing loss, the bilateral fitting of hearing aids thus seems like a natural choice. However, surprisingly few studies have been reported in which the additional benefit of bilateral versus unilateral hearing aid use has been investigated based on real-life experiences. Therefore, a project has been designed to address this issue and to find tools to identify people for whom the drawbacks would outweigh the advantages of bilateral fitting. A project following this design is likely to provide reliable evidence concerning differences in benefit between unilateral and bilateral fitting of hearing aids by evaluating correlations between entrance data and outcome measures and final preferences.

Changes in the sensory environment modify our sensory experience and may result in experience-related or learning-induced reorganization within the central nervous system. Hearing aids change the sensory environment by stimulating a deprived auditory system; therefore, they may be capable of inducing changes within the central auditory system. Examples of studies that have shown hearing aid induced perceptual and/or physiological changes in the adult human auditory system are discussed. Evidence in the perceptual domain is provided by studies that have investigated (a) speech perception, (b) intensity discrimination, and (c) loudness perception. Evidence in the physiological domain is provided by studies that have investigated acoustic reflex thresholds and event-related potentials. Despite the controversy in the literature concerning the rate, extent, and clinical significance of the acclimatization effect, there is irrefutable evidence that the deprived auditory system of some listeners can be modified with hearing aid experience.

Stuart Gatehouse worked in the MRC Institute of Hearing Research Scottish Section for 29 years until his untimely death in 2007. The former director records a personal appreciation but also an explanation, for those who did not know him well, of the mixture of qualities that made him an outstanding applied scientist.