The time course and magnitude of perceptual acclimatization to frequency responses: evidence from monaural fitting of hearing aids.

At high presentation levels, normally aided ears yield better performance for speech identification than normally unaided ears, while at low presentation levels the converse is true [S. Gatehouse, J. Acoust.

Clinical pure-tone versus three-interval forced-choice thresholds: effects of hearing level and age.

Hearing threshold levels were measured at 2 kHz using both a standard clinical procedure and a three-interval forced-choice procedure. The 240 subjects (aged 50-75 years) embraced both normal hearing and symmetrical sensorineural hearing impairment. The sample was carefully constructed to dissociate hearing threshold level from age, by oversampling the young impaired and the older normally hearing.

Costs of investigative protocols for cerebellopontine angle lesions in Scotland.

Efficient use of resources demands evaluation of current practices. This paper presents a prospective evaluation of investigative protocols for cerebellopontine angle lesions. Commonly used protocols vary greatly in their clinical effectiveness and in their costs.

The output characteristics of an implanted bone conduction prosthesis.

So far, the published guidelines for patient selection for the Audiant implanted bone conduction device have been derived from clinical trial rather than experimental study. Theoretical considerations suggest that the guidelines should be frequency specific; the need for this was investigated in a laboratory study. Two independent measures of the maximum output of the Audiant device using both the body-worn and ear-level amplifiers have been performed on two subjects.

The Chief Scientist reports ... hearing research at the Medical Research Council Institute of Hearing Research (Scottish Section).

In addition to conducting research with the Section's own resources from the MRC and the Scottish Home and Health Department, the Section stimulates collaborative clinical research with the University and Health Service Departments. This work would be unlikely to take place without the existence of the Scottish Section of the MRC Institute of Hearing Research. Its presence has contributed to the continuing recognition of the Royal Infirmary Departments as an attractive centre for postgraduate training by both British and overseas graduates, leading in time to a substantial body of clinical research in ENT.

Whole blood viscosity and red cell filterability as factors in sensorineural hearing impairment in the elderly.

Deficiencies in blood supply can lead to impairments in cochlear function. We have reported significant associations of both measures of whole blood viscosity and derived measures of red cell rigidity with hearing threshold levels in individuals with sensorineural hearing impairments. This paper describes direct measures of red cell filterability in a group balanced across the variables of hearing threshold level and age to facilitate dissociation of the effects of factors correlated with age.

Factors that influence the benefit from amplification in the elderly.

Many factors have been proposed as potential determinants of the benefit that an individual receives from wearing a hearing aid. In this study, to quantify their relative importance, 54 individuals with symmetrical sensorineural hearing impairment were presented with and without simulated hearing aid characteristics on two measures of disability that were based on identifying words in sentences. Benefit was defined as the difference between the percentage of correct scores with and without the aid characteristics switched into the audio circuit.

The role of non-auditory factors in measured and self-reported disability.

The effect of age per se on auditory disability in relation to other non-auditory factors, including personality and IQ, is unclear because of the close link with hearing threshold level. Auditory disability may be assessed in terms of either performance or self-report. It was measured using two tasks identifying words in sentences: (1) sentence identification in noise for spatially separated signal sources, and (2) identification of sensible and nonsensical sentences given at normal and artificially accelerated rates.

The contribution of central auditory factors to auditory disability.

Auditory disability increases with both hearing threshold level and age. It is often suggested that some or most of the age effect in auditory disability is underpinned by deficits in central auditory function. A sample of 240 individuals aged between 50 and 75 years was examined to provide a balance across the major variables of hearing level and age.

A pseudo free-field measure of auditory disability.

Conventional measures of auditory disability via speech identification scores are usually monaural, or occasionally, diotic. Circumstances of everyday listening usually contain stereophonic (dichotic) cues, whilst such listening situations can be tested in a free field environment they are difficult to standardize and calibrate. A procedure has been developed by recording the signals from two Zwislocki couplers in a KEMAR mannikin to produce a headphone-presented set of speech material containing the important dichotic cues present in free field listening.

Benefit from binaural hearing aids in individuals with a severe hearing impairment.

The relative benefits of binaural as opposed to monaural hearing aids were assessed by the use of a diotically presented, audiovisual speech-in-noise task in a group of bilateral, severely hearing-impaired individuals. Significantly greater benefit was gained from binaural amplification, irrespective of hearing level and degree of asymmetry. The benefit was considered to be due to central summation.

An audiovisual test of hearing disability using free-field sentences in noise.

An audiovisual test, using BKB sentences in noise, has been developed to assess hearing disability, unaided and aided with a hearing aid(s), in severely hearing-impaired individuals. After a single practice list, no significant further increases in performance were detected. The test is reproducible within and between test sessions.