This is a summary report of the major findings of a study designed to examine the social and psychological implications of acquired deafness for adults of employment age, issued with a National Health Service hearing aid between 1970 and 1976 in the Greater London Area. Acquired deafness, long after rehabilitation, was found to cause considerable and serious personal unhappiness.

Social and Psychological Implications of Acquired Deafness for Adults of Employment Age

The linguistic properties of the FAAF test material are expounded in relation to its objectives. It is shown from reference data that there are lexical effects inherent in the use of real-word minimal pairs rather than nonsense syllables. These are word-frequency effects upon phonemes in initial position and effects of imageability upon phonemes in final position. However, those effects are not large enough to undermine the use of the FAAF as an acoustical phonetically structured material reflecting the analysis of auditory information. Normative data on a range of signal-to-noise ratios are presented. These data have helped to delimit the subsets of items that best reflect variations in performance under easy and under difficult conditions. This offers a mapping of the percentage correct from scores at one or two fixed S/N ratios required for a given level of performance and hence permits comparison with SRT(N) measures.

The four alternative auditory feature test (FAAF)--linguistic and psychometric properties of the material with normative data in noise

Tests of sentence recognition in noise constitute an essential tool for the assessment of auditory abilities that are representative of everyday listening experiences. A number of recent articles have reported on the development of such tests, documenting different approaches and methods. However, both the development and interpretation of these tests require careful consideration of many variables. This article reviews and categorizes the stimulus, presentation, subject, response, and performance variables influencing the development and interpretation of tests of sentence recognition in noise. A systematic framework is utilized to document published findings on these variables. Recommendations and guidelines, based on test performance requirements and test objectives, are provided concerning the interpretation of results and the development of new test materials.

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Sentence recognition in noise: Variables in compilation and interpretation of tests

http://www.utdallas.edu/~assmann/hcs6367/salvi02.pdf

PET imaging of the normal human auditory system: responses to speech in quiet and in background noise

20 phonetically balanced word lists comprising 25 words in each and recorded on tape by a professional announcer have been tested on 45 subjects. Analysis of the results has enabled each of the 500 words to be assigned a grade of difficulty within the range 1-35. 25 'difficult' and 25 'easy' words re-recorded from the original tapes to form two new lists have been shown to retain their same grade of difficulty. With the same lists recorded by two additional speakers, however, word order difficulty was dramatically altered. Consideration has been given to various factors likely to affect word intelligibility including phonetic construction, word familiarity and word environment. None appeared to exert any marked influence. It is concluded that the characteristics of any recorded word articulation material are determined predominantly by the speaker and the recording technique adopted and are largely independent of other factors. Given sufficient experimental data upon recorded material, words can be selected out of context and re-recorded to provide test lists with virtually any desired characteristics.

Influence of the speaker and other factors affecting speech intelligibility

The results of Free-field speech audiometry, carried out upon 30 subjects with conductive deafness and 43 subjects with ‘cochlear’ deafness have been analysed with reference to their average ‘hearing levels’ for the frequencies 500, 1000 and 2000Hz, to give approximately 10dB differences in the ‘group average hearing levels’The speech audiograms of the conductive group follow the same course as the normal curve and all attain 100% recognition In the ‘cochlear’ group with deafness in excess of 31dB it has been possible to demonstrate a systematic deterioration of speech discrimination with hearing levels The resultant correlation has practical application in (a) scales of compensation for occupational hearing loss, (b) the correction of cochlear hearing loss by means of hearing aids and (c) the use of speech audiometry in the differential diagnosis of cochlear and retrocochlear hearing loss

Speech Audiometry in Conductive and Sensorineural Hearing loss

A necessary feature of good recorded speech material is that each list should be identical in respect of graded order of difficulty. Extensive validatory tests have been carried out upon 20 M.R.C. word lists re-recorded by a professional announcer. It can be shown that by various manipulative procedures appreciable improvements may be obtained in the confidence limits of the material. In addition studies have been carried out upon the relationship between Speech Detection Threshold (S.D.T.) Speech Reception Threshold (S.R.T.) and Hearing level (H.L.) in normal hearing subjects. The surprising finding is that both S.D.T. and S.R.T. appear to be relatively independent of H.L. An analysis has been made of the words comprising the material in respect of their ease of recognition and is presented as an appendix.

J. P. Poole

Papers

Speech Audiometry in Conductive and Sensorineural Hearing loss

Improving the Reliability of Speech Audiometry

Clinical Technique in Bone Conduction Tests