Prescription of gain-setting and prognosis for use and benefit of post-aural hearing aids.

Degree of hearing aid use, aid gain setting and the improvement given by the aid in a speech identification task were determined for a sample of post-aural hearing aid users. Measures of the spectral effects of gain settings received by individuals suggested that the poor frequency responses of the aids examined severely restricted the overall gain and hence the frequency range of useful gain. The outcome variables of use, gain and improvement in identification were each examined in relation to a selection of audiological predictor variables that would be easily obtained clinically. Multiple-regression analysis furnished equations accounting for a considerable proportion of the variance in gain setting and in use and for a moderate proportion of the variance in the identification improvement score. These results suggest that it is valid to predict use on an individual basis when determining the emphasis of rehabilitative programmes and it is helpful to predict gain for individuals when advising them on the gain setting to be attempted. The patterns of correlations obtained justify determining the speech detection threshold and the uncomfortable loudness level in order to predict a most comfortable level and when assessing the benefit and use of an aid.

Use and benefit of postaural aid in sensory hearing loss.

A sample of postaural hearing aid users was followed through adaptation to use of an aid over an 18-month period subsequent to issue. Minor assistance and advice was given but no intensive hearing therapy or other instruction. A miniature timing device was installed in an aid substituted for a few days to provide a check on self-reported extent of use. On both objective and self-report measures, postaural aids receive substantially greater use than the body-worn aids in comparable previous investigations, about half the aids being used over 4 hours per day. Word-identification of free-field listening in aided and unaided conditions showed advantages of 10% or more in only 45% of those tested, yet questionnaire responses suggested reliable subjective benefits in specific listening situations. The results justify taking not only measures of speech identification improvement but also questionnaire measures and measures of time of use in field trials when evaluating overall effectiveness of aid provision.