Speech recognition measures with noise suppression hearing aids using a single-subject experimental design

Hearing impairment in older adults: new concepts

OBJECTIVE

To review present information about the epidemiology, etiologies, pathogenesis, evaluation, and quality of life aspects of hearing loss and to present an approach to rehabilitation for hearing loss in older adults.

DESIGN

A survey of recent findings on the problem of hearing loss in older adults, efficacy of intervention with amplification, and new developments in intervention strategies.

CONCLUSIONS

The complex nature of hearing problems in older adults involves changes in the auditory periphery as well as in the central mechanisms for processing sound input. These changes affect the social and emotional impact of the hearing disorder. The importance of understanding the many implications of hearing loss on quality of life is emphasized. Both older adults and immediate family members need information and advice about the consequences of age-related hearing loss. The physician has a key role in helping them to overcome negative attitudes toward a hearing handicap. For most older persons, hearing aids alleviate many of the handicaps of hearing impairment. For some older persons who do not benefit adequately from conventional hearing aids, assistive listening devices may be helpful. Many old persons and their relatives are reluctant to confront the reality of hearing handicap and try to hide the fact that they need sound amplification. One important future direction is to foster acceptance of hearing loss and to support the more open use of amplification systems.

Longitudinal study of hearing aid effectiveness. I: Objective measures

This report is the first of two detailing a longitudinal follow-up of hearing aid users. Sixty-five subjects were followed for 12 months post-hearing aid fitting. Objective tests included insertion gain, the Speech Perception in Noise (SPIN) test (Kalikow, Stevens & Elliot, 1977; Bilger, Neutzel, Rabinowitz, & Rzeczkowski, 1984) and the Nonsense Syllable Test (NST) (Levitt & Resnick, 1978) presented in quiet and noise backgrounds. Initially each subject's hearing aid was fit to the revised National Acoustic Laboratories prescriptive formula (NAL-R) (Byrne & Dillon, 1986) using insertion gain measures. Use gain, measured at 6 and 12 months post-fitting, indicated that subjects generally used those prescribed values, except for subjects in the steeply sloping configuration subgroup. The NST and SPIN tests were administered at the fitting and at 1, 3, 6, and 12 months post-fitting. No change in performance, or training effect, was found for the group or for factors of experience, degree of hearing loss, configuration of hearing loss, use time, or circuit type. Failure to demonstrate a training effect may be attributed, in part, to the fact that initial speech recognition testing was done with the hearing aid volume set at the prescribed values. None of the circuits used showed performance superiority, except when comparing scores for the NST obtained in a quiet background to those obtained in a background of speech-weighted noise. In that comparison, the users of adaptive filter circuits exhibited less deterioration of performance in a noise background.