Longitudinal study of hearing aid effectiveness. II: Subjective measures.

This report is the second of two detailing a longitudinal follow-up of hearing aid users. The experimental group (N = 65) was followed closely for a 12-month period after obtaining amplification. Factors of degree of hearing loss, configuration of hearing loss, previous experience with hearing aids, daily use time, and circuit type were defined. Subjective tests included the "Understanding Speech" subsection of the Hearing Performance Inventory (HPI) (Giolas, Owens, Lamb, & Schubert, 1979; Lamb, Owens, & Schubert, 1983), an expectations checklist, a qualitative judgment task, and a satisfaction questionnaire that included items of use time, battery life, and main reason for satisfaction rating. Only those items of the HPI describing fairly quiet backgrounds showed significant change (improvement) over the year. The expectation checklist showed a mean reduction in score indicative of performance exceeding expectations. The qualitative judgment task did not significantly differentiate among the circuits used, although the linear circuit was judged as having better sound quality than those circuits considered to be noise-reduction. Correlations with the objective tests reported previously in Part I suggest a weak relationship between speech recognition performance and self-assessment of communication performance. Questions of the validity of subjective measures, the best time frame for obtaining outcome measures, and the usefulness of group data are addressed.