Reliability and validity of judgments of sound quality in elderly hearing aid wearers.

OBJECTIVE The aim of the present study was to evaluate a particular sound-quality rating procedure, referred to here as the Judgments of Sound Quality (JSQ) test, for potential use as an outcome measure with elderly hearing aid wearers. The validity and reliability of the JSQ as an outcome measure were determined for unaided and aided listening conditions. DESIGN A repeated-measures design was employed with two primary independent variables, each with two values: 1) aided condition (aided versus unaided listening); and 2) trial (test versus retest). Sixteen elderly, hearing-impaired hearing aid users participated in the study. The participants provided ratings on eight dimensions of sound quality (softness, brightness, clarity, fullness, nearness, loudness, spaciousness, and total impression) under four stimulus conditions (speech at 65 dB SPL with a +8 dB signal-to-noise ratio, speech at 65 dB SPL in quiet, music at 90 dB SPL, and music at 75 dB SPL). Test and retest ratings were obtained in both unaided and aided conditions. RESULTS No significant differences were found between median test and retest scores on the JSQ. The median ratings for each sound-quality dimension were found to have moderate test-retest reliability, with test-retest correlations (r) ranging from 0.20 to 0.73 (median r value = 0.58) for the unaided listening condition, and from 0.23 to 0.85 (median r value = 0.51) for the aided listening condition. Test validity was established through significant differences in JSQ ratings for various stimulus pairs (e.g., speech in quiet versus speech in noise). In addition, significant differences were observed between unaided and aided ratings for the dimensions of clarity, nearness, loudness, and total impression with aided JSQ ratings approaching normative "ideal" values established previously. CONCLUSIONS The JSQ appears to be a potentially useful measure of hearing aid outcome, especially when using group data to document the benefits of amplification. Additional efforts should be directed at improving the reliability of the JSQ, however, before application to hearing aid wearers on an individual basis.