Effects of aging on word intelligibility and listening difficulty in various reverberant fields

Listening difficulty ratings is a new measure to evaluate speech transmission performance in public spaces. The advantage is that it can evaluate sound fields with higher speech transmission performance more accurately and sensitively than intelligibility scores. The effect of aging, or hearing level on listening difficulty ratings has not been clarified yet. In this paper, the results of the listening tests demonstrated that hearing levels above 2 kHz significantly affect both word intelligibility scores and listening difficulty ratings for the aged. For the aged, both of them can be estimated from the results for the young plus the average of hearing levels at 2 and 4 kHz. The equations for estimating the word intelligibility scores and the listening difficulty ratings for the aged are obtained from the multiple linear regression analyses. The estimated scores and ratings generally coincide with the measured scores and ratings, and the averaged difference between them is 5.2% for the word intelligibility scores and 3.8% for the listening difficulty ratings, in the range of listening tests performed in this paper.