ABSTRACT
A 10-year study was conducted in which 282 adults in age decades of 20 through 80 were tested in a comprehensive battery of tasks requiring the perception of speech under a variety of conditions in which the speech signal was degraded. The original results were plotted to reveal the differences in performance of the population samples of each decade. In follow-up studies, after 3 years and again after 7 years, samples of the original subject population were retested. The results of the first, stratified sampling and of the longitudinal studies are compared. The two most apparent trends are: (1) the perception of degraded (distorted and competed) speech undergoes a noticeable decline beginning with the 5th decade of life, and (2) the decline is sharply steeper in the 7th decade.
