Age-related changes in monosyllabic word recognition performance when audibility is held constant.

Monosyllabic word recognition was studied in 140 subjects between the ages of 20 and 90 years. The subjects were tested under a condition of fixed audibility that was achieved by presenting bandpass-filtered Northwestern University Auditory Test No. 6 (NU-6) word lists at a constant signal-to-noise ratio and limiting threshold losses at the speech frequencies to 25 dB HL. The results indicated the following: (1) Performance did not vary appreciably with age, except among subjects over 70 years. Subjects from 70 to 80 years produced modestly reduced scores (significantly below only the 30-year-old group). Those over 80 years produced significantly lower scores (than all other groups). (2) There were no significant differences in learning or test-retest reliability associated with age. (3) The performance of the oldest subjects could not be explained by differences in speech audibility. Based on these results, a strategy is proposed for correcting predicted word recognition scores for the effects of age.