Recognition of natural and time/intensity altered CVs by young and elderly subjects with normal hearing.

The purpose of this study was to evaluate the efficiency of three acoustic modifications derived from clear speech for improving consonant recognition by young and elderly normal-hearing subjects. Percent-correct nonsense syllable recognition was measured for four stimulus sets: unmodified stimuli; stimuli with consonant duration increased by 100%; stimuli with consonant-vowel ratio increased by 10 dB; and stimuli with both consonant duration and consonant-vowel ratio increased. Analyses of overall nonsense syllable recognition, consonant feature recognition, and consonant confusion patterns demonstrated that the consonant-vowel ratio increase modification produced better performance than the other acoustic modifications by both subject groups. However, elderly subjects exhibited poorer performance than young subjects in most conditions. These results and their implications are discussed.