Receptive Vocabulary, Cognitive Flexibility, and Inhibitory Control Differentially Predict Older and Younger Adults' Success Perceiving Speech by Talkers With Dysarthria.

Purpose: Previous research has demonstrated equivocal findings related to the effect of listener age on intelligibility ratings of dysarthric speech. The aim of the present study was to investigate the mechanisms that support younger and older adults' perception of speech by talkers with dysarthria.

Method: Younger and older adults identified words in phrases produced by talkers with dysarthria. Listeners also completed assessments on peripheral hearing, receptive vocabulary, and executive control functions.

Results: Older and younger adults did not differ in their ability to perceive speech by talkers with dysarthria. Younger adults' success in identifying words produced by talkers with dysarthria was associated only with their hearing acuity. In contrast, older adults showed effects of working memory and cognitive flexibility and interactions between hearing acuity and receptive vocabulary and between hearing acuity and inhibitory control.

Conclusions: Although older and younger adults had equivalent performance identifying words produced by talkers with dysarthria, older adults appear to utilize more cognitive support to identify those words.