The effect of listener age on the recognition of dysarthric speech

Abstract

A growing number of studies have attempted to address the cognitive–linguistic source of intelligibility deficits in dysarthria. These have focused predominantly on the ability of young adults with normal hearing to decipher dysarthric speech. However, dysarthria is commonly associated with aging; older listeners often form primary communication partners. It is also known that older adults exhibit difficulty understanding speech that has been temporally or spectrally degraded. It follows that the spectral and temporal degradations present in dysarthric speech may pose a greater perceptual challenge for older, as opposed to younger, listeners. Twenty younger listeners (mean age = 20 yr) and 15 older listeners with good hearing for their age (mean age = 65 yr) transcribed the speech of individuals with moderate hypokinetic dysarthria. Percent words correct (intelligibility) was calculated and underlying error patterns at the suprasegmental and segmental levels of processing were examined. While the younger and older listener groups achieved similar intelligibility scores, the younger group showed greater reliance on syllabic strength cues to inform word boundary decisions. Similar levels of attention to segmental cues were observed across both groups. These results suggest that the recognition of dysarthric speech may be comparable across younger and older listeners.