ALS and HD Dysarthria:  Speech Intelligibility from the Everyday Listener Perspective

E Klasner, K Yorkston


The purpose of this study was to examine the barriers and strategies that listeners

endorse as they attempt to understand specific types of dysarthric speech. An earlier focus group study examined everyday listener experiences as they attempted to understand ALS and HD dysarthria (Klasner & Yorkston, 2000). The current study conducted a content analysis using the information from the focus group study. Based on this analysis, two scales (one for barriers and one for strategies) each containing 24 items were developed. These scales were presented to 37 everyday listeners who rated ALS and HD speech samples on a four-point equal interval scale. Results indicated that barriers to intelligibility vary as a function of the dysarthria type. Listeners indicated stronger endorsement for segmental, linguistic, and cognitive barriers for the ALS sentences as compared to the HD sentences. Strategies for listening also vary as a function of dysarthria type. The level of strategy endorsement was consistently high for both dysarthria types. Results support the early perceptual descriptions of dysarthria (Darley, Aronson, & Brown, 1975) in that listeners distinguished various types of dysarthria based on barriers to intelligibility.  In addition, results indicate that both bottom-up (phoneme-based) and top-down (linguistically based) processing are endorsed as strategies to understand dysarthric speech production.