Master of Arts (MA)
Communication Sciences and Disorders
This study examined how speech rate reduction affects speech intelligibility in speakers with dysarthria associated with diverse neurological conditions. Three speakers with dysarthria were recorded reading a paragraph using conversational and reduced speech rates. The samples of both the conversational and slow rates were digitally edited to include silent pauses at the speakers’ natural breaks. The samples were then segmented into breath group utterances. Five samples with the greatest rate reductions from each speaker were used as stimuli, each presented in four rate conditions: conversational, slow, synthesized conversational, and synthesized slow. The listeners rated the intelligibility of 60 samples using direct magnitude estimation (DME), a simple scaling technique used to rate items in comparison to a standard. Though each of the speakers successfully reduced their rates, none of their intelligibility ratings improved using rate reduction. In fact, the intelligibility of two of the speakers significantly decreased when rate reduction was employed. Analysis of the acoustic vowel space showed some articulatory changes were made by the speakers. Possible reasons for the negative effects of rate reductions are explored along with clinical implications.
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Hall, Zachary, "Effect of rate reduction on speech intelligibility in individuals with dysarthria" (2013). LSU Master's Theses. 1257.