Intonation and speech rate in dysarthric speech.

Ten dysarthric speakers of various etiologies, type, and severity were compared to age-matched and gender-matched nondysarthric speakers on 40 short sentences. These sentences were presented in both declarative and interrogative versions. Measures of (1) mean intonation difference (average difference in fundamental frequency between the last syllables of interrogative and declarative sentences) and (2) speech rate were obtained using the IBM Speech Viewer system. Analyses of variance were performed on the resulting measures with subject group, sentence type, and sentence sets as independent variables. Results indicate that (1) intonation values are significantly reduced in the dysarthric group as compared to those for the nondysarthric group; (2) rate varies as a function of subject group, sentence type, and sentence set. Moreover, intonation varies with severity of dysarthria, but not speech rate. These findings concur with the notion that dysarthria is a deficit in performance rather than in competence. The results are also discussed in reference to "breath-group" theory for intonation (Lieberman, 1967).