The Effect of Pacing Strategies on the Variability of Speech Movement Sequences in Dysarthria

• Published in: Journal of speech, language, and hearing research language, and hearing research, 2003-06, Vol.46 (3), p.702-710
• Main Author: McHenry, Monica A
• Format: Article
• Language: English
• Subjects: Adult; Analysis of Variance; Articulation disorders; Biological and medical sciences; Biomechanical Phenomena; Dysarthria; Dysarthria - physiopathology; Dysarthria - therapy; Female; Fundamental and applied biological sciences. Psychology; Global Approach; Humans; Intelligibility; Intonation; Lip - physiology; Male; Medical sciences; Motor performance; Movement; Neurological disorders; Neurological Impairments; Otorhinolaryngology. Stomatology; Pacing; Physical Disabilities; Rehabilitation; Reproducibility of Results; Severity of Illness Index; Speech; Speech disorders; Speech Intelligibility; Speech production; Speech Production Measurement; Speech rate; Speech Therapy - methods; Teaching Methods; Treatment Outcome; Vertebrates: nervous system and sense organs
• ISSN: 1092-4388; 1558-9102
• DOI: 10.1044/1092-4388(2003/055)

There are many potential sources of variability in speech production, particularly in individuals with dysarthria. The degree and time course of stabilization of the speech production system during recovery from a neurological insult is not constant across individuals. Another source of variability in speech production is speaking rate. Although individuals with no neurological impairments typically show increased variability at reduced speaking rates, this phenomenon has not been explored extensively in individuals with dysarthria. Because rate control strategies are commonly used in dysarthria treatment, it is of clinical importance to know if individuals with dysarthria produce less variable speech with rate reduction. Six individuals with mild dysarthria, 6 with moderate-to-severe dysarthria, and 6 matched normal controls repeated an utterance in four speaking rate conditions: habitual, fast, breaks between words, and stretched. Data were analyzed using the spatiotemporal index (STI), a composite measure of spatial and temporal variability across token repetitions. The normal controls consistently demonstrated the least variability, regardless of rate condition. Both groups with dysarthria were the least variable in the stretched condition and the most variable in the fast condition. The STI values of the group with moderate-to-severe dysarthria were significantly different from both the individuals with mild dysarthria and the normal controls. There were no significant differences between the group with mild dysarthria and the normal controls. In general, slowing the speaking rate in individuals with dysarthria reduces spatiotemporal variability; however, the effect of reduced spatiotemporal variability on intelligibility requires further investigation.