Syllabic timing in dysarthria.

A new, intensity-based method of measuring syllable duration was used to assess syllabic timing in 75 patients with dysarthria of predominantly traumatic and cerebro-vascular origin and in 30 normal subjects. The applied speech tasks included repetitions of sentences containing chains of plosive-vowel-syllables. The logarithm of the duration of the syllable carrying sentence accent proved to be particularly highly correlated with perceived speech rate. Among the potential sources of temporal variability, segmental influences and the influence of sentence stress were examined. Further, the between-sentence variation of syllable duration was assessed. The resulting measures of variability were correlated with the severity of dysarthric impairment. A strengthening of normal effects was found in the consonant-related variation, whereas intrinsic vowel effects and the influence of sentence stress were largely reduced. These results are discussed from the viewpoint of timing theories in speech and limb motor control. They are considered to provide a valuable background against which the speech impairments of specific neurologic groups can be tested.