Variability Within and Across Physiological Systems in Dysarthria: A Comparison of STI and VOT.

Variability Within and Across Physiological Systems in Dysarthria: A Comparison of STI and VOT.

There are many sources of variability within the speech production system. It is not known if variability within a system is associated with variability across physiological systems. In this investigation, eight individuals with dysarthria and six individuals with no neurological disorders repeated an utterance in four speaking conditions. The spatio-temporal index (STI), a composite measure of spatial and temporal variability taken across token repetitions, was derived from the movement of the lower lip. To assess variability across the respiratory, laryngeal, velopharyngeal, and articulatory systems, voice onset time (VOT) was calculated for each participant’s least and most variable utterances, as determined by STI. The coefficient of variation (COV) of VOT was taken as a measure of variability across physiological systems. There was a significant difference in STI between low and high variability conditions across groups. There was no difference in VOT COV between the two conditions. Further, there was no relationship between VOT COV and STI. The methodological limitations of the present investigation precluded finding a relationship between variability within a single physiological system (i.e., articulatory) and variability across physiological systems (as represented by VOT COV). **********

Variability Within and Across Physiological Systems in Dysarthria: A Comparison of STI and VOT.

Variability Within and Across Physiological Systems in Dysarthria: A Comparison of STI and VOT. | | 4.5