Variability characteristics of segment and ratio measures of timing in normal and neurogenically disordered speakers

Abstract

The variance of speech timing measures has been used by a variety of investigators as in index of speech motor control. Children tend to have larger variances than adults for segment durations as do some adult dysarthrics compared to neurologically intact adults. The implication is that the larger variances reflect functional immaturity and deficits in the speech mechanisms of children and neurogenically involved adults, respectively. The present report deals with variance characteristics of segment and ratio measures of timing in normal and dysarthric speakers. Two interesting results are (1) fast speaking rate increases the variability of temporal ratios in all normal subjects, and in some dysarthric subjects, and (2) increased utterance length is associated with increased timing variability in spastic dysarthrics. These results are discussed relative to organizational and biomechanical differences between conversational and fast speaking rates, and as they may apply to models of dysarthria. [Work supported by NIH.]