The effect of speaking-rate manipulations on segment durations and formant frequencies in dysarthric speakers with amyotrophic lateral sclerosis

Abstract

The effect of speaking-rate manipulations on dysarthric speech is interesting from both theoretical and clinical perspectives. The purpose of the present study was to examine the influence of speaking-rate adjustments (conversational versus fast) on segment durations and vowel formant frequencies derived from sentence productions in speakers with amyotrophic lateral sclerosis (ALS), a disease that involves death of motor neurons serving the speech mechanism, with subsequent loss of muscle mass and strength. Speakers with ALS were clearly able to change their rate for the fast condition, though not in the same proportion as the control speakers. The segment durations responded to the rate manipulation in much the same way. For formant frequencies, the effect of rate was complex, but may be generally summarized as follows: F1 was affected systematically by the rate manipulation in control males, but not among the male subjects with ALS; for females in both groups, there was little effect of rate on F1. The effects of rate on F2 measures showed no clear trend, varying across vowels and groups. Results will be discussed relative to the speech production deficit in ALS and acoustic models of speech intelligibility. [Work supported by NIDCD Award DC00319.]