Prosodic Control in Severe Dysarthria

Preserved Ability to Mark the Question-Statement Contrast

rp564{at}columbia.edu

Speakers with severe dysarthria are known to have reduced range in prosody. Consistent control within that range, however, has largely been ignored. In earlier investigations speakers with severe dysarthria were able to control pitch and duration for sustained vowel production despite reduced flexibility of control (Patel, 1998). The present experiment examined whether 8 speakers with severe dysarthria due to cerebral palsy used prosodic parameters of pitch contour and syllable duration for phrase-level productions. Speakers with dysarthria (N=8) produced 3-syllable phrases as questions and statements. Naïve listeners (N=48) classifed dysarthric productions as either questions or statements. Listeners were able to distinguish questions from statements with accuracy levels ranging from 81% to 98 %. We were also interested in studying how dysarthric speakers marked the question-statement contrast. Prosodic features of pitch contour and syllable duration were systematically removed from the original recorded vocalizations to examine the salience of these features on listener classification. Removal of pitch contour cues dramatically reduced listener accuracy scores to almost chance performance. Listeners found pitch contour cues to be informationbearing cues in dysarthric vocalizations even though the range of frequency control in these speakers may be reduced. That speakers with dysarthria were able to exert sufficient control to signal the question-statement contrast has implications for diagnostic and intervention practices aimed to optimally exploit prosodic control for enhancing communication efficiency.

KEY WORDS: dysarthria, prosody, question-statement, cerebral palsy, fundamental frequency

Submitted on September 21, 2001
Accepted on May 7, 2002

This article has been cited by other articles:

				P. J. Watson and D. Hughes The relationship of vocal loudness manipulation to prosodic f0 and durational variables in healthy adults. J Speech Lang Hear Res, June 1, 2006; 49(3): 636 - 644. [Abstract] [Full Text] [PDF]