Prosodic control in severe dysarthria: preserved ability to mark the question-statement contrast

Area of Science:

• Speech-language pathology
• Neurology
• Linguistics

Background:

• Individuals with severe dysarthria often exhibit reduced prosodic range.
• Previous research indicated control over pitch and duration for sustained vowels.
• Consistent prosodic control in dysarthria for phrase-level speech remains under-explored.

Purpose of the Study:

• To investigate if speakers with severe dysarthria utilize pitch contour and syllable duration for phrase-level productions.
• To determine the effectiveness of prosodic cues in signaling question-statement distinctions in dysarthric speech.
• To examine the salience of pitch contour and syllable duration in listener classification of dysarthric speech.

Main Methods:

• Eight speakers with severe dysarthria produced 3-syllable phrases as questions and statements.
• Forty-eight naïve listeners classified the productions.
• Prosodic features (pitch contour, syllable duration) were systematically removed to assess their impact on classification accuracy.

Main Results:

• Listeners accurately distinguished questions from statements (81%-98% accuracy).
• Removal of pitch contour cues significantly reduced listener accuracy to near chance levels.
• Pitch contour was identified as a crucial information-bearing cue for listeners.

Conclusions:

• Speakers with severe dysarthria can effectively use pitch contour and syllable duration to signal linguistic contrasts.
• Pitch contour plays a vital role in the intelligibility of dysarthric speech.
• Findings support the exploitation of prosodic control in diagnostic and intervention strategies for dysarthria to improve communication.