Cricothyroid Dysfunction in Unilateral Vocal Fold Paralysis Females Impairs Lexical Tone Production

Area of Science:

• Otolaryngology
• Speech and Language Pathology
• Acoustic Analysis

Background:

• Unilateral vocal fold paralysis (UVFP) affects voice production.
• The role of cricothyroid (CT) muscle dysfunction in UVFP patients' tonal language production is not well-defined.
• Mandarin, a tonal language, relies heavily on pitch variations for meaning.

Purpose of the Study:

• To investigate the impact of CT muscle dysfunction on Mandarin tonal production in UVFP patients.
• To compare voice tone characteristics between UVFP patients with and without CT muscle dysfunction.

Main Methods:

• Cross-sectional study involving 88 female UVFP patients.
• Acoustic voice analysis and laryngeal electromyography (LEMG) were performed.
• Patients produced four Mandarin tones; data analyzed for CT+ (n=17) and CT- (n=71) groups.

Main Results:

• CT+ group showed reduced pitch rise range and rate for Tone 2, and lower F0 at offset.
• CT+ group exhibited reduced pitch drop range and rate for Tone 4, and lower F0 at onset.
• Significantly lower CT muscle activity was observed in the CT+ group across all tones.

Conclusions:

• CT dysfunction limits the high-rising and high-falling tonal contours essential for Mandarin.
• This limitation in tonal expression can significantly impair communication abilities in UVFP patients.
• Highlights the importance of assessing CT muscle function in UVFP patients speaking tonal languages.