Changes in Oral Vowel Sounds and Hyoid Bone Movement After Thyroidectomy

Area of Science:

• Otolaryngology
• Speech Science
• Acoustic Analysis

Background:

• Voice and speech changes are potential side effects of total thyroidectomy.
• Extralaryngeal factors like neck muscle dysfunction and scar contracture may contribute to these alterations.

Purpose of the Study:

• To investigate acoustic characteristics of oral vowels and hyoid bone movement before and after total thyroidectomy.
• To identify specific changes in vocal acoustics and laryngeal biomechanics following the procedure.

Main Methods:

• Acoustic analysis of seven vowels (Fundamental frequency [Fo], formants, vowel space area) in 29 female patients.
• Videofluoroscopic evaluation of hyoid bone movement at baseline, 7 days, and 3 months post-surgery.

Main Results:

• Significant decrease in Fo levels for seven vowels post-surgery.
• Significant changes in F1 for vowel /[e]/ and F3 for vowel /[i]/ at 3 months and 7 days, respectively.
• Decreased hyoid bone movement (Y coordinate) for vowels /[i]/ and /[e]/ observed 7 days post-surgery.

Conclusions:

• Thyroidectomy-induced neck muscle damage impacts vocal parameters (Fo, formants) and hyoid bone position.
• These quantitative findings provide a basis for voice management strategies in post-thyroidectomy patients.