Establishment and Analysis of False Vocal Folds Hypertrophy Model in Excised Canine Larynges.

OBJECTIVE

This study aimed to investigate the role of false vocal folds (FVFs) medialization in phonation and the acoustic impact of ventricular hypertrophy by establishing an FVF hypertrophy model.

STUDY DESIGN

A prospective in vitro experiment was carried out.

SETTING

The study was carried out using a pseudolung platform with high-speed camera in a soundproof room.

MATERIALS AND METHODS

Control, degree I, and degree II FVFs hypertrophy were simulated in 10 excised larynges via fructose injection of 0.1 mL for degree I and 0.25 mL for degree II. Mean flow rate (MFR), fundamental frequencies (F0), formants, and sound pressure level were measured with a subglottal pressure of 1.5 kPa and 2.5 kPa, respectively.

RESULTS

When the subglottal pressure was controlled at both at 1.5 kPa and at 2.5 kPa, the degree of FVF hypertrophy significantly influenced the distribution of the formants, F0, and MFR in excised canine larynges. Increasing the degree of hypertrophy was associated with a decrease in F0 and an increase in MFR. In degree II FVF hypertrophy models, the sound pressure level and the first formant were significantly higher (P < 0.05) than in normal models.

CONCLUSION

Hypertrophy of the FVFs has a significant influence on the distribution of sound energy and is associated with changes in sound quality.