Approach to the Dynamics of the Vocal Cords During the Exploration With Flexible Laryngeal Stroboscopy

The mucosal wave (MW) is fundamental to assessing vocal fold function, with laryngeal stroboscopy (LS) serving as a pivotal tool in its evaluation. However, technical factors associated with LS may alter the basal oscillatory dynamics of the free edges (FEs), which may bias the interpretation of results. This study aimed to analyze the dynamics of FEs, particularly MW, from the correlates extracted using a voice signal analysis method during LS, comparing it with habitual phonation without LS. Additionally, it was determined if this method can complement LS.

This descriptive study analyzed voice recordings from a sample of 137 adult subjects categorized into three groups with different conditions in their vocal folds. Voice recordings were processed using the Voice OnlineLab VCS tool. All participants had their speech signal recorded at natural pitch and volume in two situations: phonation without LS and phonation during LS. We studied the parameters: F0, tension index, glottal gap size, and MW index, closed/open phases. Statistical analysis was conducted based on the distribution values and mean differences according to the phonation situation, group, and gender. Pearson's correlation coefficient was employed to establish relationships between parameters, and Student's t-test was used to identify differences and test hypotheses.

During LS, mean F0 values increased significantly. In addition, variations were observed in the correlates that reflected the degree of tension, contact type, and the resulting MW. Furthermore, distinct compensatory patterns were identified between male and female participants.

The findings indicate important changes in patients' phonatory gestures during LS. These alterations may bias clinicians' assessments of FEs oscillatory dynamics. Therefore, practitioners using LS in clinical practice should consider these findings.

Level 2.