Measurements of mucosal wave propagation and vertical phase difference in vocal fold vibration.

Abstract

Examination of surface wave properties in the vocal fold mucosa is becoming an important part of assessment of vocal function. A key wave property is propagation velocity, which determines the phase delay between upper and lower margins of the vocal folds. Excised canine larynges were used in this study to measure this phase delay, and therewith propagation velocity. The motion of two fleshpoints was tracked stroboscopically. Differential displacements between the fleshpoints were matched to displacements of a model. A least‐squared fit of the data to the model provided the numerical values of propagation velocity, which varied from 0.5 m/s to about 2.0 m/s, depending on fundamental frequency. The corresponding phase delay along the medial surface of the vocal folds varied from about 60°/mm to 30°/mm. [Work supported by NIDCD, Grant No. P60‐DC0976.]