Noninvasive measurement of traveling wave velocity in the canine larynx.

Laryngologists have long recognized that assessment of the mucosal wave is an important part of laryngeal evaluation. This is the first report of a noninvasive measurement of vocal fold displacement velocity in an in vivo canine model. A newly developed calibrating endoscopic instrument capable of measuring distances on the vocal fold surface is described. Displacement velocity was determined in three dogs and compared to physiologic measures in the in vivo phonation model. The results indicate that the calculated displacement velocity is linearly proportional to traveling wave velocity and fundamental frequency. Because traveling wave velocity has been shown to reflect vocal fold stiffness, this method may advance the usefulness of stroboscopy for the study of mucosal wave abnormalities.