A method for assessing the regional vibratory pattern of vocal folds by analysing the video recording of stroboscopy

Stroboscopy and kymography have been used to examine the motional abnormali ty of vocal folds and to visualise their regional vibratory pattern, In a p revious study (Laryngoscope, 1999), we introduced the conceptual idea of vi deostrobokymography, in which we applied the concept of kymography on the p rerecorded video images using stroboscopy, and showed its possible clinical application to various disorders in vocal folds. However, a more detailed description about the software and the mathematical formulation used in thi s system is needed for the reproduction of similar systems. The composition of hardwares, user-interface and detail procedures including mathematical equations in videostrobokymography software is presented in this study. As an initial clinical trial, videostrobokymography was applied to the preoper ative and postoperative videostroboscopic images of 75 patients with Reinke 's edema. On preoperative examination, videostrobokymograms showed irregula r pattern of mucosal wave and, in some patients, a relatively constant glot tic gap during phonation. After the operation, the voice quality of all pat ients was improved in acoustic and aerodynamic assessments, and videostrobo kymography showed clearly improved mucosal waves (change in open quotient: mean +/- SD = 0.11 +/- 0.05).