Modeling vocal fold vibrations in case of unilateral vocal fold paralysis

Hoarseness in consequence of vocal fold palsies is mainly due to irregular vocal fold vibrations. With the help of digital high speed cameras it is possible to observe vocal fold vibrations in real-time. By comparing vibratory patterns as observed in high speed recordings with those of a biomechanical model a qualitativ estimation of physiological parameters is possible. In case of one-sided vocal fold palsies the changed muscle tension and vibrating mass have to be taken into consideration as well as an increased vocal fold distance. In this work a group of ten subjects, four females and six males with one-sided vocal fold palsies were examined. For all subjects a substantial asymmetric vocal fold tension was observed. Due to energy loss because of insufficient closing of the vocal folds the lung pressure was increased.