Laryngostroboscopy and glottic dysrhythmia's.

Computer simulation of stroboscopic pictures of vocal folds with normal, regular, oscillations on the one hand, and of well-defined situations of glottic dysrhythmia's on the other hand, indicates clearly the limitations of the method, due to the irregularities of both frequency and amplitude of vocal fold oscillations. Yet, interesting propaedeutical signs suggest some kinds or ranges of glottic dysrhythmia, and allow a rough estimation of jitter and shimmer, both to be considered as fundamental physiopathological parameters.