[Analysis of pathological vocal fold vibrations using high-speed digital imaging].

There have been various methods devised to monitor vocal fold vibration. Stroboscopy provides clinically-celevant information concerning pathology of the vocal folds. However, slow motion observation is based on the regularity of the vibration, and this ignores the role of irregularity of the vocal fold vibration in pathological cases. In order to know more about the nature of the vocal fold vibratory pattern, it is essential to monitor the vibration on a cycle by cycle basis. We analysed vocal fold vibrations of 22 pathological larynges using a computer-assisted high-speed digital imaging technique. Observed items included symmetry, regularity, phase difference, glottal closure, amplitude, mucosal wave and periodicity difference. Vibratory patterns were classified by location of lesion, severity of disease, expiratory pressure and laryngeal modulation. Analyses of pathological vocal fold vibrations using high-speed digital imaging techniques are providing the theoretical support for voice therapy and elucidating the causes of hoarseness.