Ventricular fold vibration in voice production: a high-speed imaging study with kymographic, acoustic and perceptual analyses of a voice patient and a vocally healthy subject.
Co-vibrations of the ventricular folds are a common finding in the clinical setting. It is not always obvious how much of the perceived voice change can be attributed to the presence of such vibrations. The aim of the present study was to describe laryngeal vibrations as observed by high-speed imaging in cases where ventricular fold vibrations had been observed. The findings at kymographic display of the recordings were correlated to perceptual measures and spectrographic observations. Two subjects, a 65-year-old man with chronic laryngitis and one vocally healthy man, were examined during pressed and breathy sustained phonation. Perceived roughness in the voice quality correlated to irregularities in true vocal fold vibrations as well as to irregular ventricular fold vibrations with large amplitude combined with sufficient closure. In none of the recorded sections did ventricular fold vibrations occur without simultaneous true vocal fold vibrations. Regular vibrations of the ventricular folds of the same frequency as those of the true vocal folds and with a reciprocal pattern did not contribute to any roughness in the perceived voice.