Abstract
We examined the variation of the phonation style from the viewpoint of laryngeal stroboscopy. We measured the open phase time and the total phase time of one cycle of phonation. We calculated the percentage of the open phase (opening quotient, OQ). The OQ was shown to be about 0.5-0.8 and with some reaching 1.0. As the OQ value increased, t he PPQ and the APQ both tended to worsen. I therefore consider a reasonable value for the OQ to be 0.5-0.8.
