Relationship between transglottal pressure and fundamental frequency of phonation--study using a rubber model.

The relationship between the change in fundamental frequency of phonation (F0) per unit change of transglottal pressure (dF/dP) was studied using a rubber model of the vocal folds that allows the stiffness and elongation of the vibrating part to be varied flexibly. Changes in elongation and stiffness successfully reproduced the negative relationship between dF/dP and F0 at low F0 seen in humans. The thyroarytenoid muscle appears to work concomitantly with the cricothyroid (CT) muscle to regulate F0, raising F0 by increasing the stiffness of the vibrating part at low F0, that is, when the CT muscle is relaxed.