Ingo R. Titze Michael R. Titze
Natl. Ctr. for Voice and Speech, Dept. of Speech Pathol. and Audiol., Univ. of Iowa, Iowa City, IA 52242
A physical model of a vocal fold was constructed with three layers: an artificial epithelium (latex), a superficial Reinke's space (water), and an immobile vocal fold body (aluminum). This vocal fold was positioned in a plexiglas airway such that the glottal aperture and the convergence angle could be varied systematically with respect to a solid boundary, which represented the opposite vocal fold in a hemilarynx configuration. Subglottal pressure was controlled with a constant pressure valving system. Phonation threshold pressure (the Hopf bifurcation in nonlinear dynamics) was measured as a function of glottal aperture and divergence angle. This pressure increases with increased aperture and convergence, as predicted by theory, but results for a divergent glottis are not as easy to interpret. [This research was supported by Grant No. P60 DC00976 from the National Institute on Deafness and Other Communication Disorders.]