Experimental validation of direct and inverse glottal flow models for unsteady flow conditions

The pressure drop along the glottal constriction drives vocal folds self-sustained oscillations during phonation. Physical modeling of phonation is classically assessed with the glottal geometry and the subglottal pressure as known input parameters. Several studies including in-vitro validation show that simplified one-dimensional flow models allow predictions of the flow characteristics to a fair extent. Application of physical modeling to study phonation abnormalities and pathologies requires input parameters which can be related to in-vivo measurable quantities commonly corresponding to the physical model output parameters. The current paper considers the inversion of some popular simplified flow models in order to estimate the subglottal pressure, the glottal constriction area or the flow model parameters under unsteady flow conditions. The theoretical predictions are tested against in-vitro measurements.