The ability of noninvasive methods to detect and quantify laryngeal obstruction.

The ability of the noninvasive methods forced oscillation technique (Rosc), spirometry and flow-volume curves to detect and quantify laryngeal obstruction, using assessment of orolaryngeal (upper) airway resistance (Rol) as reference, was compared in 55 patients with various laryngeal diseases. Statistical analysis was performed by means of sensitivity/specificity, simple regression, stepwise regression and stepwise logistic regression. The results showed that the ability to detect a laryngeal obstruction was acceptable and that Rosc-Insp, peak inspiratory flow (PIF) and forced inspiratory volume in one second (FIV1) seemed to be the best variables for detection of a laryngeal obstruction. None of the studied noninvasive methods appeared to be adequate for quantification of laryngeal obstruction.