Phonation Quotient Using Three Aerodynamic Instruments in the Disordered Voice

Abstract

The purpose of this study was to examine measures of phonation quotient (PQ) in two groups of persons with voice disorders using three different aerodynamic instruments representing low-tech and high-tech options. Prospective, repeated measures design. Two groups of patients with a diagnosis of vocal fold paralysis/paresis (n = 9) or benign vocal fold lesions (n = 8) were assessed for maximum phonation time and vital capacity obtained from three aerodynamic instruments: a hand-held analog windmill-type spirometer; a hand-held digital spirometer; and the Phonatory Aerodynamic System (PAS), Model 6600. PQ was calculated using vital capacity from each instrument along with maximum phonation time. Univariate ANOVAs were performed to test for the main effects of disorder and instrument on derived PQ. Paired samples t tests were performed post hoc to investigate any significant main effects. Pearson product-moment correlation was performed to assess measurement reliability (parallel forms) between the instruments. Statistically significant differences were found for measures of PQ as a function of disorder but not instrument type. There was not a significant interaction effect between disorder and instrument type. Strong positive correlations were present between all three instruments for measures of PQ. PQ was sensitive to differences in airflow as a function of disorder etiology (paralysis/paresis vs benign lesions). This clinical measure of laryngeal function can be used as a low-cost substitute in the absence of a pneumotachograph. These results are consistent with previous literature reporting data from adult male and female speakers with normal voice quality, and support the use of low-tech options for measurement of basic aerodynamic variables associated with voice production.