A Comparison of Indirect and Direct Methods for Estimating Transglottal Airflow Rate.

OBJECTIVE

The purpose of this study was to compare indirect estimates of transglottal airflow rate using measures of phonation quotient with direct measures of mean airflow rate derived from a pneumotachograph.

STUDY

DESIGN

This study used prospective, repeated measures design.

METHODS

Nineteen male and female participants, matched for age, completed tasks for maximum phonation time and vital capacity in addition to the comfortable sustained phonation protocol of the Phonatory Aerodynamic System (PAS), Model 6600. Phonation quotient was calculated from the vital capacity and phonation time measures, whereas actual transglottal airflow was obtained from the flow waveforms recorded on the PAS system. Statistical analyses compared transglottal airflow rate measures as a function of instrument and separately as a function of gender.

RESULTS

Statistically significant differences were present only as a function of gender on airflow measures but not as a function of the instrument. There were no interaction effects present between instrument and gender.

CONCLUSIONS

Phonation quotient can be used as an estimate of transglottal airflow in the absence of a pneumotachograph-based system.