Examination of air usage during phonation: Correlations among test parameters

Correlations among parameters indicating air usage during phonation were investigated in 60 normal subjects and 1,545 voice patients. The parameters examined were maximum phonation time (MPT), mean air flow rate for maximum sustained phonation (MFRm), mean air flow rate for comfortable phonation (MFRc), and phonation quotient (PQ). In normal subjects, correlations among MPT, MFRm, and PQ were high, but those between MFRc and the others were moderate. In cases of paralysis and hypofunctional dysphonia, all correlations between the four parameters were high. In the cases of polyp, nodule, epithelial hyperplasia, glottic carcinoma, and hyperfunctional dysphonia, the correlation between MPT and MFRc was moderate or not significant. The low correlation between these parameters was associated with the variations in flow rate differences between maximum and comfortable phonations. The results suggest that measurement of all four parameters is not necessary in routine tests and that MPT and MFRc should be measured in most voice patients.     

Consistency of acoustic and aerodynamic measures of voice production over 28 days under various testing conditions

The value of any measure of voice production is dependent on its repeatability over time. The purpose of the present study was to determine the consistency of selected acoustic and aerodynamic measures of voice production over 28 days, under various test/retest conditions. Three groups of healthy young adult females sustained three vowels at comfortable, high, and low pitch levels. Subjects in Group 1 chose their own intensity levels, but matched the fundamental frequencies produced at Test 1 during Test 2. Group 2 controlled intensity levels during both tests, but fundamental frequency was free to vary. Group 3 controlled both intensity and fundamental frequency. Measures of fundamental frequency, jitter, maximum phonation time, phonation volume, and flow rate were compared. Subjects who matched both fundamental frequency and intensity showed repeatable, consistent results for all measures during both tests. Controlling intensity but not fundamental frequency resulted in statistically significant differences in fundamental frequency at comfortable and high pitches, but there was minimal effect on other variables. Controlling fundamental frequency but not intensity led to the most inconsistency between tests, affecting both acoustic and aerodynamic measures. Results underscore the need to control the conditions under which measures are obtained.