A Cepstral Analysis of Normal and Pathologic Voice Qualities in Iranian Adults: A Comparative Study

Introduction. The use of frequency-based analysis as an accurate method of voice analysis motivated us to evaluate the voice qualities of healthy versus dysphonic Iranian people. Methods. Two hundred normal and dysphonic participants aged between 20 and 50 years in either gender were divided into four different equal groups. For the tasks, 5-second prolongation of vowel /a/ and a sample of reading text were used for the analysis. "Speech Tool" software was employed for Cepstral peak prominence (CPP) and cepstral peak prominence-smoothed (CPPS) analyses. The t test and Mann-Whitney U test were used for statistical analysis. Results. Significant differences between the dysphonic and controls were discovered based on CPP and CPPS in the reading tasks (males and females) and CPPS in the sustained vowel (males and females). Nevertheless, the two male groups showed no differences in the sustained vowel in CPP. Moreover, significantly lower CPP and CPPS were observed in the sustained vowel and reading tasks for the dysphonic females compared to the control group and either group of males, Discussion and Conclusion. In spite of the different characteristics of consonant-vowel contexts in Persian language, the results of this study suggested that both CPP and CPPS arc appropriate to differentiate between normal and dysphonic voices in connected speech and CPPS is promising for sustained phonation in Persian. The results of this research also suggested that the male group in the normal and dysphonic samples had better CPP and CPPS values,