## 4 Discussion  
This study investigated the performance of AVQI and CPPS in a strictly normophonic subject group to enhance the interpretation of dysphonic voice samples and to increase the clinical utility of these measures in the assessment of overall voice quality. In 2009, [PERSON] et al. [5] developed the multiparametric tool AVQI and found a threshold score of 2.95 using receiver operating characteristics (ROC) curve analysis. This value needs to be interpreted as a cut-off score to discriminate between normophonic and dysphonic voices with a weighted sensitivity and specificity of 74% and 96%, respectively. In the present study, an upper cut-off value of 4.04 was found, which implies a very high specificity of 97.5% but low sensitivity. To our knowledge, only one other normative study on AVQI has been conducted. In 2017, [PERSON] et al. [39] performed AVQI analysis on concatenated voice samples of 123 vocally healthy Lithuanian speaking individuals and investigated the influence of age and gender. They reported a mean AVQI score of 2.32 and an upper limit value of 3.90, which approaches our findings. Similar to the present study, no significant gender effects were found. Consequently, one could suggest that AVQI is relatively unaffected by gender-based differences in vocal anatomy and physiology. In the present study, mean AVQI values were higher in subclinical subjects compared to normophonic subjects. This finding, however, did not reach significance. Furthermore, as more judges rated G as 1 (i.e., slight dysphonia), the higher mean AVQI values were observed. A significant difference was only found between the true normophonic cohort and the second subclinical dysphonia cohort. Figure 3: (**a–d**) Differences between mean AVQI and CPPS values of the normal cohort and sub-levels of subclinical slight dysphonia presented by box plots with corresponding significance. It is also interesting to compare our CPPS values to those found in other studies with normative data, also using CPPS measurement in the software Praat. [PERSON] et al. [40] performed CPPS measurements on concatenated voice samples of 530 normophonic voices and found a mean CPPS value of 11.92 (SD = 2.15). [PERSON] et al. [41] reported a mean value of CPPS of 13.9 (SD = 1.9) and 10.5 (SD = 1.2) for 40 normophonic vowel samples and speech samples, respectively. [PERSON] et al. [35] reported a mean CPPS value of 4.77 (SD = 0.97) for 87 normophonic speech samples using SpeechTool software and reported a cut-off value of 4.0 discriminating between normal and dysphonic voices with a sensitivity and specificity of 92.4% and 79% respectively, using receiver operating characteristic (ROC) curve analysis. These differences in CPPS values can be explained by different settings and methodology within and among software packages. Furthermore, comparisons with CPPS values found in the present study can only be carried out when similar settings in Praat are used (Figures 1 and 2). In the present study, specific significant gender effects were found for CPPS. Significantly higher values of CPPS\({}_{\text{vowel}}\) (t = \(-\)3.734, p \(<\) 0.001) and CPPS\({}_{\text{combination}}\) (t = \(-\)3.028, p = 0.004) were found in males and significantly higher values of CPPS\({}_{\text{sentences}}\) (t = 2.182, p = 0.032) in females (Table 5). It is known that the type of speech task causes important variability in the perceptual-auditory evaluation of voice quality. A previous study conducted by [PERSON] et al. [42] showed that the two speech tasks--i.e., sustained vowels and continuous speech--yielded significant differences in their ratings of degree of dysphonia severity (i.e., Grade). There is a tendency towards significantly higher G scores for sustained vowel samples than for continuous speech samples. The gender effect of these different types of speech tasks has however never been investigated.