# Acoustic, Myoelectric, and Aerodynamic Parameters of
## 4 Discussion
\begin{table}
\begin{tabular}{l c c c c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Author**} & \multicolumn{13}{c}{**STROBE Checklist Items for Study Results and Discussion**} \\ \cline{2-13}  & **13a** & **13b** & **13c** & **14a** & **14b** & **14c** & **15** & **16a** & **16b** & **16c** & **17** & **18** & **19** & **20** & **21** & **22** \\ \hline [PERSON] et al., 2010 & N & N & N & N & N & N & - & Y & Y & - & N & N & Y & N & Y & N & N \\ [PERSON] et al., 2015 & N & N & N & N & N & - & Y & Y & - & N & N & Y & Y & Y & Y & Y \\ [PERSON] \& [PERSON] et al., 2016 & N & N & N & N & N & - & Y & Y & - & N & N & Y & Y & Y & Y \\ [PERSON] et al., 2019 & N & N & N & N & N & - & Y & Y & - & N & N & Y & Y & Y & Y \\ [PERSON] et al., 2018 & N & N & N & N & - & Y & Y & - & N & N & Y & Y & Y & Y & Y \\ [PERSON] et al., 2011 & N & N & N & N & N & - & Y & Y & - & N & N & Y & Y & Y & Y & Y \\ [PERSON] et al., 2001 & N & N & N & N & - & Y & Y & - & N & Y & Y & Y & Y & Y & Y \\ [PERSON] et al., 2017 & N & N & N & N & N & - & Y & Y & - & N & Y & Y & Y & Y & Y \\ [PERSON] et al., 2017 & Y & Y & Y & N & - & Y & Y & - & N & Y & Y & Y & Y & Y & Y \\ [PERSON] \& [PERSON] et al., 2006 & N & N & N & N & - & Y & Y & - & N & N & Y & Y & Y & Y \\ [PERSON] et al., 2006 & N & N & N & N & - & Y & Y & - & N & N & Y & Y & Y & Y \\ [PERSON] et al., 2011 & N & N & N & N & - & Y & Y & - & N & N & Y & N & Y & Y & Y \\ [PERSON] et al., 2018 & N & N & N & N & - & Y & Y & - & N & N & Y & Y & Y & Y \\ [PERSON] et al., 2014 & N & N & N & N & - & Y & Y & - & N & N & Y & Y & Y & Y & Y \\ [PERSON] et al., 2004 & N & N & N & N & - & Y & Y & - & N & N & Y & Y & Y & Y & Y \\ [PERSON] et al., 2012 & N & N & N & N & N & - & Y & Y & Y & - & N & N & Y & Y & Y & Y \\ \hline \hline \end{tabular}  
Y: reported (yes), N: not reported (no), \(\cdot\): non-applicable.  
\end{table} 
Table 7: Quality assessment for observational studies: results and discussion. The voice evaluation techniques assessed in the different included studies are highly heterogeneous. In 10 of the studies [12; 15; 16; 20; 21; 23; 24; 25; 28] only acoustic parameters were registered, two included only aerodynamic parameters [13; 22], and in seven [14; 15; 16; 17; 18; 26; 27; 29; 30] both parameters were recorded. Only one study assessed the acoustic parameters together with the myoelectric activity [19]. The most commonly analyzed acoustic parameters were the fundamental frequency [14; 15; 16; 19; 20; 21; 23; 24; 25; 29; 30], the intensity [14; 19; 21; 24; 25; 26; 28; 30], the perturbation parameters of the frequency (jitter) [12; 14; 15; 16; 17; 18; 20; 23; 24; 28], the perturbation parameters of the intensity (shimmer) [12; 14; 15; 16; 17; 18; 20; 23; 24; 27; 28], and the glottic noise (HNR, NHR, SNR... ) [12; 14; 16; 17; 23; 24; 27]. In all of the included works, the phonatory tasks performed to evaluate the vocal register were indicated, except in one study [27]. The most commonly used was the emission of a sustained vowel /a/ at a comfortable frequency and intensity, although in some cases the minimum and maximum intensity possible was also requested. Other types of phonatory tasks that were carried out were: counting numbers (from 20 to 30) [19], repeating words [17], phrases [13; 14; 17; 29], spontaneous conversation [17] and reading aloud [15]. In two works [19; 28], the sustained vowel /\(\varepsilon\)/ was requested instead of /a/. Most of the studies [12; 13; 14; 15; 16; 18; 21; 23; 24; 25; 26; 28; 29] reported on the characteristics of the space in which the samples were collected, these being silent or quiet rooms and soundproof rooms or cabins. However, only three of the analyzed studies specified the noise level in the room [14; 21; 28]. Regarding the results of the included studies in terms of acoustic parameters, the vocal disturbance parameters (jitter, shimmer, HNR, etc.)