Nebulized Saline Solution: A Multidimensional Voice Analysis

Purpose: To verify the effect of nebulization on the voice of dysphonic and non-dysphonic individuals on acoustic, perceptual-auditory, aerodynamic, electroglottographic, laryngeal parameters and on the self-perception of vocal discomfort.

Materials and methods: All the research subjects were submitted to vocal evaluation, laryngeal and voice self-perception. Then, the participants remained in vocal rest for a period of 10 minutes and the analysis mentioned above were again performed. After this first stage, the participants were submitted to the nebulization for a period of 10 minutes and the all analysis above were again performed. Descriptive analysis of the variables was carried. In the comparison of the pre- and post-nebulization groups, the Paired T-Student Test was used for variables with non-dysphonic distribution and the Wilcoxon Test for variables with asymmetric distribution. When categorical variables were evaluated (perceptual-auditory evaluation and laryngeal assessment), the Pearson's Chi-square test was used. In all analysis, a significance level of 5% was considered. The intra-rater agreement in the auditory-perceptual and perceptual-visual assessment was assessed using the AC1 statistic, using the R program. For this purpose, 20% of the voice samples and laryngeal images were replicated blindly and interpreted by the evaluators at the time evaluations.

Results: The results of this research show that non-dysphonic individuals have more positive vocal and laryngeal effects after nebulization than dysphonic ones. It is also observed that the EGG measurement was the most sensitive to the effect of nebulization, with an increase in the Closed quotient (CQ) in all groups evaluated. Regarding acoustic measurements, it is noted that the effect of nebulization in men is more evident than in women. After nebulization, there was an increase in fundamental frequency in the group of non-dysphonic women and dysphonic and non-dysphonic men. A decrease in the amplitude perturbation quotient values is observed in all groups, besides a reduction in the pitch perturbation quotient values after nebulization in non-dysphonic men groups. There was improves aerodynamic efficiency in groups of dysphonic and non-dysphonic men and in the self-perception of vocal discomfort in all groups studied after the hydration procedure. The results of this study demonstrate a significant improvement in the mucosal wave after nebulization in the groups of women and men who are not dysphonic.

Conclusion: The nebulization procedure with saline solution improves acoustic measurements, the electroglottographic closed quotient and vocal self-perception of dysphonic and non-dysphonic women and men. Nebulization increases the mucosal wave of the vocal folds in non-dysphonic women and men and improves the aerodynamic efficiency of men.