The effect of semi-ocluded vocal tract exercises modified by oral high frequency oscillating apparatus on acousti̇c and aerodynamic parameters

The aims of the present study were to determine the immediate effects of a vocal loading task and to evaluate the effects of 3 different types of exercises on voice quality with objective and subjective data. A total of 32 female participants with healthy voices were included in the study. The procedures applied in the study were based on a vocal loading task performed for 10 minutes followed by 3 different therapeutic exercises: sterile water nebulization (task-1), vocal exercise with oral high-frequency oscillation apparatus (task-2), and combined sterile water nebulization and oral high-frequency oscillation apparatus exercise (task-3). The exercises were randomized and each exercise was performed for a total of 10 minutes. Statistically, Wilcoxon signed-rank test was used when two measurements were compared and Friedman test was used when more than two measurements were compared. All 3 different exercises were observed to reduce different acoustic perturbation values at the end of vocal loading. It was also observed that these exercises reduced the perturbation parameters obtained from the pre-recording. Finally, it was observed that the fundamental frequency values obtained both after vocal loading and after all exercises increased compared to the pre-recorded Fo values. The 10-minute vocal loading task had no acoustic, electroglottographic and aerodynamic effect on the pre-recorded habitual voice, but produced a perceptually increased vocal effort according to the BORG CR-10 scale results. Moreover, according to the BORG CR-10 results, only the values obtained after sterile water nebulization were still statistically higher than the pre-recorded habitual voice values. Finally, except for sterile water nebulization, the other two exercise procedures decreased the pre-recorded EGG-CQ values of the habitual voice. Sterile water nebulization, which involves only superficial hydration of the vocal fold, was able to reduce the acoustically abrupt effects of vocal loading, but failed to reduce the perception of vocal effort in the pre-recorded habitual voice and did not differentiate the movement pattern of the vocal fold. Therefore, it is suggested that adding elements of physiological voice therapy, such as VOHFO or SOVT, to the procedures used for superficial hydration of the vocal fold may further enhance the positive effect on the voice.