The Effect of Superficial Hydration, With or Without Systemic Hydration, on Voice Quality in Future Female Professional Singers

Objective: The aim of this study was to describe the effect of superficial hydration, with or without systemic hydration, on voice quality in future female professional singers by assessing acoustic and perceptual parameters of voice production as well as symptoms of vocal fatigue. Study Design: This is an experimental design study. Methods: A study was performed on a sample of 24 female voice majors to ascertain the effect of superficial hydration, with or without systemic hydration, on acoustic parameters and perception of vocal fatigue. The study replicated a prior study by van Wyk et al (2016) with some modifications; we looked at the effect of both systemic and superficial hydration independently and together on voice quality and vocal fatigue. Acoustic measurements including GRBASI, jitter, shimmer, F₀ MPT, frequency min and max, intensity min and max, and dysphonia severity index were measured along with perceived vocal fatigue using the Vocal Fatigue Index. Results: A statistically significant increase in MPT values were obtained when comparing pre- and post-test results of the hypo hydrated (P = 0.015) and superficial hydration condition (P = 0.004). A significant increase in frequency min (Hz) within the hypo hydrated condition was also observed (P = 0.019). A significant increase was observed in the intensity min (dB) (P = 0.010) and F₀ min (Hz) (P = 0.002) within the combined hydration condition. Also, when superficial hydration was applied, mean shimmer % (P = 0.016), MPT (sec) (P = 0.003) and dysphonia severity index (P = 0.020) scores increased significantly in a between-group, post-test comparison. A significant reduction in mean intensity max (dB) (P = 0.049) and intensity min (dB) (P = 0.018) was also observed. Conclusions: This study demonstrates that the use of superficial hydration results in positive outcomes of perceptual parameters of voice quality and symptoms of vocal fatigue in future female professional singers. However, mixed results were observed regarding the acoustic parameters of voice. The superficial hydration data is compelling enough to warrant implementing in a vocal hygiene protocol for singers.