Objective: To analyze whether the moment of performing nebulization influences acoustic measurements in women post-dehydration.
Method: Forty dehydrated (four hours without liquids, caffeine, and alcoholic beverages) women (mean age 30.3 years) were randomly divided into four groups. The Vocal Signs and Symptoms list was applied (average 1.58) before intervention and the voice was recorded before and after the intervention (sustained vowel [a] and connected speech – CAPE-V sentences). The interventions for each group were: CG: phonation into a flexible tube (FT) (35cmX0.9cm) immersed in water for 3 minutes (ascending and descending tones); G1: hydration with nebulization for 10 minutes with 5 ml of isotonic saline solution followed by the phonation into FT (identical to the CG); G2: hydration with nebulization (same conditions as G1) associated with the FT identical to the CG; G3: only nebulization (same conditions as G1). A group of 23 acoustic measurements were extracted using the Prosody Descriptor Extractor script.
Results: Eight measures showed significant differences in their values regarding the type of task and intervention. Mean f0 increased in the vowel and in connected speech in G1 and CG. Spectral emphasis increased only in the sustained vowel in G1, G2 and CG. Also, in the sustained vowel, there was a decrease in shimmer (G1), jitter (G1 and CG) and Soft Phonation Index (G2 and G3). Shimmer and Harmonic-to-noise ratio increased in G2 (vowel and connected speech). The coefficient of variation of intensity showed higher values in G2 and G3 compared to G1 and CG. The long-term measure (LTAS slope 0-1000 Hz and 1000-4000 Hz) varied its behavior according to the group: increase (G1) and decrease (G3) in the sustained vowel. G1 and GC presented more changes, with the most significant changes in G1 (nebulization followed by FT), suggesting greater vocal range, better vocal quality, less noise and glottal cycle disturbance; these data indicate that hydration before exercise enhances the results obtained.
Conclusion: Nebulization followed by FT (G1) had a greater impact on the acoustic measurements. In a dehydration context, performing nebulization simultaneously with vocal exercise may not be as effective as performing them sequentially.