The Use of Nebulization for Voice Across Different Vocal Demands: A Scoping Review

To map the available evidence on nebulization and other hydration strategies for voice across different vocal demands, focusing on intervention characteristics, outcomes, and reported effects.

Scoping review.

This scoping review was conducted following the Joanna Briggs Institute (JBI) methodology and reported according to PRISMA-ScR guidelines. The protocol was registered on the Open Science Framework (DOI: 10.17605/OSF.IO/T8XVE). Searches were performed in PubMed, Scopus, and the Cochrane Library without restrictions on year or language. Studies involving adults and investigating nebulization or hydration strategies for voice were included. Data extraction covered study characteristics, intervention protocols, and vocal outcomes. Results were synthesized using descriptive analysis and mapping of outcomes.

Ten studies were included. Most studies were quasi-experimental and involved healthy participants. The most frequent interventions were surface hydration (40%), followed by nebulization with saline solution (20%), systemic hydration (20%), and combined strategies (20%). Acoustic outcomes were the most frequently used (90%), followed by auditory perceptual measures (60%) and aerodynamic measures (40%). Nebulization with saline solution demonstrated the most consistent positive results, particularly in acoustic and perceptual outcomes. Surface hydration strategies also showed predominantly positive effects, while systemic hydration presented less consistent findings. Aerodynamic outcomes were more variable across studies. Overall, the results were heterogeneous and influenced by differences in intervention protocols, solution types, and device characteristics.

The available evidence suggests that saline nebulization and surface hydration may be associated with improvements in selected vocal outcomes, particularly acoustic and perceptual measures. However, these findings should be interpreted cautiously because of the small samples, methodological limitations, and substantial heterogeneity across studies. Current evidence is insufficient to establish an optimal nebulization protocol or determine its efficacy across different vocal populations. Future controlled studies should prioritize standardized intervention protocols, detailed characterization of aerosol delivery, and multidimensional outcome assessment.