Sensitivity Analysis and Uncertainty Quantification of Nanoparticle Deposition from Tongue Morphological Variations

Area of Science:

• Aerosol science
• Biomedical engineering
• Computational fluid dynamics

Background:

• Human tongue morphology is highly variable.
• The role of tongue shape in regulating respiratory flows and inhaled aerosol deposition is not well understood.

Purpose of the Study:

• To quantify uncertainty in nanoparticle deposition due to tongue shape and position variability.
• To rank the importance of different tongue morphological factors on aerosol deposition.

Main Methods:

• Reconstructed oropharyngeal models with varied tongue postures.
• Used a k-ω model for multiregime flows and Lagrangian tracking for aerosol simulation.
• Trained a Gaussian process regression surrogate model for sensitivity analysis.

Main Results:

• Particle size is the primary determinant of nanoparticle deposition.
• Central tongue shape variations have a greater impact on total deposition than back tongue or glottal aperture.
• Back tongue influences throat deposition, while central tongue affects oral deposition.
• Flow rate interactions with morphology significantly impact throat deposition.
• Smaller nanoparticles (2-nm) show higher deposition uncertainty than larger ones (100-nm).

Conclusions:

• Tongue morphology, particularly central tongue shape, plays a crucial role in inhaled nanoparticle deposition.
• Understanding these variations is essential for predicting aerosol behavior in the upper airway.
• Interactions between airflow and tongue shape are critical, especially in the pharyngolaryngeal region.