Participants will be classified as oral breathers if more than 50% of their total breaths during DISE occur through the oral route; otherwise, they will be classified as nasal breathers. The pattern of upper airway collapse will be characterized using the VOTE classification system, a standardized DISE scoring tool assessing the Velum (V), Oropharynx (O), Tongue Base (T), and Epiglottis (E). Each anatomical site is graded on a 0-2 scale, where 0 = no obstruction, 1 = partial obstruction, and 2 = complete obstruction. This outcome assesses relationships between breathing route classification and the anatomical pattern and severity of upper airway collapse

For each participant, every breath within the analysis window will be classified as oral, nasal, or mixed-approximately 5 minutes of stable breathing during DISE and ≥4 hours during overnight polysomnography (PSG). The primary output will be the percentage of breaths in each category for both modalities. Agreement between DISE-based and PSG-based breathing-route classification will be evaluated using statistical agreement methods (e.g., Bland-Altman analyses, concordance metrics).