How is obstructive sleep apnea (OSA) definitively diagnosed?

Obstructive sleep apnea is definitively diagnosed by polysomnography (PSG) — a comprehensive overnight sleep study conducted in a sleep laboratory that monitors: brain waves (EEG), eye movements (EOG), muscle activity (EMG), heart rhythm (ECG), airflow, respiratory effort, oxygen saturation (SpO2), and body position. The apnea-hypopnea index (AHI) quantifies severity: AHI 5–14 = mild, 15–29 = moderate, ≥30 = severe OSA. Home sleep apnea testing (HSAT) is an alternative for uncomplicated cases. Dentists play a role in screening (Epworth scale, Mallampati score) and treating mild-moderate OSA with mandibular advancement devices (MADs).