What is the gold standard diagnostic test for obstructive sleep apnea (OSA)?

Overnight polysomnography (PSG) - also called a sleep study - is the gold standard diagnostic test for obstructive sleep apnea. PSG simultaneously monitors brain waves (EEG), eye movements (EOG), muscle activity (EMG), heart rate (ECG), airflow, respiratory effort, blood oxygen saturation, and leg movements. It provides the Apnea-Hypopnea Index (AHI): mild OSA (5-14/hour), moderate (15-29/hour), and severe (30+/hour). Dental relevance: dentists can fabricate mandibular advancement devices (MADs) as an alternative to CPAP for mild-moderate OSA, but diagnosis must be confirmed by a physician using PSG.