Pathology · single question
What is the gold standard diagnostic test for obstructive sleep apnea (OSA)?
Show answer and explanation
Correct answer: C. Overnight polysomnography (PSG/sleep study)
Overnight polysomnography (PSG) is the gold standard for diagnosing OSA. It simultaneously measures: EEG (brain activity/sleep stages), respiratory airflow, oxygen saturation, chest/abdominal movement, and heart rate. The AHI (apnea-hypopnea index) derived from PSG classifies OSA severity.
- A. ❌ Epworth Sleepiness Scale screens for daytime sleepiness but does not diagnose OSA.
- B. ❌ Pulse oximetry shows O2 desaturations but is not the comprehensive gold standard.
- C. ✅ Overnight polysomnography — the gold standard; measures all parameters needed for OSA diagnosis and severity.
- D. ❌ Cephalometric radiograph can identify anatomical risk factors but does not diagnose OSA.