This infographic helps you understand the key metrics reported in a sleep study, how to interpret them, and what they mean for your sleep health. It highlights the main indices, typical ranges, and how different study types affect the data you receive.
Key Takeaways
- AHI (Apnea-Hypopnea Index): Average number of complete (apnea) or partial (hypopnea) breathing pauses per hour of sleep. Primary metric for Obstructive Sleep Apnea (OSA) severity.
- RDI (Respiratory Disturbance Index): AHI plus Respiratory Effort-Related Arousals (RERAs); typically higher than AHI and captures subtle disruptions that disturb sleep.
- ODI (Oxygen Desaturation Index): Number of times per hour the blood oxygen drops by 3% or 4% from baseline.
- Sleep Efficiency: Percentage of time spent sleeping out of total time in bed; target is >85% for good sleep quality.
- Sleep Latency: Time taken to fall asleep. Normal is <30 minutes; <5 minutes may indicate narcolepsy or severe sleep debt.
- Arousal Index: Total awakenings or 'micro-arousals' per hour. Normal is <20 per hour (age-dependent).
- Study Types: Level 1 (In-Lab PSG), Level 2 (Full Home PSG), Level 3 (HSAT); different setups affect data completeness and interpretation.