Plain-language definitions grounded in the clinical and regulatory literature.
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Process
What it isA comprehensive overnight sleep study that simultaneously records brain waves (EEG), eye movements, heart rhythm (ECG), muscle activity (EMG), breathing effort, blood oxygen levels, and limb movements — the most complete physiological picture of sleep available.
Why it mattersPSG is the gold standard for diagnosing sleep disorders like apnea and narcolepsy. It also captures rich whole-body health signals about future disease risk — signals that AI models like SleepFM can now analyze at scale.
Think of it like thisThink of PSG as an overnight flight recorder for your body. Like a black box that captures every system’s behavior during a flight, PSG records every major physiological system during the most revealing eight hours of your day.
Polysomnography is a multi-channel overnight physiological recording combining electroencephalography (EEG), electrooculography (EOG), electromyography (EMG), electrocardiography (ECG), respiratory airflow, thoracoabdominal effort, pulse oximetry, and body position monitoring. Scored by AASM criteria into sleep stages (N1, N2, N3, REM) and respiratory events.
Scientific ConsensusPSG is the accepted gold standard for diagnosing obstructive sleep apnea, central sleep apnea, narcolepsy, REM sleep behavior disorder, and periodic limb movement disorder. Sleep staging rules standardized by AASM.
Active DebateWhether home sleep testing can replace PSG for most diagnoses. Clinical implementation of AI-derived disease risk predictions from PSG data. Cost-effectiveness of expanded PSG-based screening.
Emerging ResearchFoundation AI models trained on large PSG datasets (e.g., SleepFM, 2026) have demonstrated that PSG signals can predict 130+ future diseases including dementia, Parkinson’s, and cardiovascular disease. Home PSG and wearables are expanding access but cannot replicate full lab PSG signal richness.
Key ResearchBerry et al. (2012) updated AASM sleep staging rules, establishing the current global standard. Ohayon et al. (2004) provided normative PSG parameters across 3,577 healthy subjects. Kapur et al. (2017) specified when in-laboratory PSG is preferred over home sleep testing.
— AASM PSG scoring manual v2.0 — current clinical standard for sleep staging and respiratory event scoring
— Normative PSG parameters across the lifespan — age-stratified reference values for clinical interpretation
— AASM clinical practice guideline for OSA diagnostic testing — when in-lab PSG is preferred over home sleep testing
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