Imaging
Polysomnography
PSG · Sleep study · In-lab sleep study
The gold-standard sleep study — full electroencephalography, breathing, oxygen, leg movement, and video over one night in a sleep lab.
What it measures
Sleep stages (via EEG/EOG/EMG), respiratory events, oxygen saturation, leg movements, body position, and cardiac rhythm. Yields a full AHI with proper sleep staging, plus ability to detect central apneas, periodic limb movements, parasomnias, and REM-related abnormalities that HSAT misses.
Reference context
1 guideline source
PSG-derived AHI is the reference; treatment decisions are typically based on PSG values when both PSG and HSAT have been performed.
Population context — consult guideline targets below
Mechanism
Why moving this marker matters
PSG is the reference standard against which all other sleep-diagnostic technology is validated. Appropriate for complicated cases, ambiguous HSAT, suspected central apnea, suspected parasomnias, and pediatric sleep disorders.
Guideline targets
What major guidelines recommend
AASM (AHI thresholds, adults)
<5 normal; 5–14 mild; 15–29 moderate; ≥30 severe OSA
How to measure
The test, where to get it, when to repeat
Method
Arrive at a sleep lab in the evening; multiple sensors attached (~30 minutes); sleep overnight while monitored; depart in the morning. Some labs offer split-night studies with CPAP titration in the same session.
Where
Hospital-affiliated or specialist sleep labs. Typically requires referral.
Typical cost
€400–1,200 private; covered by most public systems on appropriate referral.
Fasting
Not required
When to test
AASM 2017
Indicated when HSAT is inconclusive, when comorbidities or atypical presentations exist, for suspected central apnea, periodic limb movement disorder, parasomnias, or pediatric assessment.
Where to scan
Providers offering this imaging study
These providers offer the scan directly to consumers. You book and pay with them; the imaging report lives on their platform. Healicus is not in the clinical chain.
Healicus is not the provider. Your contract for the service is with whoever you choose. Links labelled Sponsored are paid affiliate relationships; unlabelled links are editorial reference only. See our disclosure for the full policy.
Context
Reading the numbers
PSG-derived AHI is the reference; treatment decisions are typically based on PSG values when both PSG and HSAT have been performed.
Caveats
Single-night first-night effect (slightly worse sleep than normal in the lab) is real but doesn't usually shift the diagnostic category.
Practices
What's been shown to influence this marker
Sleep apnea screening
Program·Untreated obstructive sleep apnea drives cardiovascular and metabolic risk. Screen if you snore loudly, are tired despite enough hours, or have hypertension.
Why
Obstructive sleep apnea (OSA) is common (~10-15% of adults), often undiagnosed, and causally linked to hypertension, cardiovascular events, cognitive decline, and all-cause mortality. STOP-BANG is the most validated screening questionnaire. Diagnosis is by polysomnography or home sleep apnea testing. CPAP and other treatments substantially reduce risk in moderate-severe OSA.
The program
- 1
Take the STOP-BANG questionnaire (free online).
- 2
If 3+ positives, ask your GP for a sleep study referral.
- 3
Home sleep apnea testing or in-lab polysomnography confirms the diagnosis.
- 4
If moderate-severe, options include CPAP, mandibular advancement device, weight loss, positional therapy.
- 5
Re-screen if sleep quality degrades again after weight or lifestyle change.
Practical
Cadence
One-time screening; re-test if symptoms return
What you'll need
STOP-BANG questionnaire (online, 8 yes/no questions)
Ideal for
Loud snorers, witnessed apneas, daytime fatigue despite adequate sleep duration, hypertension, large neck circumference, BMI ≥35.
Markers this may influence
Evidence
See also
Related markers
Take to your physician
Worth discussing
- Whether you need PSG vs HSAT.
- If split-night CPAP titration is appropriate.
- Treatment plan based on PSG findings.
Sources
Cited literature
Edited by Carl Pöhl, MD · Healicus editorial
Last reviewed May 2026
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