Polysomnography

Definition

Polysomnography is a sleep study. This test records certain body functions as you as you sleep, or try to sleep. Polysomnography is used to diagnose sleep disorders.

Alternative Names

Sleep study; Polysomnogram; Rapid eye movement studies; Split night polysomnography; PSG; OSA - sleep study; Obstructive sleep apnea - sleep study; Sleep apnea - sleep study

How the Test is Performed

There are two states of sleep:

REM sleep alternates with NREM sleep about every 90 minutes. A person with normal sleep most often has four to five cycles of REM and NREM sleep during a night.

A sleep study measures your sleep cycles and stages by recording:

Polysomnography can be done either at a sleep center or in your home.

AT A SLEEP CENTER

Full sleep studies are most often done at a special sleep center.

AT HOME

You may be able to use a sleep study device in your home instead of at a sleep center to help diagnose sleep apnea. You either pick up the device at a sleep center or a trained therapist comes to your home to set it up.

Home testing may be used when:

How to Prepare for the Test

Whether the test is at a sleep study center or at home, you prepare the same way. Unless directed to do so by your doctor, do not take any sleep medicine and do not drink alcohol or caffeinated beverages before the test. They can interfere with your sleep.

Why the Test is Performed

The test helps diagnose possible sleep disorders, including obstructive sleep apnea (OSA). Your health care provider may think you have OSA because you have these symptoms:

Polysomnography can also diagnose other sleep disorders:

Normal Results

A sleep study tracks:

Most people have short periods during sleep where their breathing stops or is partly blocked. The Apnea-Hypopnea Index (AHI) is the number of apnea or hypopnea measured during a sleep study. AHI results are used to diagnose obstructive sleep apnea.

Normal test result show:

What Abnormal Results Mean

In adults, test results above 5 may mean you have sleep apnea:

To make a diagnosis and decide on treatment, the sleep specialist must also look at:

References

Chokdroverty S, Avidan AY. Sleep and its disorders. In: Daroff RB, Jankovic J, Mazziotta JC, Pomeroy SL, eds. Bradley's Neurology in Clinical Practice. 7th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 102. PMID: 22265700 www.ncbi.nlm.nih.gov/pubmed/22265700.

Qaseem A, Holty JE, Owens DK, Dallas P, Starkey M, Shekelle P; for the Clinical Guidelines Committee of the American College of Physicians. Management of obstructive sleep apnea in adults: a clinical practice guideline from the American College of Physicians. Ann Intern Med. Sep. 24, 2013. PMID: 24061345 www.ncbi.nlm.nih.gov/pubmed/24061345.

Vaughn BV. Disorders of sleep. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 405.

Wakefield TL, Lam DJ, Ishman SL. Sleep apnea and sleep disorders. In: Flint PW, Haughey BH, Lund LJ, et al, eds. Cummings Otolaryngology: Head & Neck Surgery. 6th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 18.


Review Date: 1/27/2016
Reviewed By: Allen J. Blaivas, DO, Division of Pulmonary, Critical Care, and Sleep Medicine, VA New Jersey Health Care System, Clinical Assistant Professor, Rutger's New Jersey Medical School, East Orange, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
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