Sleep Studies

What Is A Sleep Study?

A sleep study is a non-invasive, overnight exam that allows doctors to monitor you while you sleep to see what’s happening in your brain and body.

Sleep studies help doctors diagnose sleep disorders such as sleep apnea, periodic limb movement disorder, narcolepsy, restless legs syndrome, insomnia, and nighttime behaviors like sleepwalking and REM sleep behavior disorder. Often these disorders cannot be identified with a normal office visit so your doctor needs to gather more conclusive evidence while you’re asleep.

The data from your sleep study will be scored by a technologist, and later evaluated by your doctor.

Types of Sleep Studies

There are three basic types of in-lab sleep studies doctors prescribe to diagnose sleep related problems:

Polysomnogram (PSG)

A polysomnogram is an overnight test that records several body functions during sleep including brain activity, heart rate, blood pressure, oxygen levels, eye movement, breathing and body muscle movements. This test can help diagnose the following:

  • Sleep related breathing disorders such as obstructive sleep apnea
  • Sleep related seizure disorders
  • Sleep related movement disorders such as periodic leg movements disorder (PLMD)
  • Sleep related disorders caused by excessive daytime sleepiness

Multiple Sleep Latency Test (MSLT)

A MSLT is a daytime study that measures how sleepy you get during the day.  It usually follows a PSG study and records whether you fall asleep during the test, and if so which stages of sleep you enter. This test is key to diagnosing Narcolepsy that causes of daytime tiredness.

Maintenance of Wakefulness Test (MWT)

This study measures whether you can stay awake during a time when you normally should be alert and awake. This test is often prescribed to diagnose shift worker disorder or jobs that involve public transportation.

CPAP Titration

Following your sleep study, the doctor may prescribe a second test called a CPAP titration. The CPAP titration study is essentially the same as the polysomnogram with the addition of the CPAP therapy.

A titration is performed to determine the optimal CPAP pressure setting required to resolve apnea episodes.  During the titration, the patient wears a mask and CPAP pressures are dialed up and down during sleep to find a single best pressure delivery and setting to control apnea events.