Sleep studies are painless. The polysomnogram (PSG), multiple sleep latency test (MSLT), and maintenance of wakefulness test (MWT) usually are done at a sleep center.
The room the sleep study is done in may look like a hotel room. A technician makes the room comfortable for you and sets the temperature to your liking.
Most of your contact at the sleep center will be with nurses or technicians. You can ask them questions about the sleep study. They can answer questions about the test itself, but they usually can't give you the test results.
During a Polysomnogram
Sticky patches and sensors called electrodes are placed on your scalp, face, chest, limbs, and a finger. While you sleep, these sensors record your brain activity, eye movements, heart rate and rhythm, blood pressure, and the amount of oxygen in your blood.
Elastic belts are placed around your chest and abdomen. They measure chest movements and the strength and duration of inhaled and exhaled breaths.
Wires attached to the sensors transmit the data to a computer in the next room. The wires are very thin and flexible and are bundled together so they don't restrict movement, disrupt your sleep, or cause other discomfort.
If you have signs of sleep apnea, you may have a split-night sleep study. During the first half of the night, the technician records your sleep patterns. At the start of the second half of the night, he or she wakes you to fit a CPAP (continuous positive airway pressure) mask over your nose and/or mouth.
The mask is connected to a small machine that gently blows air through the mask. This creates mild pressure that keeps your airway open while you sleep.
The technician checks how you sleep with the CPAP machine. He or she adjusts the flow of air through the mask to find the setting that's right for you.
At the end of the PSG, the technician removes the sensors. If you're having a daytime sleep study, such as an MSLT, some of the sensors may be left on for that test.
Parents usually are required to spend the night with their child during the child's PSG.
During a Multiple Sleep Latency Test
The MSLT is a daytime sleep study that's usually done after a PSG. Sensors on your scalp, face, and chin usually are used for this test. These sensors record brain activity. They show various stages of sleep and how long it takes you to fall asleep. Sometimes your breathing also is checked during an MSLT.
A technician in another room watches these recordings as you sleep. He or she fixes any problems with the recordings that occur.
About 1.5 to 3 hours after you wake from the PSG, you're asked to relax in a quiet room for about 30 minutes. The test is repeated four or five times throughout the day. This is because your ability to fall asleep changes throughout the day.
You get 2-hour breaks between tests. You need to stay awake during the breaks.
The MSLT records whether you fall asleep during the test and what types and stages of sleep you have. Sleep has two basic types: rapid eye movement (REM) and non-REM. Non-REM sleep has three distinct stages. REM sleep and the three stages of non-REM sleep occur in patterns throughout the night.
The types and stages of sleep you have during the day can help your doctor diagnose sleep disorders such as narcolepsy and idiopathic hypersomnia.
During a Maintenance of Wakefulness Test
This sleep study occurs during the day. It's usually done after a PSG and takes most of the day. Sensors on your scalp, face, and chin are used to measure when you're awake or asleep.
You sit quietly on a bed in a comfortable position and look straight...