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What to Expect in a Sleep Study

Preparing for Your Polysomnogram

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Updated November 06, 2013

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

What to Expect in a Sleep Study
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So your doctor recommends you undergo a sleep study, but what should you expect? Though you may have some anxiety about the experience, take a few moments, read on and lay those fears to rest.

What Is the Purpose?

Sleep studies, or polysomnograms, are tests to diagnosis sleep disorders. They generally involve spending the night sleeping at a sleep laboratory or sleep center. Typically, these studies will be ordered after you have seen a healthcare provider at a clinic visit and have discussed your sleep problems. These tests are the best means in understanding how you sleep.

Before Your Visit

Prior to arriving for your sleep study, there are some important preparations that should be made. Most sleep laboratories will have patients arrive in the early evening hours, but check with your center before your appointment. If you work nights, some facilities are able to accommodate studies during the day. It will be important to avoid caffeine, alcohol and naps the day of your study, as these may interfere with your ability to sleep.

Restrictions on What to Bring

It will be important to check with your sleep center to see if they have special restrictions for you. In general, patients are encouraged to bring comfortable sleepwear, their own pillows or favorite blankets and other "comfort items" that may help you sleep (such as your childhood teddy bear). Unfortunately, pets and bed partners will not be accommodated. If there is something you can’t sleep without, it may not hurt to ask ahead of time.

What to Expect at the Sleep Center

There are hundreds of sleep centers across the country, and each one will vary some in its accommodations. ome are based in hospital wards, others in free-standing buildings and, still others, in empty hotel rooms. There will be a bed, bathroom facilities and the equipment necessary to complete the study. There may be bedroom furniture, a television and a range of other amenities. Some rooms are sparse and others are extravagant. If you are curious about what the rooms look like, ask to arrange a visit during the daytime.

Getting Set Up for the Study

After arriving and making yourself comfortable, the sleep technician - or sleep tech – will ask you to change into your sleepwear. Everyone will be more comfortable if you wear something to bed, but if you don’t wear pajamas, a loose-fitting T-shirt and shorts will do nicely. The technician will then spend about 45 minutes setting you up for your sleep study. This time can vary, depending on their efficiency and the complexity of your individual set-up. Some studies for seizures may take as long as two hours to set up.

The technician will measure the dimensions of your head and mark landmarks on your scalp with a marking pencil. The marks are not permanent and will wash off with soap and water. At designated places, a small cotton-tipped applicator, such as a Q-tip, will be used to clean a small patch of your skin. The cleaning paste is a little abrasive, but it is important to clean off the oils of your skin.

Then wires with gold-cupped electrodes will be put in to place for the EEG. Paste will be applied to each electrode. It serves to keep the wires in place as well as to better conduct the electrical waves of your brain. This paste is sticky, similar to shortening used in cooking, but will also wash off. Some of the wires on the face will be taped in place. There are no needles in modern sleep electrodes, and this preparation should not hurt.

In addition to the electrodes on your face and scalp, there are a few other items that shall be applied. The exact set-up may vary from one sleep center to another, but these are standard to most:

  • a flat, plastic snore microphone taped to your neck
  • sticky pads on your chest to monitor your heart rhythm
  • stretchy cloth belts that go across the chest and stomach to measure breathing
  • sticky pads applied to your shins or forearms to monitor movements (an EMG)

All of these wires will be connected to a small box. This box can be carried around, so don’t worry that you won’t be able to get up after being wired.

Finally, just before going to bed, a nasal cannula - which is plastic tubing that sits in the nose - will be applied. It will not give you oxygen, but will rather measure airflow. Some laboratories may use a thermistor, which is a pronged wire that sits in the nostrils and measures temperature differences.

What to do Before You Sleep

After getting set up, some patients worry about what they will be doing before they sleep. Most technicians will have one or two other patients to set up, so you will have some time when you are left alone. It is important to not fall asleep before starting the study, and most people bring reading materials or other things to work on. It may be possible to bring your computer, a DVD player or even something to listen to. Many people find the evening very relaxing - there are no dishes to be done and no one else around to bother you!

Some centers will have their patients watch an educational video about sleep disorders. If you are likely to need continuous positive airway pressure (CPAP) during the night, you may be fitted with a mask and practice with this before going to bed.

When the Night Begins

When you have reached your bedtime, or you feel drowsy enough to fall asleep, it will be important to let your technician know. They will help you in to bed and connect the wire box to a computer that will allow the tech to monitor you from another room. There will likely be a small infrared camera and two-way speaker in the bedroom. If you need to get up during the night, this is how you will call for assistance.

Just prior to going to sleep, the technician will need to test the equipment. As part of this testing, you will open and close your eyes, move them around, snore, take breaths in and out and even move your arms and legs. If something goes wrong with a wire, or if one comes loose during the night, your technician will come in to fix it.

Will I Sleep?

The biggest concern most people have is whether they will be able to sleep. Surprisingly, most individuals are able to sleep, even with all the wires, the strange environment and any number of things that could be disruptive. It is exceptionally rare to have someone not be able to sleep at all.

If you are concerned that you may not be able to fall asleep, some healthcare providers prescribe a sleeping medication to be used the night of the study. There are some that will not change the results of your sleep study. Make certain that all medications are approved by your doctor before using them the night of the study.

The Morning After

Most people get up at a regular time, and if you let your sleep technician know this before going to bed, they will be happy to wake you (there may be no clocks in the bedroom). The wires and other measurement devices will be removed with surprising speed, perhaps in as little as 5 minutes. There may be a questionnaire about your night's sleep to complete.

Some centers have showers, and you may be able to get ready for your day before leaving. (Remember that the sleep technicians have been awake all night, and they are eager to get home to sleep too.) You will likely not be given any information about your study until a sleep doctor has had a chance to review the results, which could be a few weeks.

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