What To Expect During a Sleep Study
Sleep studies are painless. Parents can go with
their children to a sleep study.
The polysomnogram (PSG), multiple sleep latency test
(MSLT), and maintenance of wakefulness test (MWT) are usually 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 any questions that you may have
about the sleep study.
During a Polysomnogram
Sticky patches called sensors are placed on your
scalp, face, chest, limbs, and a finger. While you sleep, these devices 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 each
exhaled breath.
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 to minimize discomfort. You will be able to roll in any direction.
A technician in another room monitors the recordings
as you sleep. He or she fixes any problems with the recordings that occur.
The technician also helps keep you comfortable and
disconnects the equipment if you need to go to the bathroom.
When it's time for you to sleep, the room will be
dark and quiet.
If you show 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 continuous positive airway
pressure (CPAP) mask over your nose and mouth.
The mask is connected to a small machine that gently
blows air through the mask. This creates mild pressure that keeps your airways
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 helps you out
of bed and 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.
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.
Starting 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 three or four 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 four distinct stages.
REM sleep and the four stages of non-REM sleep occur in patterns throughout the
night.
The types and stages of sleep can help your doctor
diagnose a sleep disorder such as
narcolepsy,
idiopathic hypersomnia, or a circadian rhythm disorder.
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 ahead. Then, you simply try to stay awake for a period of
time.
An MWT typically includes four trials lasting about
40 minutes each. If you fall asleep, the technician will wake you after about
90 seconds. There are usually 2-hour breaks between trials. During
these breaks, you can read, watch television, etc.
If you're being tested as a requirement for a
transportation- or safety-related job, you may need a drug-screening test
before the MWT.
During an Actigraph Test
You don't have to go to a sleep center for this
study. The actigraph is a small device that's usually worn like a wristwatch.
You can go about your normal daily routine while you wear it. You remove it
while swimming or bathing.
The actigraph measures your sleepwake behavior
over 3 to 7 days. Results give your doctor a better idea about your sleep
habits, such as when you sleep or nap and whether the lights are on while you
sleep.
You may be asked to keep a sleep diary while you
wear the actigraph. |