Sleep
Study
Definition
A test of sleep cycles and stages
through the use of continuous recordings
of brain waves (EEG), electrical
activity of muscles, eye movement (electrooculogram),
respiratory rate, blood pressure, blood
oxygen saturation, and heart rhythm and
direct observation of the person during
sleep.
There are 2 states of sleep:
non-rapid eye movement (NREM) sleep and
rapid eye movement (REM) sleep. REM
sleep is associated with dreaming and
generalized muscle paralysis sparing the
eye muscles and diaphragm. NREM sleep
has 4 stages distinguishable by EEG
waves. REM sleep alternates with NREM
sleep approximately every 90 minutes. A
person with normal sleep usually has 4
to 5 cycles of REM and NREM sleep during
a night.
Why is
the Test Performed?
The test is performed for insomnia,
excessive daytime sleepiness,
obstructive sleep apnea, breathing
difficulties during sleep, or behavior
disturbances during sleep.
How is
the Test Performed?
Polysomnograms may be conducted in a
sleep study center. You will lie on a
bed in the test center. The test may be
carried out during the night so that
normal sleep patterns can be reproduced.
Electrodes are placed on the scalp, the
outer edge of the eyelids, and to the
skin on the chin in preparation for the
test. Characteristic patterns from the
electrodes are recorded during
wakefulness with the eyes closed and
during sleep. The time taken to fall
asleep is measured as well as the time
to enter REM sleep. Sometimes the
movements of a person during sleep are
recorded by video camera
How to
Prepare for the Test?
Do not take any sleeping medication
and do not drink alcohol or
caffeine-containing beverages before the
test.
How will the
Test Feel?
Electrodes will be placed on the skin
and scalp. Monitors to record heart rate
and respiratory rate (breathing) will be
attached to the chest. Sometimes other
test to determine breathing disorders
during sleep are also performed |
