If you are one of the more than 12 million Americans who suffer from a sleep disorder that interrupts your breathing and your ability to sleep well, your doctor may recommend that you undergo a sleep study.
The most common sleep study is an “all night” sleep test called a Polysomnogram. This test will record your brain and muscle activity, eye movements, breathing and oxygen saturation. Additionally, most sleep studies will include a Multiple Sleep Latency Test to measure how long it takes for you to fall asleep as well as a Maintenance Wakefulness Test to measure whether or not you can stay awake during the normal hours you are awake.
Once all the information is gathered, it is scored using the following criteria.
- Sleep Onset Latency: The normal time to fall asleep after “lights out” is less than 20 minutes. A sleep study will measure the time you take to fall asleep based upon your Electroencephalography (EEG), which measures brain wave activity.
- Sleep Efficiency: This is number of minutes of sleep divided by the number of minutes in bed. A normal score is above 85%.
- Sleep stages: Stages 1 and 2 represent light sleep, stage 3 is deep sleep. These are all non-REM (Rapid Eye Movement) sleep stages. Stage 4 is REM sleep which occurs about 20-25% of sleep time.
- Breathing irregularities: Breathing irregularities are mostly caused by apneas, a condition caused by the muscles of the throat relaxing enough to restrict airflow and cause snoring which can cause an abrupt arousal.
- Other: Cardiac rhythm abnormalities, leg movements, body position and oxygen saturation are also scored against the norm.
Getting a good night’s sleep is very important to your health. Conversely, sleep disorders negatively impact your health and can indicate the presence of serious conditions like heart failure, depression, obesity and hypertension. The good news is, the cost for sleep study is usually covered by insurance, so do not hesitate to have yourself evaluated if you suspect you have a sleep disorder.