Sleep (cont.)

Doctors use a number of different tests to evaluate sleep and determine whether a sleep disorder is present. A careful medical history and physical examination are performed to help identify any medical conditions that may be interfering with the person's sleep. The health care practitioner will also ask about the use of prescription and non-prescription medications as well as alcohol, tobacco, and caffeine use. Laboratory tests may also be used to help diagnose any medical conditions that may cause sleep problems.

In some cases, specialized testing is recommended to help determine whether or not a person may be suffering from a sleep disorder. Some of the most common sleep tests include the following:

• Polysomnography is often simply referred to as a "sleep study." In this test, doctors use electrodes attached to the face and scalp to measure brain waves (electroencephalogram or EEG) and muscle tone during a night's sleep. Other body functions such as airflow, breathing effort, blood oxygen levels, leg movements, electrocardiogram (ECG), and body position may also be measured if needed. Sleep studies are most commonly performed in specially designed labs in hospitals or clinics.
  
  
• The multiple sleep latency test (MSLT) is designed to measure daytime sleepiness. The test is based upon the fact that the sleepier an individual is, the faster he or she will fall asleep. In this test, the patient is given four to five opportunities to nap in a quiet, dark room, usually at two hour intervals during the day. Body functions such as EEG and muscle tone are measured as in polysomnography. The time period needed from wakefulness to sleep onset is measured to determine the "sleep latency." This is repeated during each of the naps, and an average time for sleep latency across all the naps is calculated. Usually a sleep latency of 5 minutes or less is signifies severe daytime sleepiness.
  
  
• Related to the MSLT is the maintenance of wakefulness test (MWT), which measures the individual's ability to stay awake when reclining in a quiet, darkened room.
  
  
• The Epworth sleepiness scale is a questionnaire that is given to patients, often as part of an office visit to a health care practitioner. The test asks individuals to rate how likely they would be to fall asleep in a number of situations (such as a passenger in a car, sitting quietly after lunch, etc.).

Source: MedicineNet.com
http://www.medicinenet.com/sleep/article.htm