Sleep Disorders: Diagnosis

If a sleep disorder is suspected, your health care provider may refer you to a sleep clinic for an evaluation by sleep specialists. A sleep specialist will use a variety of information to evaluate your sleep problem. It may include: a detailed history, medication history, physical exam, sleep diary, sleep study and other testing.

• Detailed History: A sleep specialist will ask you questions about your health and symptoms. Your sleep partner may be asked questions about what he or she observes. Questions about your sleep habits and sleep schedule will be asked.

• Medication History: Your medication will be reviewed to see if these may be playing a role in your symptoms.

• Physical Exam: During a complete physical exam, the doctor may look for a deviated nasal septum, nasal congestion, enlarged tonsils or a narrowed airway, which may give clues to snoring or sleep apnea.

• Sleep Diary: Over a one- to two-week period, you will record information about how well and how often you sleep. Your doctor may discuss the sleep diary data with you and determine the next steps to take.

• Sleep Study: A sleep study may be ordered to make a diagnosis. No needles are involved, and it is relatively simple and painless. There are two types of sleep studies, an in-laboratory study and a home sleep study:

  • An in-laboratory "sleep study,” also called a polysomnogram, is a noninvasive test that records your physical state during various stages of sleep. It provides essential data to evaluate sleep and sleep-related complaints and problems, such as identifying sleep stages, body position, blood oxygen levels, respiratory events, muscle tone, heart rate, eye movement, brain waves, amount of snoring and general sleep behavior.

  • If you are being tested for sleep apnea, you may undergo a "split-night" test, in which half the night will be used to diagnose your sleep problem, and the other half will be used to determine the best way to treat the problem. Or you may be asked to return for another sleep study to help determine the best treatment for you.

  • A home sleep study may be requested to evaluate for sleep apnea. This study is performed in your own home without the presence of a sleep technologist. There are fewer sensors used than with an in-laboratory study. Consequently, less information is obtained, resulting in a less accurate test than in-laboratory testing; however, this test is usually sufficient to evaluate for sleep apnea.

• Other Testing: Other tests may be ordered to determine your sleep schedule, your level of sleepiness or your ability to stay awake. Tests may be performed to look for stimulants, opiates and anti-anxiety medicines that may be contributing to your symptoms.

Types of Other Tests

Other types of tests used to help diagnose a sleep condition include:

• Lab Tests: Your doctor may order lab tests. These may include drug screening for stimulants, opiates and anti-anxiety medicines. These medicines are known to affect the level of alertness. Blood tests, such as iron studies or thyroid studies, can sometimes be helpful.

• Multiple Sleep Latency Test (MSLT): This test objectively determines your degree of sleepiness. On the day following an overnight sleep study, you will be asked to take four or five naps over an 8 – 10 hour period. Each nap period lasts about 20 minutes. During these nap periods, you will be closely monitored, as you were during your sleep study.

• Maintenance of Wakefulness Test (MWT): This test measures your ability to stay awake. It consists of four nap opportunities, each lasting 40 minutes. During the nap period, you will be asked to try to stay awake. Most people without excessive sleepiness remain awake during these nap periods.

• Actigraphy: For this test, a device called an actigraph is worn on the wrist like a watch. Signals are recorded when movement is detected. There are few to no signals recorded during sleep or inactivity. This can provide information about periods of rest/sleep activity. The device may be worn for several days or weeks if needed.