How Are Sleep Disorders Diagnosed?

Depending on what your symptoms are, your doctor will gather various kinds of information and consider several possible tests when trying to decide if you have a sleep disorder:

• Sleep history and sleep log. Your doctor will ask you how many hours you sleep each night, how often you waken during the night and for how long, how long it takes you to fall asleep, how well rested you feel upon awakening, and how sleepy you feel during the day. Your doctor may ask you to keep a sleep diary for a few weeks. Your doctor may also ask you if you have any symptoms of sleep apnea or restless legs syndrome, such as loud snoring, snorting or gasping, morning headaches, tingling or unpleasant sensations in the limbs that are relieved by moving them, and jerking of the limbs during sleep. Your sleeping partner may be asked if you have some of these symptoms, as you may not be aware of them yourself.
• Sleep recording in a sleep lab (polysomnogram). A sleep recording refers to a polysomnogram (poly-SOM-no-gram) or PSG test that is usually done in a sleep center or sleep laboratory. You will likely stay overnight in the sleep center with electrodes and other monitors placed on your scalp, face, chest, limbs, and finger. While you sleep, these devices measure your brain activity, eye movements, muscle activity, heart rate and rhythm, blood pressure, and how much air moves in and out of your lungs. This test also checks the amount of oxygen in your blood. A PSG test is painless. In certain circumstances, the PSG can be done at home. A home monitor can be used to record heart rate, how air moves in and out of your lungs, the amount of oxygen in your blood, and your breathing effort.
• Multiple Sleep Latency Test (MSLT). Particularly useful for diagnosing narcolepsy, this test measures how sleepy you are during the day. In this test, typically done after an overnight sleep recording (PSG), monitoring devices for sleep stage are placed on your scalp and face. You are asked to nap four or five times for 20 minutes every 2 hours during times in which you would normally be awake. Technicians note how quickly you fall asleep and how long it takes you to reach various stages of sleep, especially REM sleep, during your naps. Normal individuals either do not fall asleep during these short designated nap times or take a long time to fall asleep. People who fall asleep in less than 5 minutes are likely to require treatment for a sleep disorder, as are those who quickly develop REM sleep during their naps.

It is important to have a sleep medicine specialist interpret the results of your sleep monitoring test (PSG) or MSLT.