Multiple Sleep Latency Test

This daytime sleep study measures how sleepy you are. It typically is done the day after a PSG. You relax in a dark, quiet room for about 30 minutes while a technician checks your brain activity.

The MSLT records whether you fall asleep during the test and what types and stages of sleep you're having. Sleep has two basic types: rapid eye movement (REM) and non-REM. Non-REM sleep has three distinct stages. REM sleep and the three stages of non-REM sleep occur in regular cycles throughout the night.

The types and stages of sleep you have can help your doctor diagnose sleep disorders such as narcolepsy, idiopathic hypersomnia , and other sleep disorders that cause daytime tiredness.

An MSLT takes place over the course of a full day. This is because your ability to fall asleep changes throughout the day.

Maintenance of Wakefulness Test

This daytime sleep study measures your ability to stay awake and alert. It's usually done the day after a PSG and takes most of the day. Results can show whether your inability to stay awake is a public or personal safety concern. Results also can show how you're responding to treatment.

Actigraphy

Actigraphy is a test that's done while you do your normal daily routine. This test is useful for all age groups and doesn't require an overnight stay at a sleep center. An actigraph is a simple device that's usually worn like a wristwatch. Your doctor may ask you to wear the device for several days and nights, except when bathing or swimming. Actigraphy gives your doctor a better idea about your sleep schedule, such as when you sleep or nap and whether the lights are on while you sleep. Doctors can use actigraphy to help diagnose many sleep disorders, including circadian rhythm disorders (such as jet lag and shift work disorder). Doctors also may use the test to check how well sleep treatments are working. Actigraphy might be used with a PSG or alone.