Sleep Medicine Services

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The Multiple Sleep Latency Test (MSLT) is a daytime sleep study that measures how sleepy you are. It's typically done the day after a polysomnogram (PSG). The MSLT is primarily used to diagnose excessive daytime sleepiness and narcolepsy.

What to expect

With most of the same sensors attached to you that were present during your polysomnogram, you will be given five nap trials. These nap opportunities will help us determine how sleepy you are.

  • You'll start between 1.5 to three hours after your normal wake-up time.
  • Sensors are placed on your head, face, and chin, which will show when you are asleep or awake during the test.
  • A low-light video camera allows a technologist to see you from a nearby room.

Between trials, you will have to stay out of bed and occupy yourself so that you remain awake. The majority of normal sleepers stay wake for an average of eight minutes or more or stay awake during the entire trial. An abnormal result occurs if you fall asleep in less than eight minutes.

Your test will be examined by a Riverside sleep specialist and the physician who referred you to the Center for testing will review test results with you.