The test evaluates how fast you fall asleep in a quiet environment during the day.
It also assesses the sleep stages that you experience during daytime naps.
A multiple sleep latency test differs from othersleep studiesbecause it is given during the day rather than at night.
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This test focuses on naps and explains why people may fall asleep when they should be awake.
Other sleep study tests evaluate overnight sleep patterns.
What Conditions Can It Diagnose?
Narcolepsy
Narcolepsyis a chronic neurological disorder characterized by excessive daytime sleepiness.
It comes up whenever your brain is unable to control normal sleep-wake cycles.
Symptoms can include:
Idiopathic Hypersomnia
This disorder causeshypersomnia(excessive sleepiness) during the day.
Unlike narcolepsy, idiopathic hypersomnia does not involve cataplexy or sudden sleep attacks.
The nighttime polysomnogram is necessary to rule out factors that could impact daytime sleepiness.
During a multiple sleep latency test, you are given 20 minutes to fall asleep for a nap.
You will then continue with the test.
The next nap trial will be set for two hours later.
During this time, you will have to stay awake during the two-hour break.
Factors such as your insurance coverage determine the portion of the fee that you pay.
Data from all naps are combined to create a mean (average) score.
Your healthcare provider will discuss the results of your multiple latency sleep test.
Normal sleep latency is between 10 and 20 minutes.
Abnormal sleep latency is diagnosed according to the following criteria:
How Accurate Is an MSLT?
The multiple sleep latency test is considered the gold standard for diagnosing daytime sleepiness.
It has been shown to be reliable and valid.
An MSLT is part of the diagnostic criteria for narcolepsy and idiopathic hypersomnia.
The MSLT is most accurate when you follow your healthcare provider’s preparation instructions.
Treatments for narcolepsy and idiopathic hypersomnia include behavior modifications and medications.
You may also need treatment for underlying conditions that may add to daytime sleepiness.
A multiple sleep latency test can be the first step in resolving daytime sleepiness problems.
While the test is time-consuming, getting a diagnosis can help you find ways to improve your symptoms.
Ask your healthcare provider for details about this test and why you may need it.
If an MSLT is advised, it may help you return to a normal daily lifestyle.
American Academy of Sleep Medicine.Multiple sleep latency test.
Arand DL, Bonnet MH.The multiple sleep latency test.Handb Clin Neurol.
2019;160:393-403. doi:10.1016/B978-0-444-64032-1.00026-6
National Institute of Neurological Disorders and Stroke.Narcolepsy.
American Thoracic Society.Multiple sleep latency test.
