Narcolepsy test

MULTIPLE SLEEP LATENCY TEST (MSLT)

A test to measure excessive fatigue by checking your ability or tendency to fall asleep at several times during the day

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What is narcolepsy

Narcolepsy is a sleep disorder that causes excessive daytime sleepiness. You may fall asleep at inappropriate times, including while talking, working or even driving.

The multiple sleep latency test (MSLT) can be done as part of a sleep study in hospital and can confirm a diagnosis of narcolepsy.

Need to know

What happens during the sleep study?

The MSLT will be started in the morning following an overnight sleep study in hospital. Your consultant will have attached several sensors to your head, tummy and chest the day before. These sensors measure a range of bodily functions while you sleep, including brain waves, eye movement, pulse and breathing rate. The test involves four or five nap opportunities at two hour intervals throughout the day. At each nap opportunity you'll be given 20 minutes to try to fall asleep. If you fall asleep, you'll be woken up after 15 minutes. You'll be asked to try and stay awake between each nap.

How to prepare

Your consultant will explain the test to you and answer any questions you may have. They'll let you know if there is anything specific you'll need to do to prepare. This may include avoiding certain medications or caffeine before the test. If you're a smoker, you may also need to avoid or limit smoking.

After your sleep study

After the test, your consultant will let you know about any next steps. If you're not having any further sleep studies, you should be able to return home the same day. You may need to come back for a follow-up appointment to review the results of the test with your consultant and discuss options for treatment or further assessments if needed.