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Multiple Sleep Latency Test (MSLT)

​The Multiple Sleep Latency Test (MSLT) is a test to study:

  1. How quickly you fall asleep in the day when in a quiet environment
  2. Level of daytime sleepiness
  3. How often and how quickly you enter the rapid-eye-movement (REM) stage of sleep. The REM stage of sleep stimulates areas of the brain that are essential in learning and retaining memories

The MSLT monitors the following activities while you nap:

  • Brain waves
  • Heart beat
  • Eye movements
  • Chin muscle activity
  • Breathing
  • How quickly and how often you enter the REM stage of sleep.

The results of this test are used to detect sleep disorders such as narcolepsy, a condition which causes daytime drowsiness and sudden napping.


How should I prepare for the test?

Before the day of test

  • Have at least seven to nine hours of good sleep.
  • Avoid smoking and drinking beverages with caffeine e.g. coffee, tea at least eight hours before the test.
  • Stop taking sleep-promoting medications or supplements one to two days before. Speak to your doctors if you are unsure.
  • Wash your hair.

On the day of test

  • Do not use hair styling products e.g. foam, cream, gel, oil.
  • If you would like to wash your hair, ensure that it is fully dry before coming for your appointment.
  • Have a proper meal before your appointment.

How is the test performed?

The test is done by a medical technologist.
The test begins at 8.00am and takes eight to nine hours. You will be asked to take four to five naps at the Neurodiagnostic Laboratory (NDL) with one and a half to two hour breaks in between each nap.

  • This test is done while you are lying down.
  • Your scalp is measured and marked for electrodes to be placed.
  • Your scalp is cleaned using a gel.
  • Electrodes are attached to your scalp, face, chin and abdomen using a safe and washable paste or tape.
  • The electrodes are connected to a machine to record activity where the electrodes have been placed and how long it takes for you to fall asleep.
  • At the start of each nap session, you will be asked to do the following to ensure that the electrodes are in the correct position:
    • Blink / open / close / move your eyes
    • Clench your teeth
  • The lights will be turned off and you will be asked to take a nap.
  • If you fall asleep within 20 minutes, you will be woken up after 15 minutes. This ends one nap session.
  • If you do not fall asleep within 20 minutes, your nap session ends.
  • There will be a break of one and a half to two hours before the next nap session starts.
  • During your breaks, you may walk around the vicinity or eat/drink.
  • You are not allowed to take naps, smoke, drink caffeinated beverages e.g. coffee, tea as this will affect the test results.
  • This process is repeated four to five times.
  • When the test is done, the electrodes are removed, the paste is washed off and you can go home.
  • A detailed report will be sent to your doctor within two weeks. Your doctor will discuss the findings with you at your next appointment.


Frequently Asked Quetions

Is the test safe?

The test is generally safe. The electrodes do not produce any electrical discharges and do not cause pain. The medical technologist will be with you throughout the process. If you feel unwell, tell the technologist.

Can I undergo the test if I am feeling unwell?

No. If you are feeling unwell e.g. fever, cough, do not proceed with the test. Call to reschedule your appointment.


Have questions or concerns? Call:

Tel: 6330 6363

Office Hours:
8.00am – 5.30pm, Mon – Wed, Fri
8.00am – 5.00pm, Thurs
Closed on Sat, Sun, Public Holidays

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The information is correct as of July 2021 and subject to revisions without notice.