This is to confirm that your MSLT (Multiple Sleep Latency Test) is booked at The Wesley Hospital.
After your overnight study, you will stay on to have your MSLT during the day and see the Sleep Physician on the
afternoon of your study. Please read the below information about your upcoming study and be sure to contact us
with any further enquiries you may have.
This test is used to objectively assess the level of daytime sleepiness you have. The test is conducted throughout the day and consists of 4 or 5 distinct periods. After you wake in the morning following your sleep study, you are kept awake for about 2 hours which is then followed by a 20-30 minute nap period. During the nap period, you are asked to lie in bed with the lights off and attempt to fall asleep.
This process is repeated 4 or maybe 5 times a day and the time it takes you to fall asleep is measured each time. If you fall into a deep sleep or if you dream during the nap period, this is also taken into account.
MSLTs are performed to diagnose excessive daytime sleepiness (or daytime Hypersomnolence), or Narcolepsy. They are also performed to distinguish daytime fatigue from daytime sleepiness, which are different conditions.
Most likely you would have had a sleep study before, and this has shown that you don’t have any obvious reason to be sleepy during the day. This test is then used to ‘measure’ how much sleep you get during the day. It is a very useful tool to help diagnose Narcolepsy or Idiopathic Hypersomnolence, which means ‘excessive sleepiness for no other reason’.
This is a condition that makes people feel sleepy just about all the time. While sleeping can relieve the feeling of excessive sleepiness, this soon wears off shortly after being woken. People with Narcolepsy often have sleep attacks as well. These are short episodes where a feeling of overwhelming sleepiness possesses the person. Often they will sit or lie down during these attacks.
Sometimes people will complain of having excessive sleepiness alongside other sleep related abnormalities, including sleep onset hallucinations and sleep paralysis (when your mind wakes up before your body does). Both of these types of events can be very scary for the sufferer but they are not known to cause any health problems.
Narcolepsy can also be accompanied by a condition that causes an overwhelming feeling of dizziness or muscle weakness that is typically associated with periods of heightened emotion (like excitement or anger). This is called Cataplexy and people who experience both of these things may have Narcolepsy-Cataplexy Syndrome.
A light breakfast will be provided upon waking from overnight sleep study. Lunch will be provided to you by us, between 12.00pm and 1.00pm, however if you wish you can bring your own lunch with you.
Should you wish to bring any additional snacks please ensure that any foods or drinks you bring do not contain caffeine or guarana, other limitations are:
• You cannot eat within 30 minutes of starting a nap period
• Snacks must be kept to small portion sizes
As a stimulant or sedative will affect your degree of sleepiness, your Sleep Physician may have given you instructions at your last consultation about whether you are to continue to take these medications at your normal dose or whether you are to gradually discontinue certain medications prior to your MWT. If you are unsure about your medication instructions for the test please contact the Sleep Centre at least two weeks ahead of your test date.
If you were instructed to discontinue a medication, you will need to start reducing your medication dose two weeks prior to the test, and then stop taking the medication completely, one week prior to the test as it takes approximately two weeks for some drugs to be eliminated from your body. This gradual reduction in dosage is necessary to avoid any withdrawal side-effects.
Note: Speak to your Sleep Physician before adjusting or withdrawing ANY medications
You will need to complete a 2 week Sleep Diary prior to the MSLT. In this you will need to detail each night, what time you went to bed, what time you rose from bed, what time you woke up each morning, and what time you were kept awake at night, if at all.
If you need to complete a Sleep Diary, the Sleep Physician will have discussed this with you already.
Reduce by half your normal dosage any medications which you were instructed to discontinue (it’s important not to discontinue these medications abruptly).
Continue to take any other medications at your normal dose.
Discontinue completely any medications which you were instructed to discontinue.
Continue to take any other medications at your normal dose.
If you’re having an MSLT performed you will be required to come in the night before for an overnight sleep study. This is performed exactly the same way as a usual overnight sleep study. Following this though, you will need to stay in the Sleep Lab for the entirety of the MSLT. This test usually lasts about 9-11 hours so you may want to bring something to keep yourself occupied in the breaks.
Please note however that each nap period is timed precisely and you must make yourself ready for the nap period upon request from the Sleep Technician. During the nap period you cannot be distracted by mobile phones, TVs, laptops or games, and thus all of these devices will need to be paused and shut down 30 minutes prior to and during the nap period.
As caffeine and nicotine are stimulants we will ask that you don’t have any caffeine the previous night or on the day of your study. This includes coffee, tea, cocoa, chocolate, cola, and any guarana-containing drinks such as Red Bull, Mother, V, etc. Nicotine cannot be taken, or vigorous exercise performed within 30 minutes of a nap period.
You will need to bring any medications you take during the day.
Also bring anything you wish to occupy yourself with during the day. You are welcome to bring a book, portable game console or laptop/tablet if you wish, however please note there will be no access to Wi-Fi internet.