Neurophysiology - Multiple Sleep Latency Test

Introduction

An MSLT is a test that measures how quickly and how deeply you fall asleep in a relatively quiet environment. It is a standard test to help diagnose certain sleep disorders. Prior to the MSLT you will be asked to complete the enclosed diary for the week before your actual appointment. This information is used to assess your usual sleep habits. Without this information we may not be able to fully report the test.

An MSLT takes all day and consists of 4 or 5 test sessions spread evenly throughout the day each lasting in total approximately 35-50 minutes. In between sessions you may leave the department if you wish but return at your next allotted time.

Please bring something to occupy yourself and any food, snacks or drinks you’d like (caffeine free, no energy drinks). Please do not smoke 30 minutes prior to each test.

You will arrive at the Neurophysiology department at approximately 8.30am on the morning of your test. The first test will be conducted at 9am. The subsequent naps will occur in 2 hour intervals.

Why do an MSLT?

An MSLT when combined with a history, examination and other test results may help to diagnose a wide range of sleep disorders. (Note - you may have a polysomnography test in another department the night before your MSLT or you may have been asked to attend for an overnight at home ambulatory study which is set up in the Neurophysiology department).

Your referring consultant will be able to explain why it is important for you to have this test.

How is an MSLT recording performed?

Each of the 4 or 5 MSLT recordings are identical. Approximately 16 small electrodes are placed on your head using a sticky paste and possibly some special glue/bandages. Sticky pads will be placed around your eyes, chin and arms.

The electrodes monitor your brain wave activity, your eye movement, muscle activity and heart rate respectively and this allows us to record how fast and how deeply you fall asleep.

You will lie down in your most comfortable position, the lights will be dimmed or switched off and you will have the opportunity to go to sleep. There is no pressure to go to sleep.

After 20-35 minutes or so the first recording will end and if you are asleep you will be woken up.

After each recording you may leave the department. You will have use of the recording room for the whole day.

It is a good idea to bring something to occupy you. During these times, please refrain from napping, sleeping, taking caffeinated products such as coffee, tea, fizzy drinks, energy drinks or chocolate.

You may eat and drink normally otherwise. There are cafes and shops in the Hope Building if you’d like to buy your own lunch or browse. Please return to the department for your next recording at the time specified by your Healthcare Scientist.

At least 4 recordings will be carried out throughout the day, after the fourth recording, the Healthcare Scientist will let you know if you if we have obtained sufficient information or you may need to stay for a fifth recording.

At the end of the day, the electrodes/bandages are removed and most of the paste/glue is cleaned from your head.

Any residue will wash out when you get home with water and shampoo. If glue is used, you will be advised on how to remove any residue. It is a good idea to bring a comb or brush with you to the appointment to tidy your hair after the test.

What are the side effects and risks?

There are no side effects or increased risks to having the MSLT itself. It is painless. In exceptional cases, people with sensitive skin may experience redness at one or more of the electrode sites.

What happens if I decide to have an MSLT?

You will have the opportunity to ask the doctor or Healthcare Scientist questions about the information in this booklet before you decide whether or not to have an MSLT. There will be no formal consent form.

As soon as you agree to the test we can begin. The entire procedure usually takes all day. The recordings usually take place around 9:00am, 11:00am, 1:00pm and 3:00pm. If a fifth recording is required, this will take place around 5:00pm.

Please do not wear any hair gel, make up foundation, oils or applications on the day of the test. Recent (within the week) hair colours or perms may interfere with the test.

What happens if I decide not to have an MSLT?

You may decide to decline the MSLT. Your referring consultant will need to discuss the likely consequences of this decision. For example, he/she may find it more difficult to diagnose and/or treat your condition.

Is there anything else I should know?

• Please arrive in good time for your appointment
• If you think you will be late, please telephone us as soon as possible
• It may be necessary to re-book another appointment for you
• Parking can be difficult - please allow for this, it can take up to 40 minutes to park depending upon how busy the hospital is. Please park on the East Car Park on Stott Lane which is closest (5-10 minutes’ walk) to our department. There is a charge for parking, please bring enough money/change with you. Parking information and site map are available online at: www.northerncarealliance.nhs.uk
• The test cannot read your thoughts or emotions
• This test is safe in pregnancy
• Please do not drink or eat caffeinated products on the day of your test (e.g. coffee, tea, fizzy drinks, chocolate or energy drinks, Red Bull etc). You may eat and drink normally otherwise
• For health and safety reasons, please do not bring children of any age to your appointments
• If you are currently taking any medication you should continue to do so, unless otherwise advised by your own GP or consultant
• If you require an ambulance, you should contact your own GP to make the arrangements. Please let us know if you will be coming by ambulance
• You may be invited back to have further tests if the consultant in our department or your referring doctor/consultant thinks that a repeat test or a different test may be helpful
• In this case you may receive an appointment for another test before seeing your referring doctor/consultant for the results of your first test. The main reason for this is to save time and inconvenience for you

Contact details

Telephone:0161 206 2068
Email: reftoneurophys@nca.nhs.uk
Department of Clinical Neurophysiology,1st Floor, Barnes Building Salford Royal Hospital, Stott Lane, Salford, M6 8HD.