Polysomnogram (PSG) with MSLT

What's A PSG with MSLT?

The PSG is a sleep study that helps determine whether or not you have a sleep disorder such as sleep apnea, narcolepsy, or unusual behaviors during sleep. The study records your sleep patterns, such as brain waves, heart rate and breathing, eye and leg movements, and the oxygen level in your blood. A PSG can be done at night or during the day.

The multiple sleep latency test (MSLT) determines excessive daytime sleepiness by measuring how quickly you fall asleep in a quiet situations during the day, and how quickly and how often you enter REM sleep. The MSLT is sometimes referred to as the daytime nap study and is used to diagnose narcolepsy or idiopathic hypersomnia.  It’s always a follow-up test to the overnight PSG.

When you arrive for your sleep study, a Registered Polysomnographic Technologist or Respiratory Therapist will be at the site to greet you and show you to your room. After you make yourself comfortable, your technologist will take a brief history, explain the study process, and answer any questions you may have prior to applying the sensors. This process is completely painless and generally takes about 40 minutes to make sure everything is placed correctly. 

What to Expect?

Preparing for Your Sleep Test

Sleep Insights offers a relaxing environment with private, hotel-like rooms and at certain locations, a shower may be available.

Set Time Aside

The PSG with MSLT is an overnight test followed by a daytime test. After you spend the night, the PSG will end at approximately 6:30am and the MSLT will start at 8am. 

Plan on being at our sleep center from approximately 7:00-9:00 pm until 5:00pm the following day.

NOTE: Six or more hours of sleep are needed during the Polysomnogram (PSG) in order to proceed with the daytime MSLT. If you’re unable to sleep the required amount, in the morning we won’t be able to proceed with the MSLT and will ask to you reschedule the PSG with MSLT.


Please avoid napping the day of your test.

Avoid Caffeine

Please avoid caffeine intake after dinner on the day of your study. We have caffeine free beverages available at the sleep center for you.

Wash and Dry Your Hair

Wash and dry your hair thoroughly but do not use conditioners or other hair products.

Hair Accessories

Remove any hair weaves or extensions. We cannot do testing if you have either of these.

Acrylic or Applied Nails

If you have acrylic, dip or applied (“fake”) nails an index fingernail needs to be removed for the oxygen reading. If you have gel nail polish, the polish from one of the index fingers will need to be removed. Regular nail polish is fine. The oximeter does not read through acrylic or applied nails, nor gel polish.

What Should I Wear?

Wear comfortable, loose-fitting, two-piece clothing. You must wear pajamas or two-piece clothing for the test.


Bring – and take – all of your normally scheduled medications unless otherwise directed by your doctor or the staff at Sleep Insights.

Special Requirements and Guests

Guests are not allowed to stay overnight with patients other than for specific medical reasons (e.g. parent with a child, caregiver for patient with special needs). Arrangements for caretakers must be made with advanced notice and with prior permission from their provider. Anyone accompanying a patient to their sleep test who isn’t an approved caretaker must leave at 9pm.


Smoking, vaping and the use of alcohol are not permitted in the building or on the premises at any time.


Cancellations must be made by at least 12 noon the day before your study, or if your study is on a Saturday or Sunday, by noon on the Friday before.

Failure to show up for your scheduled sleep study will result in a $100.00 no-show charge.