Split Night Study

What's A Split Night Study?

The Split Night Study is a painless test that determines what type and degree of sleep apnea you have, as well as the level and type of PAP (positive airway pressure) therapy most appropriate for you. This test is typically done at night.

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. 

Next, your technologist will ask you questions about how you believe you breathe during the night in order to assess what type of mask will work best for you. In case you meet the criteria to have a CPAP mask during the night, you’ll be fitted with one at this time and given time to relax quietly with the mask on so you can get comfortable with it.

What to Expect?

Your technologist will begin applying the sensors, using stickers to affix leads on your legs and chest. You will also have two belts placed around your chest and abdomen that monitor your body’s efforts to breathe.

Next, your head will be marked and measured with a paper ruler and a grease pencil. This is done because each electrode on your head needs to be in a precise location. Once this is complete, a skin prep jelly will be applied to clean the scalp for the electrodes. 

Electrodes are then placed on the surface of your scalp with a small amount of paste.  The prep, paste, and tape are hypoallergenic.

You’ll also have a nasal cannula (similar to an oxygen cannula) to monitor your breathing. You will not receive oxygen during your PSG.

This process is completely painless and generally takes about 40 minutes to make sure everything is placed correctly.

Once you’re fitted with the sensors, you can relax in your room, catch up on phone calls, enjoy Smart/Cable/Vios TV, Wi-Fi, or read until “Lights Out” at 11pm. Yes, you may eat, drink, and use the bathroom throughout the night! We want you to feel comfortable and relax as you would at home prior to going to sleep. You may bring your own food/snacks. Should you need to get up at all during the night, simply let your technologist know. 

During the first portion of the test, your technologist will be monitoring the type and severity of apnea you may have.  If you’ve had enough sleep and your apnea meets the severity threshold, your technologist will come in to apply your mask. They will awaken you gently, remove the monitoring cannula from your nose, and place your mask on you. If you don’t have a mask applied that doesn’t mean you don’t have apnea–it just means there wasn’t enough sleep time or a severe enough degree of apnea that would allow CPAP therapy to be started.

Your technologist will monitor your sleep throughout the study and will be available to answer questions and ensure you’re comfortable. 

When the study is done in the morning, the technologist will waken you and remove the wires and sensors. Any remaining paste or marks can be easily washed out using warm water and shampoo. 

If you were fitted with a mask during the night, you will typically be contacted within 7-10 days by the durable medical equipment (DME) vendor you have selected to schedule picking up your PAP therapy device. 

If you weren’t fitted with a mask during the night you’ll be scheduled for a follow up appointment with your provider to review the results of your study.

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

This is an overnight test. Plan to be at our sleep center overnight until approximately 6 a.m. the next morning.

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 nails 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.

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.


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.