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How to Prepare for an Overnight Sleep Study

How to Prepare for an Overnight Sleep Study

An overnight sleep study, also called a polysomnogram, is a procedure which monitors body functions such as brain waves, heart rate, leg movements and breathing during sleep. You will be monitored by a sleep technologist all night long. There are different types of sleep studies.  Diagnostic studies are used to evaluate whether you have a sleep disorder.  Therapeutic studies are performed to determine the ideal pressure settings for PAP therapy.

A technologist will greet you at approximately 8:00pm or 9:30pm in the emergency room admitting area and will show you to your bedroom. It is important that you arrive on time! 

Once you are settled in your bedroom, you will change into your own bedclothes and complete some paperwork.  Then the sleep technologist will painlessly apply electrodes and sensors which take about an hour.  Sensor attachment will be done utilizing a prep (a glue-like substance) and medical tape.  Please prepare for this process by thoroughly washing your hair before your visit to our lab.  After the sensors are in place, you will be able to walk around the bedroom and use the restroom unassisted.

You may go to sleep at your normal bedtime within the constraints of the lab protocols.  Keep in mind, the earlier you go to bed, the more time we have to evaluate your sleep.  Some patients may be started on PAP during the night (a “split-night study”).

Throughout the night, a technologist will be available to assist you as needed.

Typically, we begin waking patients at 6 am, unless a later or earlier wake up time is desirable. Please keep in mind that the equipment takes approximately 20 minutes to remove.  There is a shower available to wash up after all of the sensors have been removed.

When to Arrive:

Please arrive at 8:00 pm or 9:30pm, as instructed.

Cancellation Policy

If you need to cancel your overnight sleep appointment please make every effort to do so AS SOON AS POSSIBLE, but not later than 3 pm,  by calling  815-564-4687.  If you call after office hours, please leave a message detailing cancelation or late arrival.

What to Bring to Your Overnight Sleep Study

There are a number of key items that you should bring with you to your sleep study, including:

  • Appropriate bedclothes (preferably two-piece pajamas).  Nightgowns and one-piece pajamas sets are not acceptable attire, and nudity is not permitted.
  • If you use a CPAP/Bilevel machine bring your current mask.  If you do not know your current pressure or have been instructed by your sleep physician, bring your CPAP/Bilevel.
  • Please take your evening medications prior to your appointment; the hospital does not allow patients to use their home meds for safety reasons. Prescription and non-prescription medications are not dispensed at the Sleep Center with the exception of a sleeping pill, which may be provided if you have trouble falling asleep, per doctor’s order.
  • Personal toiletries (toothpaste, toothbrush, comb, brush, shampoo, etc.), and a change of clothes for the next day. The lab provides towels and bedding (but no toiletries) and there is a bathroom with shower in each room. 
  • Please feel free to bring a special pillow, stuffed animal, or white noise device if desired. Children should bring favorite blankets, books, or toys.
  • No animals unless medically authorized.

Where to Go:

The CGH Sleep Center is located at CGH MEDICAL CENTER, 100 E. LeFevre Road, Sterling IL 61081. The Sleep Center is on the first floor.

Our telephone number is (815)564-4687. If you have difficulty staying alert while driving please make arrangements for transportation to and from the lab.

Who Can Stay with Me?

For adults, limited family members/friends (1-2) are welcome to accompany you until your bedtime.  Guests are not permitted to stay overnight.

For children under 18 years of age, disabled, or otherwise non-independent patients, we require and allow only one parent/caregiver to stay overnight.  A recliner is available in the room for the caregiver to sleep.  Sharing the bed will interfere with the sleep study and it is not allowed.

What about Food?

Please eat before you arrive.  You may bring snacks and drinks for refreshments.  The cafeteria is closed overnight, but there are vending machines available on the ground floor.

Meal service is only provided for patients scheduled for daytime nap testing (MSLT or MWT).  Please be sure to eat dinner prior to arrival.

How Much Will This Cost?

If you have an HMO plan, you must have your referral and authorization approved by your primary care physicians in advance of your scheduled appointment.

It is your responsibility to know your insurance coverage and benefits. Call the customer service number on your insurance card and ask for eligibility for benefits.  You will need the CPT codes below when inquiring about coverage.

Visit Type


CPT Codes

Overnight Sleep Study (PSG)

a.  Technical/Facility charge



b.  Professional charge 


CPAP/Bilevel/Split Treatment

a.  Technical/Facility charge



b.  Professional charge



a.  Technical/Facility charge



b.  Professional charge



What Happens Next?


You will receive a phone call to discuss the results.  Please allow at least 7 business days before expecting a phone call. If the study was not ordered by one of our sleep specialists, please call your referring physician.

Other Frequently Asked Questions:

Why record all of these things?

These parameters are recorded to obtain objective information about the quality of sleep to better define your sleep problem.

How can I sleep with all of these things on me?

The body sensors are applied in a manner that will allow you to turn and move during your sleep. Generally, you will not be aware that you are wearing the devices after they have been on for a short time. The lab technical team makes the environment as comfortable as possible, within the constraints of a monitored setting.

Will the sensor devices cause discomfort?

Sometimes, in preparing the sites for sensor application, there are mild temporary irritations; please inform us if you have any known sensitivity to particular tapes or if you have a latex allergy.

Do all rooms have a double bed and private restrooms?

At the CGH Sleep Center, we see all types of patients so our bedrooms and restrooms all are handicap accessible and have queen size beds to accommodate all patient populations including bariatric patients and individuals with disabilities.  All of the bedrooms have private restrooms with a shower.  

Can I use my own CPAP/BiPAP machine?

During a sleep study, information about your CPAP/BiPAP pressure is recorded as part of your sleep study, therefore lab machines are used. Your sleep specialist may instruct you to bring your mask and equipment to your appointment to check the pressure setting.

Can I smoke?

No smoking is allowed on the premises or anywhere in CGH Medical Center.


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