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Types of Sleep Studies

Diagnostic Polysomnography (PSG)

Polysomnography is used to diagnose, or rule out, many types of sleep disorders including Narcolepsy, Restless Legs Syndrome, REM Behavior Disorder, Parasomnias, and Sleep Apnea. PSG is often ordered for patients with complaints of daytime fatigue or sleepiness that may be caused by interrupted sleep. The test consists of a continuous recording from 6 to 8 hours and occurring during a patient's typical sleep hours. The parameters are monitored using a Philips Respironics Healthdyne model Alice 5 computerized polygraph. A polysomnogram typically records a minimum of eleven channels requiring a minimum of 22 wire attachments to the patient. Two channels are for the EEG, one or two measure airflow, one is for chin movements, one or more for leg movements, two for eye movements (EOG), one for heart rate and rhythm, one for oxygen saturation and one each for the belts which measure chest wall movement and upper abdominal wall movement.

The Sleep Study recording is interpreted by a Board Certified Sleep Specialist who will determine the diagnosis and provide a treatment recommendation.

Continuous Positive Airway Pressure (CPAP) Titration

If a patient is diagnosed with Obstructive Sleep Apnea during a diagnostic polysomnogram then a CPAP titration may need to be performed. CPAP is initiated and the pressure is increased by the technician until your breathing or body oxygen is normalized and Obstructive Apnea has been eliminated, especially while supine and during REM sleep when sleep apnea tends to be at its most severe.

PSG with CPAP Titration (Split Night Polysomnogram)

PSG with CPAP trial is a combination test which incorporates diagnostic study and CPAP titration in one night. Split Night Polysomnogram is conducted when mild, moderate or severe Sleep Apnea has been discovered or strongly suspected during the first part of the study. If there is time, the second half of the night is then used for CPAP Titration.

Multiple Sleep Latency Test (MSLT)

The MSLT is usually performed during the day following after your sleep study. The Multiple Sleep Latency Test (MSLT) is a sleep disorder diagnostic tool. It can be used to test for Narcolepsy. It is used to measure the time it takes from the start of a daytime nap period to the first stage of sleep, called sleep latency. The test consists of 4 to 5 nap opportunities occurring every 2 hours lasting approximately 20-35 minutes following the PSG.

Maintenance of Wakefulness Test (MWT)

The Maintenance of Wakefulness Test (MWT) is usually performed during the day followed after an overnight sleep study. The (MWT) is used to measure how alert you are during the day. It shows whether or not you are able to stay awake for a defined period of time. This is an indicator of how well you are able to function and remain alert in quiet times of inactivity. A series of four tests are taken at 2 hours intervals. Each test requires the patient to sit in a chair for 40 minutes and try to remain awake.

Preparing for Sleep Study

The following preparation should be made just before your overnight stay:

• Shower or shampoo your hair.
• Avoid using anything on your hair after it has been cleaned and dried.
• Do not wear makeup or jewelry.
• Do not use creams or lotion on your face or body.
• Do not wear acrylic nails or hair braids/weaves that can affect sensor placement.
• Pack your sleepwear and toiletries.
• Bring your reading glasses, if applicable, for use in completing paperwork.
• If you prefer, bring your own pillow, blanket and any reading material or other items that can help you pass the time before bedtime.

During Your Sleep Study

When your study begins, the technologist will ask you to be seated and the process of placing special sensors on various points of your body will begin.

Depending on the type of sleep study prescribed, the sensors may be placed in the following locations:

On your scalp

On your forehead

On your templates

Near your eyes

Under your nose

On your chin

On your finger

On your chest

On your leg

The technologist will explain the purpose of each sensor as it is being placed. Sensors are placed using a type of medical paste and you should not experience any pain or discomfort with this process.

After the placement of the sleep monitoring gear, you are free to relax until bedtime. Please inform the technologist of your normal sleep and waking times. When possible, we will try to accomodate your sleep study.

At Bedtime

Just before bedtime, the technologist will attach the long leads (wires) from your sensors to the computer monitoring system that is located at your bedside.

While it might seem a bit awkward to sleep with the many wires running from your sensors to your bedside monitoring equipment, it should not create any discomfort or impair your normal ability to sleep or to get up during the night, should you need to use the restroom.

The technologist will be nearby and will be continually monitoring your sleep study on our sleep diagnostic system.

When Getting Up

Following your sleep study, the monitoring gear is removed. In those areas of the body hair, there may be slight pulling sensation when the sensor is being removed, much like the removal of a band-aid.

You may use the restroom, freshen up and get dressed for discharge. The results of your sleep study will be forwarded to your sleep physician for interpretation and the recommendation of a treatment that's right for you.

Daytime Study (MSLT)

If patient presents with symptoms of narcolepsy or to measure the level of sleepiness if complaints of excessive daytime sleepiness. Following is the procedure to perform Multiple Sleep Latency Test (MSLT).

Procedure

A MSLT would be performed when a patient presents with symptoms of narcolepsy or to measure the level of sleepiness if complaints of excessive daytime sleepiness.

1. The naps begin with 1 1/2 - 3 hours after the overnight sleep study.
2. The patient should be in street clothes during MSLT.
3. The patient is not allowed to consume caffeine or alcohol during the study and if they smoke, they must have had their last cigarette 30 minutes prior to the beginning of any nap.
4. Each nap will start two hours after the previous nap.
5. If the patient does not fall asleep then the nap will end after 20 minutes from lights off.
6. If the patient does fall asleep then the nap will end 15 minutes from sleep onset.
7. A fifth nap will be given only if the patient demonstrates one REM period during the first four naps.

Getting Your Sleep Study Results

The physician, who ordered your sleep study, should have the results ready within a few days. Also, the results and recommended treatment may be shared with your primary care physician. Depending on your diagnosis, either the doctor ordering your study or your sleep physician will be handling your treatment.

With certain sleep disorders, such as sleep apnea, it may be necessary for you to return to the sleep laboratory for a second therapy related study.

Home Sleep Testing

Another option currently used is Home Sleep Testing which is only indicated in patients who have a high probability for having severe Obstructive Sleep Apnea and for whom formal in-lab Polysomnography cannot be accomplished. These are referred to as a Level 3 Sleep Study. Patients are sent home with a portable monitoring device that connects around the abdomen with strap. There is a connection worn on the index finger which measures oxygen saturation and a nasal cannula with measures airflow. Usually a deposit is required which is then refunded upon return of the equipment the following day. This is a diagnositic study and so is not recommended for CPAP titration studies.