Whenever sleep issues arise without a known cause there is a common diagnostic tool used called a sleep study.  There are many different types of sleep studies that can detect what may be interrupting your sleep cycles and at what stage of sleep these problems are occurring.  The two phases of sleep that create majority of our time spent asleep are rapid eye movement (REM) and non-rapid eye movement (non-REM).  These sleep phases alternate approximately 4 to 6 times a night lasting about 90 minutes to make a full sleep cycle.  Interruptions during this cycle schedule can affect how efficient your body is at staying asleep.

Sleep Studies Available

Testing may be done in a sleep laboratory but can also be completed at home if the equipment required is available and portable.  There are three commonly used sleep studies available for diagnostic testing.  These studies are the Polysomnogram, Maintenance of Wakefulness Test (MWT), and Multiple Sleep Latency Test (MLST).  The Polysomnogram is a sleep study that records many different functions of the body while sleeping such as, chest and stomach movement, muscle movement, brain activity, eye movement, heart rate, heart rhythm, and respiratory functions including the flow of air through the nose and mouth, snoring, breathing rate, breathing rhythm, and oxygen and carbon dioxide blood levels.  To test your ability to stay awake during your normal awake hours you would undergo the MWT sleep study.  The next sleep study (MSLT) measures the time it took to fall asleep and whether you are going through both sleep phases of REM and non-REM sleep.

For sleep problems regarding the body’s circadian rhythm, the internal clock we all have, there is a sleep study called the actigraphy.  This study requires wearing a device on your wrist that measures your movement while asleep and awake.  The results of this test can show the doctor what times are more frequent for activity and the hours spent sleeping that may help diagnose issues like shift work sleep disorder.

Benefits of Sleep Study Testing

Performing a sleep study may help diagnose life-threatening disorders or causes of many different other illnesses.  Sleep apnea is a common disorder that causes an individual to stop breathing in their sleep, which could potentially lead to death.  Snoring, narcolepsy (difficulty staying awake), sleepwalking, bed-wetting, night terrors and insomnia may also be diagnosed with a sleep study.  These sleep problems could be triggered by stress, physical pain, hunger, mental illness, and more.  As mentioned before, shift work sleep disorder is also diagnosed via a sleep study but may occur due to a nighttime shift or a varying work schedule.  Other conditions that may benefit from sleep study testing include periodic limb movement disorder and restless leg syndrome, which both involve involuntary muscle movement of the limbs.

Sleep Study Preparation

To get the most accurate results from your sleep study, it is important to follow the protocol given by the physician.  Some common requirements include tracking activity, changing medication schedules, and dietary restrictions.  Tracking your sleep activity may help show any normal patterns to your physician; this can be done using a sleep diary for one to two weeks before you undergo testing.  Following your normal routine and avoiding naps will help the sleep study go as planned.  Medication schedules, and certain drugs such as sedatives, may influence the sleep study, so informing your physician of your current medication regimen will be helpful.  Just as sedatives may decrease the accuracy of the testing, so can caffeine.  Cutting back on caffeinated food and beverages may be required for preparation of the sleep study.

The day before the sleep study, make sure to take a shower or bath to strip your hair and body of any sprays, gels, oils, and lotions on your hair and skin.  The equipment often uses your fingers and face for placement, making it important not to wear makeup, polish, or fake nails for the testing.  If you are not having the sleep study performed at your house, make sure you pack a bag with the personal items you would need for your nightly routine at home.  Some of these items may be a specific blanket, pillow, book you are reading, and hygiene items.  Also, double check that you have filled out any forms requested by the sleep laboratory including information about sleep patterns.  If you frequently sleep next to another individual, asking him or her may also give a new insight on habits you may not be aware of yourself. Your physician is the best source of information for your specific needs on preparation, how the test is performed, and what the results will mean for you.

Sleep Study Process

The process for the various sleep studies will be determined on the type of testing you will undergo but are similar despite the laboratory you may utilize.  The sleep study will occur during your normal sleep time, which is evening hours for many but can also be during the daytime if that is your typical sleep schedule.  The area may resemble a hotel room with a private area for sleeping and the test will more than likely be conducted by a trained sleep laboratory technician.  You may need to arrive a few hours early to prepare for the testing and to complete any extra paperwork.  If you complete the sleep study at home, the equipment will be used at home while you sleep.

Polysomnogram studies are performed using electrodes places on your head and body with glue and tape.  This process is not painful but may take some time to place the electrodes on the proper corresponding location.  These electrodes will measure the activity while sleeping such as, chest and stomach movement, muscle movement, brain activity, eye movement, heart rate, heart rhythm, and respiratory functions including the flow of air through the nose and mouth, snoring, breathing rate, breathing rhythm, and oxygen and carbon dioxide blood levels.  To measure your breathing, soft belts will be placed around your chest and abdomen to measure your respirations.  Blood oxygen levels will be monitored using either your finger or earlobe with a small clip called an oximeter to identify the percentage of oxygen your body is receiving.  While some of these tools may seem obtrusive to a normal sleep pattern, they are designed to help you stay as relaxed as possible during testing.  Before beginning the sleep study, some controls will be observed to ensure the equipment is performing accurately.  The medical equipment will measure the observations that will be visible on the video recording also taking place.  After the controls are documented, the testing will begin and remain monitored until at least six hours of sleep is met in the laboratory.  If your testing is due to sleep apnea, you may need to use the medical equipment to deliver oxygen as normal, such as a CPAP (continuous positive airway pressure) machine.  This mask forces your airway open by regulating the air pressure in your throat while sleeping.

The Maintenance of Wakefulness Test will utilize the same medical equipment as the Polysomnography sleep study; however, the duration of the testing will last longer to assess how easily you are able to stay awake after you sleep for the night.

For the Multiple Sleep Latency Test you will also be connected to the equipment using electrodes as in the other two tests explained.  For this test, you will sleep normal through the night but the following day you will fall asleep for a nap every two hours.  If you fall asleep within the 20 minutes given to nap, you will be woken up 15 minutes in to the nap.  After this, you will stay awake until the next time to take a nap.  The focus of observation for the napping will be the amount of time it took to fall asleep along with the sleep cycles in those 15 minutes of naptime sleeping.

Sleep Study Home Observation

To complete the sleep study at home your physician will give you portable equipment to use while you are sleeping in your own bed.  This may require sleeping with tubes in your nose along with a cap on your finger.  Recording your noises made during sleep will be done with a device to wear, along with a band that monitors movement of your lower limbs while sleeping.  The portable equipment may not be as accurate but can be helpful if accessing the sleep laboratory is inconvenient for your sleep study.

Sleep Study Risks Involved

The sleep study is not painful but it may feel awkward to sleep while connected to the observation equipment.  The biggest risk to the sleep study is a skin reaction from the glue for the electrodes but that can be removed with a shower after your testing.  There are no other risks related to undergoing a sleep study.

Interpreting Sleep Study Results

The sleep study results are best reviewed with a sleep medicine specialist, family doctor, internist, or your pulmonologist.  The sleep laboratory technician is not permitted to review results, only administer the testing.  Results may take anywhere from one to two weeks after the sleep study is administered.  When reviewing the sleep study results, the following are considered normal parameters for each test.

The Polysomnogram sleep study would be normal if:

• the sleep time, sleep phases, and awake time are all normal, along with no seizure activity
• slow eye movements for non REM sleep and rapid eye movements during REM sleep are present
• no jerking movements of the muscles
• blood oxygen levels stay over 90%
• no slow or fast heart rate or rhythm out of the patient’s norm
• there is no reduced or blocked air flow
• respirations move normal without laborious movement
• night terrors, sleep walking, and sleep talking are not present
• excessive snoring is not present
• there is no obtrusion of airflow

The Maintenance of Wakefulness Test would show to be normal if the patient maintained being awake for about 40 minutes and the Multiple Sleep Latency Test normal result would be to take 10 to 20 minutes to fall asleep.

Other Concerns

Some situations occur that may lead to not being eligible for a sleep study or false results, and can be further determined by speaking with your physician.  These include using caffeine, nicotine, alcohol, sedatives, changes to your typical schedule, equipment coming off during the testing, or the noises of the laboratory affecting your ability to sleep.

It is also important to consider other health conditions that may be leading to sleep problems.  Parkinson’s disease, mental illness, obesity, heart conditions, respiratory diseases, and restless leg syndrome all may have a role in causing sleep issues.  Once you receive your results from your first sleep study, you may undergo a second sleep study if you could benefit from treating an underlying disorder found in initial testing.  If reflux may be a concern, there is a test available to monitor the pH levels of the stomach while sleeping and is performed by placing a wire into the nose down to the esophagus.

Finally, if the sleep study was not successfully performed, a second one may be utilized to obtain results that are more accurate.  There is also an option of splitting the sleep study in half to observe sleep with and without treatment, such as using a CPAP machine for a patient with sleep apnea.  Discussing all the symptoms and lifestyle choices you make will help your physician determine what testing is most appropriate to help properly diagnose and potentially treat your sleeping problem.

Contact Dr. Levy to find out if a sleep study is right for you.