Memorial Hermann Sleep Centers perform Polysomnograms (overnight sleep studies), Multiple Sleep Latency Tests (MSLT), and Maintenance Wakefulness Tests and Home Sleep Testing (HST) for the diagnosis of sleep disorders.
Overnight Sleep Studies
Memorial Hermann performs the following overnight studies (daytime tests may be scheduled for shift workers):
Nocturnal Polysomnogram
The nocturnal polysomnogram (NPSG) is considered the “gold standard” tool for diagnosing sleep disorders. The NPSG is commonly ordered for patients with:
- Excessive daytime sleepiness
- Snoring
- Sleep apnea
- Insomnia
- Morning headaches
- Chronic fatigue
- REM behavior disorder
- Parasomnias that include night terrors, nightmares, sleep walking and bed wetting
Nocturnal Polysomnogram with CPAP
The NPSG with continuous positive airway pressure (CPAP) is performed for the treatment of obstructive and mixed sleep apnea, upper airway resistance syndrome and snoring.
- CPAP systems consist of an airflow generator, air tubing and a nasal mask. Air pushed from the generator through the tubing and mask passes through your nose and into your throat, where the slight pressure keeps your upper airway open without interfering with breathing. CPAP is considered the most effective noninvasive treatment for obstructive sleep apnea (OSA).
Nocturnal Polysomnogram with BiPAP
The NPSG with BiPAP is performed with people who have difficulty tolerating the NPSG with CPAP or for those who have a CPAP pressure of higher than 17 cm/H2O.
Bilevel therapy works by delivering two different levels of positive air pressure: a higher level of pressure when you inhale and a lower level of pressure when you exhale. BiPAP devices can help people with obstructive sleep apnea (OSA) if they have found CPAP therapy too difficult.
Split Night Sleep Study
The split night sleep study is used to initiate quick treatment for severe obstructive sleep apnea (OSA). The study consists of two parts: diagnostic tests are performed during the first half of the night and if obstructive sleep apnea is clearly evident, treatment involving the nasal CPAP is administered during the second half of the night.
Multiple Sleep Latency Test (MSLT)
During a multiple sleep latency test, a specialist (or technician?) will record your brain waves, eye movements, muscle activity and EKG (heart) activity during five 20-minute naps (scheduled throughout the day, in two-hour intervals).
Used to rule out narcolepsy, cataplexy and idiopathic hypersomnolence (excessive sleepiness), the MSLT can accurately assess daytime sleepiness by measuring the length of time required to fall asleep during each nap (sleep latency).
The MSLT also measures rapid eye movement (REM) sleep (or dreaming) and the latency (time it takes to achieve REM sleep) during each nap. By sampling sleep latency five times during the day, we can obtain a profile of your daytime sleepiness.
When is an MSLT Recommended?
An MSLT is recommended for people with complaints of excessive daytime sleepiness or for those with a history of falling asleep inappropriately during the day. An MSLT is especially important if your polysomnogram overnight study results were normal, but you continue to experience daytime sleepiness.
Usually, the MSLT is scheduled the day after the overnight study, in which case you'll remain in the hospital throughout the test (the entire night and the following day). Some of the electrodes used in your overnight study will be removed, while those on the head and around the eyes, chin and the chest will be left on for the MSLT.
Should I Stop Taking any Medications Before an MSLT?
Since an MSLT is very sensitive to certain types of medication, like stimulants or antidepressants, your physician will instruct you ahead-of-time on which medications you should, or should not take, before the study.
Should I Stay Awake Between Nap Periods?
It is important that you try to stay awake throughout the day of your test, except during nap periods. You may read, walk, eat regular meals (without caffeine) for the duration of your stay in the hospital. You may want to bring a book or something to keep you occupied during the day. Meals will be provided during the nap study.
Children's Sleep Studies
The highly-skilled specialists at the Pediatric Sleep Center at Children’s Memorial Hermann are dedicated to providing your child with the most advanced care using the latest technologies for the treatment of sleep-related disturbances . The Center's six bedrooms are designed to provide a comfortable sleep environment for your child, ensuring their comfort and the integrity of the test.
Sleep Study FAQs
If you or a loved one are exhibiting signs of a sleep disorder, the dedicated sleep specialists at Memorial Hermann can provide you with the answers you need to help you get back to a good night’s sleep.
Am I a Candidate For a Sleep Study?
Please answer the 8 questions below to help us assess for possible sleep apnea, a condition in which your breathing pauses or stops for periods of time while you sleep. Sleep apnea can increase your risk for many health conditions. It can also increase your risk for breathing problems after surgery. If you answer yes to 3 or more questions, you are at risk for sleep apnea. Your physician may ask that you be evaluated by a sleep physician. This is for your own safety.
STOP-BANG Questionnaire
- Snoring: Do you snore loudly (louder than talking or loud enough to be heard though closed doors)?
- Tiredness/fatigue: Do you often feel tired, fatigued, or sleepy during the daytime, even after a “good” night’s sleep?
- Observed apnea: Has anyone has ever observed you stop breathing during your sleep?
- Pressure: Do you have or are you being treated for high blood pressure?
- Body mass index: Do you weigh more for your height than is shown in the tables at right?
- Age: Are you older than 50 years?
- Neck size: Does your neck measure more than 15 inches (40 cm) around?
- Gender: Are you male?
Schedule a Sleep Study
If you or a loved one are showing signs of a sleep disorder, the dedicated sleep medicine specialists at Memorial Hermann can, if necessary, refer you for a sleep study. Once results from your sleep study are received and evaluated, the specialist will provide you with a diagnosis and treatment plan, and he or she will monitor your overall health throughout the treatment process.