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You slept for seven hours last night, but today you still feel tired. Sometime overnight, your bed partner retreated to the couch, unable to tolerate your snoring and recurrent awakenings. Trouble is, you don’t remember a thing. All signs point to obstructive sleep apnea, characterized by brief halts in breathing and a collapse of your airway while you sleep. To be sure you get the right diagnosis, you might need a sleep study.
Today, a sleep study can be done at home or, for more complicated cases, in a special lab, where more comprehensive testing is available. Whatever route you choose, the key is to diagnose and treat what’s disrupting your shuteye so you can sleep better at night and function better during the day.
Why Worry About Sleep Problems?
If you have a sleep disorder, your troubles may transcend the realm of sleep. For example, insomnia has been associated with mood and memory disorders. Poor sleep can lead to excessive daytime sleepiness, which can affect your productivity, impair your mental and physical function, and reduce your alertness, thus making you more susceptible to motor vehicle accidents. And, research has identified correlations between obstructive sleep apnea and greater risks of high blood pressure, heart disease, stroke, abnormal heart rhythms, and other health maladies.
That’s why it’s vital to report any sleep problems to your primary care physician, who may refer you to a sleep specialist for further evaluation. Sleep disorders encompass a multitude of conditions, and identifying your particular sleep problem is critical for determining which testing and treatments you need. A sleep expert will ask you detailed questions about your sleep habits and may suggest you keep a sleep diary to document your sleep-wake patterns. If the physician suspects sleep apnea or certain other sleep disorders, you’ll be advised to undergo a sleep study.
Take a Sleep Study at Home
For years, the diagnostic standard for sleep apnea has been an overnight sleep study (polysomnography), in which you’re monitored at a lab while you sleep. Technical advances now allow for a more convenient way for patients with a high probability of sleep apnea to be diagnosed at home (use the STOP questionnaire, below, to gauge your likelihood of having sleep apnea).
A typical home sleep study includes a small, portable monitor, a belt encircling your midsection, a clip placed on your finger to measure your oxygen levels, and an airflow sensor placed under your nose. After you’ve completed the study, you’ll return the equipment to the sleep lab or other medical facility, where a sleep physician will review the results.
THE “STOP” QUESTIONNAIRE
Many physicians use the STOP questionnaire to help assess a person’s risk of obstructive sleep apnea. If you answer two or more of the following questions affirmatively, you are considered at high risk for sleep apnea:
- S: Do you Snore loudly (louder than talking or loud enough to be heard through closed doors)?
- T: Do you often feel Tired, fatigued, or sleepy during daytime?
- O: Has anyone Observed you stop breathing during your sleep?
- P: Do you have, or are you being treated for, high blood Pressure?
Guidelines from the American College of Physicians recommend home sleep studies as an option for diagnosing sleep apnea in patients without other serious diseases, such as certain lung, heart, and neurological disorders (Annals of Internal Medicine, Aug. 5, 2014). Nevertheless, an in-lab study might be necessary if you have one or more of these chronic diseases or if, despite the home study, questions remain about whether you have sleep apnea.
Understand that a home sleep study has limitations. It can identify sleep apnea, but it may underestimate its severity. While a home sleep study can measure your oxygen levels and heart rate and detect snoring, it doesn’t gauge certain other sleep characteristics or identify problems such as restless legs syndrome or periodic limb movement disorder (characterized by leg twitching while sleeping) like an in-lab study can do.
Also, if a home study diagnoses sleep apnea, you might require a follow-up in-lab study if you need to be fitted for treatment with continuous positive airway pressure (CPAP), a device that pumps air through your nose and/or mouth to keep your airway from collapsing. (However, many CPAP machines are automated to adjust to your individual characteristics, so you might not need follow-up testing in a sleep lab to tailor treatment.)
At the Sleep Lab
If you require an in-lab study, find out about the sleep lab in advance, including the conditions it is equipped to manage and what preparations you need to make. You might ask to tour the facility.
On the night of your sleep study, you’ll first meet with the technician to go over what to expect and to ask any questions. Since the lab isn’t like your sleep environment at home, wear your favorite sleep garments and bring your favorite pillow or blankets to feel more comfortable.
After you change into your bed clothes, the technician will attach a variety of sensors and wires all over your body to measure your heart rate, breathing, brain activity, oxygen level, and any leg movements. The technician will monitor you and your vital signs from another room. You’ll be permitted to read or take part in whatever activities you normally do at bedtime.
In general, an overnight sleep study lasts eight hours, although sometimes sleep apnea can be diagnosed based on just a few hours of total sleep time.
Some centers perform a split-night sleep study, in which a diagnosis of sleep apnea is made during the first part of the study, followed by CPAP treatment. This type of study allows the patient to leave the center not only with a diagnosis, but also with the information the doctor needs to determine how much CPAP pressure is needed to control sleep apnea. Expect the results of your sleep study to be delivered to your doctor within a few days to a week.
As a more comprehensive and labor-intensive process, an in-lab sleep study is costlier than a home study. Medicare and many other insurance providers will cover the cost if the study is done at a certified sleep lab, and they might cover home studies, as well. Check with your provider to find out which sleep tests and treatments your insurance covers.