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Memorial Hermann Sleep Study FAQs

What is an overnight sleep study?

An overnight sleep study (nocturnal polysomnogram) is a recording of brain waves (EEG), eye movements, certain kinds of muscle activity, cardiac activity, respiratory activity, nasal and oral breathing, snoring and blood oxygen concentration during a regular night of sleep.

Why is an overnight sleep study necessary?

Doctors can learn a great deal about your sleep and waking patterns from a sleep study. An overnight study reveals information about sleep, including how many hours you actually slept, how often you woke up, what stages and depths of sleep you went through during the night and whether you had normal rapid eye movement (REM) sleep involving dreaming.

The study also permits grading of unusual muscle activity (such as muscle jerks), unusual brain activity (such as mild seizures), unusual cardiac activity, variations in blood oxygen concentration throughout the study and especially unusual respiratory activity (such as sleep apnea including the momentary stopping of breathing).

Is the test valid if I am not able to sleep in these unusual circumstances?

Yes. Most people do not sleep as well in a sleep center as they would at home. In most cases, we can still get the information we need, even if you don't sleep as well as you normally do.

Does it hurt?

No. We gather all the information we need through noninvasive surface contact electrodes. No needles are used, and there is nothing painful about the test.

How are the electrodes attached?

We use various types and sizes of surface electrodes, which are like small metal cups. Normally, we apply electrodes with non-allergic conductive paste and gauze pieces to several places on your head. No hair will be shaved. Electrodes are also attached to your chin, near the eyes, on the shoulder and to both shins. If we are recording your respiration, we'll ask you to wear a small probe around your nose and mouth.

Bands are placed around your chest and abdomen to measure breathing. Finally, we may apply a probe to your finger to measure the amount of oxygen in the blood. There is no pain, although occasionally, some patients consider the electrodes to be a nuisance or slightly uncomfortable.

For other questions please fill out the form on the right and we will contact you.