Sleep Studies and How Doctors Diagnose Sleep Apnea

If your doctor suspects you have obstructive sleep apnea without other serious health conditions, such as heart disease or lung problems, they may prescribe a portable sleep test device to use at home, says Robson Capasso, MD, chief of sleep surgery and a professor of otolaryngology and head and neck surgery at Stanford University School of Medicine in California.

These tests monitor your breathing and measure any pauses in breathing while you sleep.

If the test shows that you have sleep apnea, your doctor may be able to prescribe treatment without further testing. But if test results are normal and indicate that you do not have sleep apnea, your doctor may prescribe polysomnography, which is done at a lab, because home monitoring devices aren’t able to detect all cases of sleep apnea, says Dr. Capasso.

During polysomnography, your sleep cycles and stages will be monitored and recorded with removable sensors placed on your scalp, eyelids, chest, limbs, and a finger. These sensors will measure your body movements, brain activity, and breathing patterns to give your doctor an in-depth look at the quality of your sleep. Types of sensors that may be used include:

• Electroencephalography (EEG) Stuck to your head to track the electrical activity of the brain (brain waves) during the different stages of sleep
• Electrocardiography (EKG OR ECG) Worn on the chest to pick up the electrical activity of the heart
• Electromyogram (EMG) Attached to the face and leg to track muscle movement
• Electrooculography (EOG) Placed around the eyes to detect eye activity
• Respiratory Inductive Plethysmography (RIP) Belt Measures the effort of your breathing by tracking the expansion of your chest and abdomen
• Breathing Sensors Measure how well air flows in and out of your lungs through your mouth and nose
• Pulse Oximeter Placed on an index finger to read your pulse and the oxygen level in your blood

Most sleep centers have comfortable rooms modeled after those in hotels. Usually only one night is needed. You will most likely be asked to arrive a few hours before bedtime.

Trained healthcare providers will monitor you as you sleep, and in some cases, a video camera may record your movements. The camera is there only to alert trained staff if unusual activity is happening. So, unless there is a reason, you are most likely not being watched as you sleep.