Testing and Diagnosis

CHAPTER 11

  

Testing and Diagnosis

PART 1

What Will Happen at the Doctor’s Office

If you suspect you have sleep apnea, either because of symptoms you’re experiencing during the day or because someone has noticed loud snoring, gasping, or pauses in your breathing at night, it’s a good idea to go to your doctor for testing and diagnosis. It’s surprising, but many people with even moderate-to-severe sleep apnea have no idea that they have OSA.

Gathering the Clues
Generally, your primary care doctor will evaluate your symptoms and, if it seems appropriate, refer you to a doctor who is a sleep specialist. These physicians may be ear, nose, and throat specialists, lung and nerve specialists, or other types of doctors. READ MORE

The sleep specialist will first take your medical history. He or she may ask if any of your relatives have sleep apnea and if anyone has told you that you snore, gasp or choke, or regularly stop breathing at night. Your doctor will inquire about your symptoms (for instance, being sleepy during the day, waking up with a dry mouth, or having trouble concentrating).

You’ll be given a physical examination that will include taking your blood pressure and examining your neck size. Your mouth, nose, and throat will be examined to see if your throat seems crowded and to check for a large tongue, uvula, or soft palate or enlarged tonsils and adenoids.

You may be asked to keep a sleep diary for 1-2 weeks. In a sleep diary, you write down both how much you sleep each night and your symptoms (like drowsiness) during the day.

If it seems likely that you have sleep apnea, your doctor may recommend that you have diagnostic polysomnography (see below), in which your sleep will be monitored overnight. LESS
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PART 2

Monitoring Your Sleep

The gold standard in testing for sleep apnea is polysomnography, in which you stay overnight at a sleep lab and your breathing patterns and other body functions are monitored. Some doctors use home monitoring instead of having you stay overnight at a lab. Polysomnography can confirm a suspected diagnosis of sleep apnea, or it may discover another type of sleep disorder.

A polysomnogram (PSG) measures your breathing patterns, brain activity, eye movements, arm and leg movements, heart rate, the amount of air that moves in and out of your lungs, and your blood oxygen levels while you sleep. Polysomnography is noninvasive: sensors are simply taped to your skin. READ MORE

Split Testing
If your doctor suspects you have sleep apnea, you may be given a split-night sleep study. In the first part of the night, you’ll be tested for sleep apnea. In the second part of the night, you’ll be monitored while using a continuous positive air pressure (CPAP) machine to see if the CPAP corrects the sleep apnea and what the best air-flow setting is for you.

Lab vs Home Testing
At-home testing for sleep disorders is becoming increasingly popular, and some doctors may provide you with a portable testing device to use in your own home. However, these machines don’t test as many of your body functions as a PSG and aren’t considered as reliable. LESS
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PART 3

Diagnosing Sleep Apnea

After sleep testing is completed, the information that’s been collected is analyzed by a sleep technologist. Sleep data is processed in 30-second chunks that include all the different body functions that were measured. The sleep specialist then reviews this data to make a diagnosis.

In diagnosing sleep apnea, the sleep specialist looks for the number of apneas and hypopneas you have per hour of sleep. These events are added up and averaged out. The result is what’s termed an apnea and hypopnea index (AHI), which shows the number of events per hour. READ MORE

Grading Sleep Apnea
Sleep apnea is graded as follows:

  • Mild sleep apnea: fewer than 15 events per hour

  • Moderate sleep apnea: 15-30 events per hour

  • Severe sleep apnea: More than 30 events per hour

However, sleep specialists look at the whole picture when grading sleep apnea. For instance, someone may be having only 18 events per hour, putting them in the “moderate” category. But if their oxygen level is going down 82% each time they have an apnea event, they may be diagnosed as having severe, not moderate, sleep apnea. LESS
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Photo attribution of Charles Dickens portrait
Copyright 2006 Project Gutenberg