Sleep Study

Sleep study is a comprehensive test used to diagnose sleep disorders. The medical term for sleep study is polysomnography. It is a non-invasive exam that records your brain waves, oxygen level in your blood, heart rate and breathing, as well as eye and leg movements during the study.

A sleep study helps in the diagnosis of various sleep disorders like sleep apnea, periodic limb movement disorder, narcolepsy, restless legs syndrome, insomnia, and nighttime behaviors like sleepwalking and REM sleep behavior disorder. An overnight stay at a sleep unit is required to conduct the test. While you are asleep your sleep stages and cycles are monitored to identify your sleep patterns and disruptions. An ENT doctor takes into consideration your symptoms and uses sleep study as an integral part of investigation into whether you face disrupted sleep.

Obstructive Sleep Apnea

In simple terms, obstructive sleep apnea (OSA) is when a person’s breathing stops during sleep because the airway collapses and prevents air from getting into the lungs.

OSA is the most common sleep-related breathing disorder. It usually starts with snoring, when the air can’t flow easily through the mouth or nose. During OSA the muscles at the back of the throat relax too much to allow normal breathing, causing the airway to narrow or close hampering the breathing for 10 seconds or more. This causes the oxygen levels in the body to fall.  The brain recognizes that it is not getting enough oxygen and rouses the person from sleep so that you can reopen the airway.

Such episodes can occur 5 to 30 times or more every hour all night long. These disruptions impair your ability to reach deep, restful sleep phases. Sleep apnea occurs in about 25% of men and nearly 10% of women. It can occur at any age but people over 50 and overweight people are more susceptible. If left untreated, OSA can result in hypertension, stroke, diabetes etc. An ENT specialist will do a physical examination of the back of the throat, mouth and nose for extra tissue or abnormalities note your symptoms and advise an appropriate course of action. Lifestyle changes, mechanical therapy, surgery are some of the ways of managing OSA.

An overnight stay at the sleep study unit or center is needed. Prior to the study a technician will place sensors on your face, scalp, chest and legs. These sensors record brainwave activity (to assess sleep stage), eye movements, muscle activity, heart rhythm, body movements, nasal/oral airflow, respiratory effort and oxygenation. In addition, a video camera will also be used to study your body position as you sleep. The sensors are harmless and cause no pain.

The normal process of falling asleep begins with a sleep stage called non-rapid eye movement (NREM) sleep. During this stage, brain waves slow down considerably. After an hour or two of NREM sleep, brain activity picks up again, and rapid eye movement (REM) sleep begins. Most dreaming occurs during REM sleep. Normally, multiple sleep cycles of switching between NREM and REM happen throughout the night. Sleep disorders such as sleep apnea, periodic limb movement disorder, narcolepsy, restless legs syndrome, insomnia, and nighttime behaviors like sleepwalking, disturb the sleep pattern. 

Yes. There are 2 main types.

  • Obstructive Sleep Apnea (OSA): This is the most common type of apnea. OSA occurs when a person’s airway becomes partially or completely blocked repeatedly while they sleep. This causes the breathing to become abnormally shallow or absent as the diaphragm and chest muscles work harder open the airway. Breathing usually resumes with a loud gasp or body jerk.
  • Central Sleep Apnea (CSA): In this type the airway is not blocked but the brain center, the brain stem, which controls a person’s breathing fails to signal the muscles to breathe. 

Snoring is common and almost everyone snores on occasion. It does not mean that one has obstructive sleep apnea. Even though both are closely related but they are not identical. Not all patients who snore have sleep apnea but all patients who suffer from obstructive sleep apnea will count loud snoring as one of its major symptoms. 

Sleep apnea is just not a bad night’s sleep but much more. Sleep is crucial for one’s mental and physical health. A restless night’s sleep can impact your mood and work performance the next day. You can feel lethargic and may have memory problems. Sleep apnea can give rise to dangerous long-term maladies like high blood pressure and heart problems because during an apneic episode the body experiences drops in oxygen. This puts a strain on the cardiovascular system damaging the heart. It can also increase your risk of becoming insulin-resistant and developing type-2 diabetes.