Polysomnography (PSG) – A Sleep Study.

If your symptoms and signs have suggested that you may be having a sleep disorder, your sleep doctor will suggest a polysomnogram to confirm the diagnosis. A sleep study called polysomnography (PSG) is the most accurate method to diagnose a sleep disorder like sleep apnea.

It measures a number of physical and physiological activities while you are asleep.  It also monitors your sleep stages and patterns to see if your sleep cycle is disrupted during sleep.

Polysomnography, also called nocturnal polysomnography, is the most common sleep study which also records your breathing when you are sleeping. 

Polysomnogram.

The polysomnography equipment is called a polysomnogram. Surface electrodes are put on your scalp and face which send signals of brain and muscle activity to a measuring machine which records this digitally. Belts are wrapped around the chest and abdomen to record your breathing. PSG records various  physiological activities, the results of which help the doctor to arrive at a diagnosis of your sleep disorder.

Polysomnography Procedure and Results.

Polysomnography is an overnight study and is painless. It is usually done at a sleep center overnight where you may have to spend about 6 hours. The following physiological activities in your body are recorded during polysomnography.

• Brain activity is measured with EEG (electroencephalogram) Read sleep cycle to know brain activity which is measured in the form of brain waves by the EEG and which tells if your sleep consists of all stages of the sleep cycle or whether it is disturbed. Disruptions in sleep stages may suggest narcolepsy or REM sleep behavior disorder.
• Eye movements are recorded with a EOG (electro-oculargram). This helps to determine the presence of sleep stages particularly REM sleep stage.
• Muscle activity such as face twitches, teeth grinding and leg movements, is measured by EMG (electromyogram). This helps to determine if the REM sleep is present during sleep. Frequent leg movements may indicate a periodic limb disorder such as restless leg syndrome which is a sleep disorder because these movements often disrupt your sleep.
• Airflow in and out of the lungs while you are asleep is measured with a nasal airflow sensor.
• Snoring activity is measured with the help of snoring microphone. Very loud snoring is indicative of sleep apnea
• The percentage of oxygen in your blood is measured (oxymetry) by a bandage like oxymeter probe or sleeve that fits painlessly on one of your fingers. Low oxygen levels may indicate a sleep apnea.

The results of all these sleep study tests are then evaluated by a sleep specialist to come to diagnosis of a sleep disorder.

Picture of polysomnography procedure.

Indications for Polysomnography.

Poysomnography is done to diagnose whether the following sleep disorders and conditions are present or not.

• Sleep apnea
• Restless leg syndrome where you involuntarily flex and extend your lower limbs in your sleep.
• Narcolepsy which is associated with extreme daytime drowsiness.
• Chronic insomnia where the cause is not being diagnosed
• Unusual activity during sleep such sleep walking.
• REM sleep disorder where your dreams are acted out.

Complications.

  Polysomnography is a non invasive test in which the surface electrodes are used. Complications are rare and may consist of slight skin irritation at the site where the electrodes are placed.

Related posts:

1. How is Sleep Apnea Diagnosed.
2. NREM Sleep – Non Rapid Eye Movement Sleep.
3. Proper Bedroom and Bed to Sleep Better.
4. UPPP – Sleep Apnea Surgery.
5. Sleep Aids To Help You Sleep.
6. Over The Counter and Natural Sleep Aids to Help You Sleep.
7. Apnea and Sleep Apnea – A Dangerous Sleep Disorder.
8. REM Sleep – The Dreamer’s Sleep.