Polysomnography (PSG): Procedure, Parameters, Cost & Report Explained

What is Polysomnography(PSG) ?

Polysomnography is a diagnostic sleep study test which is used to diagnose the sleep related disorders. Polysomnography { Poly ( Many ) + Somno ( During Night ) + Graphy ( Checking ) } means checking of multiple parameters during sleep. PSG is short form generally used for Polysomnography sleep study test.

What is overnight polysomnography?

This is a diagnostic sleep study procedure which is performed for one full night to check the sleep pattern of patient. Since it is a sleep related check up so it is bound to be done during night for most of the people (except the people who sleeps during the day due to any shift job).

What are the types of polysomnography  (PSG) test ?

There are two types of Polysomnography (PSG) which are known as 

Level 1 sleep study or Level 1 Polysomnography (PSG)

Level 2 sleep study or Level 2 Polysomnography (PSG)

What is the procedure for different types of Polysomnography (PSG) sleep study test ?

Level 1 Sleep Study or Level 1 Polysomnography:

Level 1 PSG sleep study is performed in hospital or a dedicated sleep lab. This type of Polysomnography is known as gold standard of sleep study. This is a full sleep study which helps to diagnose maximum type of sleep disorders. It’s an overnight polysomnography where a technician checks about the sleep pattern live on the system and manually adjust the settings. Patient will have to get admitted to hospital or go to sleep lab for this type of test and sleep there only. Once the test is done then technician/Dr prepares a report and sign it. 

You can expect the report within 6-12 Hrs of test.

Level 2 Sleep Study or Level 2 Polysomnography:

Level  2 diagnostic sleep study is a step-down test of Level 1 Polysomnography. Level 2 sleep study /Level 2 Polysomnography sleep study can be done at home of the patient. A technician can come to patient’s place with a sleep study machine and hooks up the device on patient’s body. Patient can sleep in his/her bedroom with the device. Generally data is not recorded live in this type of Polysomnography. Sleep patterns are recorded in the device and technician will take the device back with him in the morning. After assessing the data captured in the Polysomnography device a report will be prepared. 

What are the differentiating factors of Level 1 and Level2 Sleep Study (Polysomnography)?

What are the key diagnostic parts of Level 1 Polysomnography & Level 2 Polysomnography?

What Does Polysomnography/PSG Measure? 

Level 2 sleep study or Polysomnography measures very important and key parameters during sleep –

EEG (to check Brain Activity): 

EEG stands for Electroencephalography and this helps to measure electrical activity in the brain during sleep. 

This helps to check sleep latency (Onset of sleep) and time taken from onset of sleep to REM sleep. Other key parameters like total sleep time, sleep stages N1 , N2 (light sleep), N3 (slow wave sleep) & REM sleep. EEG helps to check the wake period also during total time in bed. 

EOG (to check eye movements):

EOG stands for Electrooculography and this helps to measure the eye movement during sleep. 

It helps to check the REM sleep as we dream in REM sleep and eye movements increases during this stage. 

EMG(to check muscle activity): 

EMG stands for Electromyography and this helps to check the muscle activity on chin and legs. 

This helps to check any muscle activity in REM sleep , Bruxism & restless legs movement.

ECG(to check heart activity): 

ECG stands for electrocardiogram which helps to check the heart activity during sleep. 

This helps to identify arrythmia episodes during sleep.

Airflow ( to check nasal airflow ) 

A nasal cannula is used to check airflow which helps to identify snoring, flow limitations, apnea , hypopnea etc.  Apnea and Hypopnea readings are important part of AHI score. 

Respiratory effort (to differentiate the apnea)

An effort belt is used to check the respiratory effort which can help to differentiate between a obstructive apnea and central apnea. 

Oxygen saturation

Spo2 probe or oximetry helps to check the blood oxygen levels during sleep. This helps to know the lowest oxygen level drop during sleep. 

Body Position

A person can sleep in different position and apnea severity might depend on the position. 

Body position can be supine, left lateral, right lateral, prone. Generally, most of OSA episodes occur on supine body position. 

Leg Movements (to check the limb movements)

Sometimes the leg movements during sleep might cause arousal which is not normal.

Also Read:

• Sleep Study Test: Cost, Types, Procedure, Machines & Complete Guide
• Home Sleep Study: Cost, Procedure, Equipment & Accuracy Guide
• Sleep Apnea Test: Types, Procedure, Cost & Diagnosis Process
• Sleep Study Test Cost: Pricing, Factors & Insurance Information

What are the key parameters observed in Level 1 Polysomnography & Level 2 Polysomnography?

What Does a Polysomnography/PSG Report Include?

A Polysomnography/PSG/Level 2 Sleep Study report gives a comprehensive analysis of sleep which has details of important parameters of sleep like – 

Total Sleep Time : 

How many hours patient’s mind was in sleeping stage . Patient might be in bed for 8 Hrs but brain may sleep for 6 Hrs only , this can be seen in sleep study report. 

Sleep Latency:

After going in to bed what was the time taken by brain to reach in N1 sleep stage from wake stage. 

REM Sleep Latency :

After onset on sleep how much time was taken by brain to go into REM sleep, which is on of the deep stages of sleep. 

Sleep Stages:

Sleep is consist of Wake , N1,N2,N3 & REM stage , a Polysomnography sleep study report shows the bifurcation of time spent in each stage . Generally people with obstructive sleep apnea don’t go to N3 and REM sleep for sufficient time. 

Snoring: 

How many times snoring episodes were there during sleep.

Obstructive Sleep Apnea: 

How many times there was a complete obstruction in airway during sleep, what was the hourly average. 

We can check the longest duration apnea as well. 

Central Sleep Apnea :

How many times there was a loss of central drive to beath in , what was the hourly average of central sleep apnea.

Mixed Apnea:

Sometimes people may have a combination of obstructive sleep apnea and central sleep apnea which is known as mixed sleep apnea. In PSG sleep study report number of Mixed Apneas can be checked and what was their hourly average. 

Hypoapnea:

Hypoapnea is 30% reduction in airflow with 3% drop in O2 saturation. A polysomnography report helps to know the number of hypopnea and their hourly average. 

AHI:

This is known as Apnea Hypopnea Index and this is one the key diagnostic parameter to check the severity of obstructive sleep apnea. This is a combination of hourly average of Apnea and Hypopnea episodes during total sleep. 

Body Position:

This helps to know the time spent in different body positions during sleep like supine, right lateral, left lateral. 

Due to obstructive sleep apnea body forces to change the position.

Oxygen Desaturation:

This helps to know the oxygen levels during sleep, if there are any desaturations due to apnea then it gets recorded, Oxygen desaturation index is hourly desaturation of oxygen during sleep.

Arousals: 

Due to any reason if there is any arousal then that is also reported in PSG sleep study report. Arousal can be due to apnea , bruxism , leg movement etc. 

Bruxism: 

Bruxism is also known as teeth grinding during sleep. People may grind their teeth which might cause jaw pain. PSG sleep study report shows hourly average of Bruxism episodes. 

Leg Movements:

Limb Movement during sleep is a disorder which may cause arousal and disturbance in sleep. PLMs Index  is hourly average of leg movements.

Arrhythmia index:

This shows bradycardia and tachycardia episodes and their hourly average. This is recoded thru ECG during sleep. 

CPAP/Bilevel pressure: 

When there is pressure titration is part of process then CPAP/bilevel pressure can be checked on Polysomnography sleep study report which is a very important parameter from a sleep study report. 

Video recording: 

For some sleep disorders when video recording is done then it can be part of Polysomnography sleep study report. 

What Can PSG Diagnose?

A Polysomnography/PSG/Level 2 sleep study report can diagnose Obstructive Sleep Apnea , Central Sleep Apnea, Bruxism ( teeth grinding ) , Narcolepsy , Hypersomnia , REM related behavioural disorder etc.

Who Performs a PSG Test?

PSG/Polysomnography/Level 2 Sleep study can be performed by a trained or qualified technician for sleep study. In India there are very limited structured courses for sleep technician. In most of the cases sleep technicians are trained by PSG companies or qualified Drs. 

What is the cost of Level 1 PSG sleep study & Level 2 PSG sleep study?

Is Polysomnography as 32 channel sleep study ?

As per the definition any sleep study device which has minimum 7 channels comes under polysomnography.

Different companies might have different number of channels. 

What to see in full night sleep study or polysomnography sleep study test ?

There are some key parameters which should be checked in sleep study report – 

FAQs

• Is there any special preparation like avoiding medicine , fasting etc for Polysomnography ?

Ideally patient should follow their routine except excessive sleep during the day or excessive caffeine before 3 Hrs of Polysomnography. 

• How much time it takes to get the Polysomnography report ?

It may depend upon your service provider or hospital, However you may expect it within 6 – 24 Hrs after polysomnography test.

• If I need CPAP machine then will it part of Polysomnography report and cost ?

CPAP pressure can be part of sleep study report but CPAP is a different device and cost of CPAP is completely extra other than the Polysomnography report cost.

• Can I get any type of discount if Dr suggests for Split Night Polysomnography ?

Your hospital and service provider can explain if the procedure is split night or a full night diagnosis. Accordingly you can get a price quotation. 

• Is there any specific charge to understand the Polysomnography/PSG/Level 2 sleep study report ?

No, generally there are no specific charges for any counselling to understand the polysomnography report. 

Book/Schedule a Sleep Study (Polysomnography) from BreatheNest

You can book a Polysomnography/PSG/Level 2 Sleep Study  with BreatheNest for Delhi, Noida,Gurugram, Faridabad,Ghaziabad. BreatheNest is expert in sleep and respiratory devices. 

We offers a Polysomnography with one of the best machine’s in the world ( German Sleep Study Machine ) by  trained technicians. BreatheNest offers counselling support to understand the Polysomnography Procedure and report interpretation. We offer report within 6-10 Hrs of test completion.