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Sleep deprived EEG

What is a Sleep Deprived EEG Recording?

A sleep EEG (electro-encephalogram) is the recording of electrical activity produced by the brain whilst you sleep.  It will help your doctor in making a diagnosis.  A sleep EEG is useful as it obtains different information to the routine EEG, as brainwave patterns change during drowsiness and sleep. 

How is it performed?

The appointment takes approximately 2 hours.  A physiologist will measure your head and apply a minimum of 25 small discs using a sticky paste.  Once in place a bandage may be used around your head to hold all the discs securely.  The setup procedure is not painful and you will not feel anything whilst the EEG is being recorded.  The recording time is usually an hour.  After the test the discs are removed, small residues of paste may be left in your hair which will wash out with shampoo.  We recommend you do not have a bath without someone in the house because you may still be drowsy.

How do I prepare for the test?

You need to be sleepy for the test.  The night before the recording you should have only HALF THE USUAL AMOUNT OF SLEEP.  For example if you normally sleep for 8 hours this should be reduced to 4 hours.  If you normally go to bed at 11pm then you need to get up at 3am.  We ask that you get out of bed and perform an absorbing task such as doing some housework.  Please be aware that if you were to stay in bed you could easily fall asleep again.

Please ensure your hair is clean and free from hairspray and oils.  Please wear loose fitting, comfortable clothing. 

If you are taking medication please continue to take it and bring a list of your medication with you.

Continue to eat meals as normal.

Please do not have drinks that contain caffeine, e.g. coffee, tea and cola or stimulant drinks (e.g. Red Bull) on the day of your test.

What else do I need to know?

A digital video recording will be made during the EEG recording.  This enables the doctor to compare your brainwaves with your movements and behaviour during the EEG.  However the test can be performed without the video if you prefer.  We will ask for your permission to use the video at the beginning of the test.

Are there any risks?

For some people sleep deprivation can increase the possibility of you having an attack.  If you have any questions regarding sleep deprivation please ask to speak to one of the Clinical Physiologists.  The telephone number is below.

How long will I have to wait?

You have been given a specific appointment time and patients are usually seen on time.  It is important that you arrive on time.  Please allow plenty of time for parking.

This test takes up to 2 hours to complete.

When will I get the results?

The results are sent to the doctor that referred you for the test and are usually available within seven days.


Neurophysiology Department   01422 222976

If you have any concerns or questions please speak to one of the Clinical Physiologists on the above number.