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 An electroencephalogram (EEG) test involves the recording and analysis of electrical signals generated by the brain. There are two types of EEGs: routine and sleep-deprived.

Your physician would order this test for the following reasons:


  • To diagnose or rule out epilepsy
  • To investigate causes of a confusional state
  • Infectious disease (i.e. meningitis, herpes, encephalitis, Creutzfeld Jakob’s disease)
  • Developmental delay
  • Day dreaming
  • Follow-up EEG for management of epilepsy/cessation of medication
  • Sleep-deprived
  • When a routine EEG is normal but epilepsy is still suspected

Click here to view the EEG brochure.

Location and Contact Information

To make an EEG appointment, please visit the Make an Appointment page.

Markham Site

We suggest parking in the main hospital parking lot, opposite the Link Lobby Entrance and Medical Office Building, when visiting diagnostic services.

Please go to the central registration desk on the main floor of Building A, before heading to diagnostic services on the second floor in Building B where you'll be directed to the EEG waiting room.

For more information on parking, please click here.

Care Providers

An electroencephalogram is performed by an EEG technologist.

What You Should Know

For a routine or sleep-deprived EEG:
Shampoo your hair on the morning of the test. Do not use gel, mousse, sprays, etc. Bring all current medications with you. Have meals as usual but exclude caffeinated products. Caffeine products include: coffee and tea (decaffeinated and caffeinated), chocolate, cocoa, soda, pop and any medication or supplements that may have caffeine.  

For a sleep-deprived EEG:
Adults and children over 12 years of age must stay awake (for the entire night before the test) from midnight before your test.  You should book children 12 months to three years during their naptime. Four to eight year olds should be awake from 4 a.m., nine to 12-year-olds from 2 a.m.

Before Your Visit

Please wear comfortable clothing.

Please arrive 30 minutes before your test to register at the central registration desk in Building A. Please bring your health card and your requisition (if your physician has provided you with one).

During Your Visit

The approximate time for an EEG is 60 to 90 minutes.

For your test, you will be lying on a bed in a relaxed position. A technologist will measure and mark your head with a washable crayon and will then attach small disks to your scalp using a thick paste, to record tracings of brain wave activity. No needles are used in this procedure.

After Your Visit

There are no side effects from having this test; however, there will be paste in your hair that can be removed with a washcloth.

Frequently Asked Questions

How long will the test take?
The test will take between 60 and 90 minutes.

Do you use needles?
No, we attach small disks to your head with a thick paste.

Do you have to put that cream in my hair?
Yes, the cream is a paste that keeps the small disks on the scalp.

Are there any side effects to this test?

Is this electric shock treatment?

Is any radiation used in this test?

Additional Resources

Epilepsy and seizure information for patients and health professionals – epilepsy.com