Electro-Encephalogram (EEG)


What is an electro-encephalogram (EEG)?

An electro-encephalogram is a test that measures and records the electrical activity of the brain by using sensors (electrodes) attached to the head and connected by wires to a computer. This test tracks and records your child’s brain wave patterns. The computer will record the brain’s electrical activity and displays it in the form of wavy lines on a screen.

What are the benefits?

An EEG is used to help diagnose epilepsy and it can help diagnose seizures. It may also be used to diagnose or monitor the following health conditions:

  • Abnormal changes in body chemistry that affect the brain
  • Brain diseases
  • Altered mental status
  • Head injuries
  • Infections such as encephalitis or meningitis
  • Tumors

How do I prepare my child for the test?

  • Wash your child's hair using shampoo only on the night before the test, to keep their head clean and free of oils and sprays
  • Avoid using conditioner and spray as this may cause the electrode not to stick to your  child's head
  • Inform the doctor if your child has or being treated for head lice.
  • Stop giving your child food and drinks that contain caffeine (soft drinks, tea, chocolate) 8 hours before the test  
  • Your child should not be allowed to sleep on the day of the EEG as he/she will be required to sleep during the EEG test
  • Your child should sleep 4 hours less than usual the night before the EEG

How long does the test take?

EEGs can take up to 2 hours from the time the electrodes are placed on your child's head until the test is completed. If your child is required to sleep during the test, it may take longer.

How is if performed?

An EEG is a pain-free test. Your child will not feel any shocks on the scalp or elsewhere.
For the test, your child will be asked to lie on a bed. The EEG technician will attach electrodes to specific locations on the scalp using adhesive paste. The electrodes are then connected to an amplifier and EEG recording machine.
The electrical signals from the brain are converted into wavy lines on a computer screen.
Your child will be asked to lie still because movement can affect the recording.
At some point during the EEG, your child will be asked to look at flashes of flickering lights. Your child will also be asked to breathe fast by blowing on a pin wheel. This helps increase the information collected during the EEG recording. The technologist performing the EEG will know your child’s medical history and will be prepared for any issues that may arise during the test.

What are the risks?

EEGs are very safe. If your child has a seizure disorder, their doctor might want to provoke and record a seizure during the EEG. A seizure can be triggered by flashing lights or a change in breathing pattern.

When will I get the results?

Results from your child’s EEG test will be shared with you at your next doctor’s appointment or earlier if there are any concerns.