Electroencephalogram
Key points
- An electroencephalogram (EEG) is a test to detect abnormalities in the electrical activity of the brain.
- Brain cells communicate by producing tiny electrical impulses.
- You will need to wash your hair the night before the test.
- The preparation you can provide for this test depends on your child's age, previous experiences, and level of trust.
Alternative names
EEG; Brain wave test
Definition
An electroencephalogram (EEG) is a test to detect abnormalities in the electrical activity of the brain.
How the test is performed
Brain cells communicate by producing tiny electrical impulses. In an EEG, electrodes are placed on the scalp over multiple areas of the brain to detect and record patterns of electrical activity and check for abnormalities.
The test is performed by an EEG technician in a specially designed room that may be in your health care provider's office or at a hospital. You will be asked to lie on your back on a table or in a reclining chair.
The technician will apply between 16 and 25 flat metal discs (electrodes) in different positions on your scalp. The discs are held in place with a sticky paste. The electrodes are connected by wires to an amplifier and a recording machine.
The recording machine converts the electrical signals into a series of wavy lines that are drawn onto a moving piece of graph paper. You will need to lie still with your eyes closed because any movement can alter the results.
You may be asked to do certain things during the recording, such as breathe deeply and rapidly for several minutes or look at a bright flickering light.
How to prepare for the test
You will need to wash your hair the night before the test. Do not use any oils, sprays, or conditioner on your hair before this test.
Your health care provider may want you to discontinue some medications before the test. Do not change or stop medications without first consulting your health care provider.
You should avoid all foods containing caffeine for 8 hours before the test.
Sometimes it is necessary to sleep during the test, so you may be asked to reduce your sleep time the night before.
Infants and children:
The preparation you can provide for this test depends on your child's age, previous experiences, and level of trust. For general information regarding how you can prepare your child, see the following topics:
- Infant test or procedure preparation (birth to 1 year)
- Toddler test or procedure preparation (1 to 3 years)
- Preschooler test or procedure preparation (3 to 6 years)
- Schoolage test or procedure preparation (6 to 12 years)
- Adolescent test or procedure preparation (12 to 18 years)
Written and revised by
Andrey Nailor, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
health.am provides general information, not medical advice. Always consult a qualified health professional about your own health.