Electroencephalogram Testing (EEG)


What is an EEG?

An electroencephalogram (EEG) is a test used to evaluate the electrical activity in the brain. Brain cells communicate with each other through electrical impulse. An EEG can be used to help detect potential problems associated with this activity.

The test tracks and records brain wave patterns. Small, flat metal discs called electrodes are attached to the scalp with wires, the electrodes analyze the electrical impulses in the brain and send signals to the computer where the results are recorded.

The electrical impulses in an EEG recording look like wavy lines with peaks and valleys. These lines allow the doctor to quickly assess whether there are abnormal patterns. Any irregularities may be a sign of seizure or other brain disorders.

Treated Conditions:

  • Headache
  • Seizure Disorders (such as Epilepsy)
  • Head Injury
  • Encephalitis (inflammation of the brain)
  • Brain Tumor
  • Encephalopathy (a disease that causes brain dysfunction)
  • Memory Problems
  • Sleep Disorders
  • Stroke
  • Dementia
  • Alzheimer’s
  • Multiple Sclerosis

Services Provided:

  • Electroencephalogram (EEG)
    • Both routine and ambulatory

EEG chart


Essential EEG Questions

What will happen during my EEG?

A routine EEG takes 45 minutes to complete. You will be seated in a comfortable chair and the EEG technician will attach the 20 electrodes to various parts of your scalp to measure the electrical activity in various parts of the brain. An additional 6 other reference and artifact detection electrodes, the brain puts out a small electrical impulse and these electrodes pick this up. To improve the conduction of these impulses a gel will be applied to the clean skin first, then a conductive paste will be used to attach the electrodes to the skin. You may feel some tingling from the gel but no pain will be involved.

The electrodes only read the impulses given off by the brain and do not transmit any stimulus to the brain. The technicians may ask you to breath quickly for a short period of time or use a flashing light to see if there are any changes in the brain waves during the EEG. You will also be asked to relax and try to take a nap, the more relaxed you are during the test the better the tracing will be.

When the test is complete the technician will remove the electrodes and get as much of the paste out of your hair as possible. The rest will wash out with warm water and shampoo.

How should I prepare for my EEG?

In preparation for the EEG you should wash and dry your hair the night before of the day of the test. Do not use any styling products afterwards. You can take all medications as prescribed, please avoid consuming any food or drink consuming caffeine at least eight hours prior to the test. You will be able to resume your daily activities immediately after the test.

If you are having a Sleep Deprived EEG you will be asked to sleep no more than 4 hours, the night before the test. Please follow the same preparation as above.

If you are having an Ambulatory Video EEG, you will be allowed to go home and resume normal activity with the scalp electrodes attached to a portable recorder for 48-72 hours. You will need to shower or bath, wash and dry your hair, again no styling products in your hair afterwards. Wear a button-down shirt as you will not be able to take clothing over your head once the electrodes are attached.

How long will the test take?

The test will take 45 minutes.

When will I get my results?

The same day.

Who does the testing?

The American Society of Electroneurodiatnostic Technologist, Inc set the national competency skill standards for performing and electroencephalogram. A properly trained EEG technician, under the guidance of the interpreting physician, will perform the test.