EEG (electroencephalogram)
About this test
An electroencephalogram (EEG) is a test that measures electrical activity in the brain. This test also is called an EEG. The test uses small, metal discs called electrodes that attach to the scalp. Brain cells communicate via electrical impulses, and this activity shows up as wavy lines on an EEG recording. Brain cells are active all the time, even during sleep.
Why it's done
An EEG can find changes in brain activity that might aid in diagnosing brain conditions, especially epilepsy or another seizure condition. An EEG also might be helpful for diagnosing or treating: Brain tumors. Brain damage from a head injury. Brain disease that can have a variety of causes, known as encephalopathy. Inflammation of the brain, such as herpes encephalitis. Stroke. Sleep conditions. Creutzfeldt-Jakob disease. An EEG also might be used to confirm brain death in someone in a coma. A continuous EEG is used to help find the right level of anesthesia for someone in a medically induced coma.
Risks and complications
EEGs are safe and painless. Sometimes seizures are intentionally triggered in people with epilepsy during the test, but appropriate medical care is provided if needed.
How to prepare
Take your usual medicines unless your care team tells you not to take them.
Understanding your results
Doctors trained to analyze EEGs interpret the recording and send the results to the healthcare professional who ordered the EEG. You might need to schedule an office appointment to discuss the results of the test. If possible, bring along a family member or friend to the appointment to help you remember the information you're given. Write down questions to ask your healthcare professional, such as: Based on the results, what are my next steps? What follow-up, if any, do I need? Are there factors that might have affected the results of this test in some way? Will I need to repeat the test?
Disclaimer: August is a health information platform and its responses don't constitute medical advise. Always consult with a licenced medical professional near you before making any changes.