An EEG (electroencephalogram) measures your brain’s activity. Brain activity can help your healthcare provider diagnose and monitor brain-related conditions like epilepsy. Your healthcare provider may order an EEG if you have symptoms such as seizures or confusion. An EEG is safe and painless.
An EEG (electroencephalogram) measures and records your brain’s electrical signals. During an EEG, a technician places small metal disks (electrodes) on your scalp. The electrodes attach to a machine that gives your healthcare provider information about your brain’s activity. Brain activity can help your provider diagnose and monitor conditions that affect your brain.
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Most commonly, healthcare providers use an EEG to check for seizure activity related to epilepsy. EEGs can also help monitor health conditions or find out what’s causing certain symptoms.
Healthcare providers may use an EEG during brain surgery or to test the brain activity of someone in a coma.
EEGs can also check the status of brain-related conditions such as:
EEGs help diagnose the causes of symptoms such as:
A specially trained EEG technician performs the procedure. You may have an EEG in an outpatient laboratory or inpatient per your healthcare provider’s order. Some EEG tests record your brain’s activity while you go about your usual activities with an ambulatory device.
There are several types of EEG tests:
Electrodes on your scalp measure electrical signals (impulses) as they travel between brain cells. Electrodes are small metal disks that a technician secures to your scalp with removable glue.
Electrodes attach to wires that sense nerve signals, which are electrical impulses. The electrodes send information about the signals to an EEG machine.
The EEG machine records the impulses with lines (traces) that show brain wave patterns. The brain has specific wave patterns when you’re awake and asleep. If you have a seizure, the wave patterns change.
To prepare for an EEG, you:
Here’s what happens during an EEG:
After your EEG, the technician will remove the electrodes and clean your scalp. Your hair and skin may feel sticky, so you’ll want to wash your hair at home. You can drive and return to your usual activities unless your healthcare provider says you shouldn’t.
Some people may feel dizzy when they deep breathe during the EEG.
There is a small risk of seizure during an EEG. If this happens, your healthcare provider is there to help.
You will find out the results of your EEG at a follow-up appointment. Your healthcare provider will explain your EEG results to you.
Your healthcare provider will review the brain wave patterns that your EEG identified. The test results describe patterns as normal or abnormal.
Abnormal patterns have different causes, such as:
Your healthcare provider may refer you to a specialist, like a neurologist. A specialist can diagnose, treat or manage your condition.
An EEG (electroencephalogram) is a safe, painless test that measures brain activity. An EEG can help your healthcare provider learn the cause of symptoms like seizures, confusion or memory loss. With a diagnosis, your provider can treat and manage a brain-related condition appropriately.
Last reviewed by a Cleveland Clinic medical professional on 02/24/2021.
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