What to expect when getting an electroencephalogram
Anelectroencephalogram(EEG) test is used to check forseizuresand diagnoseepilepsy.
An EEG records electrical activity in the brain.
An EEG can be used by primary care providers or specialists like aneurologist.
Illustration by Cindy Chung, Verywell
This article covers uses for EEG, how they work, and what to expect during the test.
What Is an EEG Test?
There are several types of electroencephalograms (EEGs) and different versions of each key in.
The throw in you have done will depend on why you need the test.
Ideally, the test should be done within 24 hours.
It can be done with video as long as there is another person to do the taping.
Electrodes can be wireless or have wires that attach to a computer.
Brain waves are recorded as squiggly lines calledtraces, and each trace represents a different area in the brain.
EEG Uses
An EEG measures the continuous electrical activity of the brain.
EEGs most often are used to look for seizure activity or evaluate a persons risk for seizures.
If you’re being evaluated for epilepsy, your neurologist will look for patterns on your EEG calledepileptiform.
An EEG can be done with a standard sleep study (polysomnogram).
The electrodes used for an EEG are harmless because they only pick up electrical charges.
They do not emit electricity.
In rare cases, an EEG can cause seizures in a person with a seizure disorder.
In these cases, the seizures are brought on by deep breathing or flashing lights.
They can also happen if the person took less or none of their medication before they had the test.
There will also be oxygen and other safety equipment nearby in case you have a prolonged seizure.
Timing
The length of the encephalogram will depend on the pop in of test you’re having.
This time ensures that brain waves can be measured during sleep (a prolonged or 24-hour EEG).
An ambulatory EEG can be as short as a day or up to three days long.
If extended monitoring is needed, you might be admitted to the hospital for a few days.
If you have an ambulatory EEG, the test will take place at your home.
If you’re being admitted to the hospital, youll change into a gown to wear while youre there.
Caffeine can affect the results of the test.
You do not need to fast the night before or the day of your test.
ensure to follow your healthcare provider’s instructions about medications on the day of your test.
An ambulatory EEG typically runs from $500 to more than $3,000.
The average cost is around $780.
you’re able to also arrange for someone to pick you up when the test is over.
You might be able to use your cell phone, tablet, or laptop, but ask first.
Do not use conditioner, hairspray, or other styling products, as these could affect the electrodes.
You will then be taken to a testing room where a technician will do the EEG.
If you’re at a hospital, you might be admitted to an epilepsy monitoring unit.
The room where the test takes place will be quiet and dimly lit to help you relax.
Sometimes, a sedative is given to help you feel more comfortable.
The technician will have you either sit back in a reclining chair or lie down on a bed.
Next, the technician will attach the electrodes to your head, around 16 to 25 in total.
They may gently scrub each area where an electrode will be placed with a cream that’s mildly abrasive.
This helps the disc stick better and also improves the quality of the recording.
Sometimes, a cap with the electrodes already attached to it will be used instead.
Once the electrodes are in place, the technician will have you close your eyes and relax.
They may suggest you take deep breaths.
You will need to be still for an initial reading at rest.
You might be exposed to bright or flashing lights or noise.
The entire process should take between 45 minutes and two hours.
Post-Test
When the recording is complete, the technician will gently remove the electrodes from your scalp.
Otherwise, you should be able to go back to your regular activities after the test is over.
It can be removed easily with acetone or a similar solution after the test is done.
Your head will be covered with gauze or a cap during the test.
It can be worn on your waist with the wires running inside or outside of your shirt.
After the Test
you might go back to your normal activities after your test is done.
You’ll probably want to wash your hair to get rid of any remaining glue.
What Do the EEG Results Mean?
The results of your EEG will be sent to a neurologist to be read.
They will tell the provider who ordered your EEG what the test showed.
An EEG will come back as either normal or abnormal.
However, it is possible to get normal results even if you have a history of seizures or epilepsy.
For example, epilepsy can usually bemanaged with medication or surgery.
Summary
An EEG is a test that records the electrical activity in your brain.
There are two types of EEGs.
A routine EEG is typically performed within 24 hours of your first seizure.
An ambulatory EEG is a longer test that monitors brain wave activity over time.
Your provider will talk to you about the next steps after an EEG based on your diagnosis.
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Epilepsy Foundation of America.Which EEG punch in is best?
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Epilepsy Foundation of America.Electroencephalography (EEG).
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Stanford Health.Electroencephalogram for vascular dementia.
2014;121(1):59-69. doi:10.1007/s00702-013-1070-5
Johns Hopkins Medicine.Electroencephalogram (EEG).
University of Rochester Medical Center.Electroencephalogram (EEG).
Icahn School of Medicine at Mount Sinai.EEG.
