An electroencephalogram (EEG) is a test that measures electrical activity in the brain. It is used to evaluate brain function and to diagnose a variety of conditions, including epilepsy, seizures, sleep disorders, and brain tumors.

How Does an EEG Work?

An EEG works by recording the electrical signals produced by the brain. These signals are then amplified and displayed on a computer screen. The patterns of brain activity can be used to diagnose a variety of conditions.

When is an EEG Test Done?

An EEG test may be done for a variety of reasons. Some of the most common reasons include:

• To diagnose epilepsy or seizures
• To evaluate brain function after a head injury or stroke
• To diagnose sleep disorders, such as narcolepsy or sleep apnea
• To help diagnose brain tumors
• To monitor brain activity during surgery

What Happens During an EEG Test?

During an EEG test, you will be asked to sit or lie down in a comfortable position. A technician will then apply small electrodes to your scalp. These electrodes are connected to a computer that records the electrical signals produced by your brain.

The EEG test usually takes about 30 minutes to an hour. During the test, you may be asked to do certain things, such as open and close your eyes, look at a light, or listen to music.

What Are the Risks of an EEG Test?

An EEG test is generally considered to be a safe procedure. However, there are a few potential risks, including:

• Skin irritation from the electrodes
• Headache
• Nausea

What Do the Results of an EEG Test Mean?

The results of an EEG test can be used to diagnose a variety of conditions. The patterns of brain activity can help doctors to identify areas of the brain that are not functioning properly.

If you have an EEG test, your doctor will discuss the results with you and explain what they mean.

Headings

• What is an EEG Test?
• How Does an EEG Work?
• When is an EEG Test Done?
• What Happens During an EEG Test?
• What Are the Risks of an EEG Test?
• What Do the Results of an EEG Test Mean?

Frequently Asked Questions

• Is an EEG test painful?

No, an EEG test is not painful. You may feel some discomfort from the electrodes being applied to your scalp, but this should be minimal.

• How long does an EEG test take?

An EEG test usually takes about 30 minutes to an hour.

• What should I wear to an EEG test?

You should wear comfortable clothing to an EEG test. You may be asked to remove your shoes and jewelry.

• Can I eat or drink before an EEG test?

You can eat and drink before an EEG test, but you should avoid eating or drinking anything with caffeine or alcohol for at least four hours before the test.

• What happens after an EEG test?

After an EEG test, you will be able to go home and resume your normal activities. Your doctor will discuss the results of the test with you at a later appointment.