Electroencephalogram (EEG)

An Electroencephalogram (EEG) is a non-invasive medical test used to evaluate the electrical activity of the brain. It is commonly used to diagnose and monitor conditions such as epilepsy, seizures, and other neurological disorders.

How it Works

The EEG test involves placing small electrodes on the scalp, typically 16-25 in number, which are connected to a machine that records the electrical activity of the brain. The electrodes detect the tiny electrical signals produced by the brain's neurons and transmit them to the machine, which amplifies and records the signals.

Types of EEG

There are several types of EEG tests, including:

  • Resting EEG: This is the most common type of EEG test, where the patient sits or lies down in a relaxed state with their eyes closed.
  • Sleep EEG: This test is used to evaluate brain activity during sleep and can help diagnose sleep disorders such as insomnia or sleep apnea.
  • Ambulatory EEG: This test involves wearing a portable EEG device for an extended period, usually 24-48 hours, to monitor brain activity during daily activities.
  • Video EEG: This test combines EEG with video recording to capture and analyze seizures or other abnormal brain activity.

Preparation and Procedure

To prepare for an EEG test, patients are typically asked to:

  • Wash their hair the night before to remove any styling products
  • Avoid using hair styling products on the day of the test
  • Arrive at least 30 minutes before the scheduled test time
  • Remove any metal objects, such as jewelry or glasses, that may interfere with the test

The EEG procedure typically takes 15-60 minutes to complete and involves:

  • Placing electrodes on the scalp
  • Adjusting the electrodes to ensure proper contact
  • Recording brain activity while the patient is at rest or performing specific tasks, such as reading or problem-solving

Risks and Side Effects

The EEG test is generally considered safe and painless. However, some patients may experience:

  • Mild discomfort or skin irritation from the electrodes
  • Dizziness or lightheadedness during the test
  • Seizures or other abnormal brain activity in rare cases

Interpretation of Results

The EEG results are interpreted by a qualified healthcare professional, typically a neurologist or epileptologist. The results can help diagnose and monitor conditions such as:

The EEG results can also help monitor the effectiveness of treatment and adjust medication as needed.

Frequently Asked Questions (FAQs)

What is an EEG?
A test measuring electrical activity in the brain.

Why is an EEG performed?
To diagnose and monitor neurological disorders.

How is an EEG done?
By attaching electrodes to the scalp.

Is an EEG painful?
No, it is a painless procedure.

How long does an EEG take?
Typically 15-60 minutes.

Do I need to prepare for an EEG?
Yes, wash your hair and avoid styling products.

Can I take my medications before an EEG?
Yes, unless instructed otherwise by your doctor.

Will I be awake during the EEG?
Yes, you will be awake and alert.

What will I experience during the EEG?
You may be asked to relax, sleep, or perform tasks.

Are EEG results available immediately?
No, results are typically reviewed and reported later.

Article last updated on: 25th June 2025.
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