Healthdirect Free Australian health advice you can count on.

Medical problem? Call 1800 022 222. If you need urgent medical help, call triple zero immediately

healthdirect Australia is a free service where you can talk to a nurse or doctor who can help you know what to do.

EEG is a test that measures the electrical activity of your brain by using electrodes attached to your head.

EEG is a test that measures the electrical activity of your brain by using electrodes attached to your head.
beginning of content

Electroencephalogram (EEG)

An electroencephalogram, or EEG, is a test that measures the electrical activity of the brain. It can be used to diagnose or monitor conditions that affect the brain, such as epilepsy and sleep disorders. Your doctor will let you know if you need to have an EEG.

What is an EEG test?

An EEG records the electrical signals sent between brain cells.

This electrical activity is shown on a computer as ‘brain waves’, which are interpreted by a specialist doctor.

If something is unusual about the brain’s electrical activity, it will show up in the EEG recording.

The test is safe and doesn’t hurt.

What conditions can an EEG test help diagnose?

Your doctor may recommend an EEG to diagnose or monitor:

An EEG cannot diagnose mental illnesses. And while an EEG is one of the main tools for diagnosing epilepsy, a negative or normal EEG test does not necessarily rule epilepsy out.

What does an EEG test involve?

During the EEG, flat metal discs (electrodes) will be placed all over your scalp. They are usually kept in place with a sticky paste. You won’t need to cut your hair.

These discs are also attached to wires that send the electrical signals to a computer to record the brain waves. You won’t feel any sensations from the discs.

As part of the test you will need to keep still. You may be asked to do some deep breathing, look at a flashing light or sleep during the test.

An EEG takes about an hour, but may be longer for a sleep recording.

How to prepare for an EEG test

Wash your hair the night before or the day of the test, so that the discs stay attached to your scalp. Avoid using conditioners, hairsprays, styling gels or other hair products.

It’s also best to avoid food or drinks that contain caffeine (including coffee, tea, cola and chocolate) for at least 8 hours before the test.

Your doctor will let you know if you need to stop taking any of your medicines beforehand.

Last reviewed: February 2016

Need more information?

These trusted information partners have more on this topic.

Found 11 results

EEG test - Better Health Channel

In a person with epilepsy, an electroencephalogram (EEG) may show bursts of abnormal discharges in the form of spikes and sharp wave patterns.

Read more on Better Health Channel website

Epilepsy in children

With treatment, most children with epilepsy lead a fairly normal life. Learn about causes, what to do during seizures and how to help avoid epileptic fits.

Read more on Pregnancy, Birth & Baby website

Diagnosis | Epilepsy Action Australia

Epilepsy Diagnosis - As part of diagnosis, the doctor will do routine physical and neurological examinations which may include blood tests.

Read more on Epilepsy Action Australia website

Creutzfeldt-Jakob disease and variant Creutzfeldt-Jakob disease - including symptoms, treatment and prevention :: SA Health

These are progressive fatal infections of the brain caused by an infectious protein particle called a prion. These diseases are some of a group of brain infections known as Transmissible Spongiform Encephalopathies (TSE).

Read more on SA Health website

Epilepsy -

Epilepsy is a condition in which the electrical and chemical activity of the brain loses its usual co-ordination for short periods of time, resulting in seizures (also called fits or convulsions).

Read more on myDr website

Seizures and Epilepsy | The Sydney Children's Hospitals Network

Read more on Sydney Children's Hospitals Network website

Seizures in children

Seeing your child have a seizure or convulsion can be frightening. Learn what to do, how seizures are diagnosed and treated, and how to help prevent fits.

Read more on Pregnancy, Birth & Baby website

Fronto temporal lobar degeneration -

What are the differences between Pick`s disease and fronto temporal lobar degeneration or dementia? Find out about symptoms, prognosis and treatment.

Read more on myDr website

Childhood trauma and abuse affect brain physiology

Blue Knot Foundation discusses the neurological impact of childhood trauma and abuse on cortex, limbic system, left/right brain hemispheres, stress hormones.

Read more on Blue Knot Foundation website

Creutzfeldt-Jakob disease -

Creutzfeldt–Jakob disease (CJD) is a fatal, degenerative brain disorder that causes rapidly progressive dementia and loss of muscle control. It is a rare disease, affecting 1–2 people in every million in Australia.

Read more on myDr website

Check your symptoms Find a health service

Healthdirect 24hr 7 days a week hotline

24 hour health advice and information you can count on

1800 022 222

Government Accredited with over 140 information partners

We are a government-funded service, providing quality, approved health information

Australian Government, health department logo ACT Government logo New South Wales government, health department logo Northen Territory Government logo Government of South Australia, health department logo Tasmanian government logo Government of Western Australia, health department logo