Diagnosing epilepsy

Epilepsy is usually difficult to diagnose quickly. In most cases, it cannot be confirmed until you have had more than one seizure.

It can be difficult to diagnose because many other conditions, such as Migraine and panic attacks , can cause similar symptoms.

If you have had a seizure, you will be referred to a specialist in epilepsy, normally a neurologist (a doctor who specialises in conditions affecting the brain and nervous system).

Describing your seizures

Some of the most important pieces of information needed to diagnose epilepsy are the details about your seizure or seizures.

The doctor will ask you what you can remember and any symptoms you may have had before it happened, such as feeling strange before the seizure or experiencing any warning signs. It may be useful to talk to anyone who witnessed your seizure and ask them exactly what they saw, especially if you cannot remember the seizure.

The doctor will also ask about your medical and personal history and whether you use any medicines, drugs or alcohol.

The doctor may be able to make a diagnosis of epilepsy from the information you give, but they might run further tests such as an  electroencephalogram (EEG) or magnetic resonance imaging (MRI) scan .

However, even if these tests don't show anything, it is still possible that you have epilepsy.

Electroencephalogram (EEG)

An EEG test can detect unusual brain activity associated with epilepsy by measuring the electrical activity of your brain through electrodes placed on your scalp.

During the test, you may be asked to breathe deeply or close your eyes and you may be asked to look at a flashing light. The test will be stopped immediately if it looks like the flashing light could trigger a seizure.

In some cases, an EEG may be carried out while you are asleep (sleep EEG) or you may be given a small, portable EEG recording device to monitor your brain activity over 24 hours (ambulatory EEG).

Magnetic resonance imaging (MRI) scan

An MRI scan is a type of scan which uses strong magnetic fields and radio waves to produce detailed images of the inside of your body.

It can be useful in cases of suspected epilepsy because it can often detect possible causes of the condition, such as defects in the structure of your brain or the presence of a brain tumour. 

An MRI scanner is a large tube that contains powerful magnets. You lie inside the tube during the scan.

Want to know more?

• Epilepsy Society:  diagnosing epilepsy  
• Epilepsy Action: diagnosis