How is epilepsy diagnosed and treated?

Diagnosing epilepsy can be difficult. Unless someone is having a seizure, there is often no obvious sign that they have epilepsy.

Many people will have a one-off seizure at some point in their lives, but a diagnosis of epilepsy is usually made after a person has had more than one seizure. 

The person who has the seizure may not remember what happened. So it can be very helpful to have a description of what happened, from someone who saw the seizure, to pass on to the specialist. 

A number of investigations may give more detailed information that can help with a diagnosis, including:

• blood tests;
• an electroencephalogram (EEG), a test where electrodes are used to record brain activity;
• a brain scan called Computerised Tomography (CT scan), which is a special type of x-ray using a scanner and a computer to take pictures of the brain; and
• Magnetic Resonance Imaging (MRI). This is a type of scan that uses strong magnetic fields and radio waves to produce detailed pictures of the brain.

However, these tests alone cannot confirm or rule out a diagnosis of epilepsy. Often it is a combination of test results, a person’s medical history, and information from those who saw the seizure, that is used to reach a diagnosis.

How is epilepsy treated?

Anti-seizure medication (ASM)

Up to 70% of people with epilepsy could have their seizures controlled (they stop having seizures), with the right medication. ASM is taken regularly to prevent seizures from happening, by reducing the brain’s excessive electrical activity. 

ASM is not used during a seizure to stop it, and it does not cure epilepsy. There are different ASMs, and the ASM that someone is prescribed depends partly on the type of seizures they have. 

Some people’s epilepsy goes into ‘spontaneous remission’ and they stop having seizures. When this happens they may be able to gradually stop taking their ASM, with guidance from their neurologist. 

Other people need to carry on taking ASM for the long term to keep their seizures under control. This may be the case if the underlying cause of the seizures is still there, for example a scar on the brain.

Other treatments for epilepsy

For some people whose epilepsy does not respond to ASM, other treatments may be possible:

• Epilepsy surgery (also called neurosurgery) may be possible for some people if tests are able to show where in the brain the seizures are starting.  
• VNS (Vagus nerve stimulation) therapy aims to help regulate the brain’s normal electrical activity to reduce the number or severity of seizures. It is a form of treatment that sends mild electrical stimulation to the brain through the vagus nerve (a large nerve in the neck). It is normally used alongside ASM.
• For some children and adults, the ketogenic diet may help to reduce the number or severity of their seizures. The diet is a medical treatment, often started alongside ASM, and is supervised by trained medical specialists and dietitians. Dietary treatments for adults are available on a limited basis in the UK.

Epilepsy Society is grateful to Dr F J Rugg-Gunn, Consultant Neurologist & Honorary Associate Professor, Clinical Lead, Chalfont Centre for Epilepsy, who reviewed this information.

Information updated: May 2024