Getting a diagnosis

• Introduction
• The tests
• Questions you may be asked
  
  

Introduction

If you think you might have had an epileptic seizure you should first consult your family doctor. If your family doctor thinks that you may have had a seizure, they should refer you to an epilepsy specialist, usually a neurologist. In some areas of the UK there are dedicated epilepsy clinics that offer extra services in addition to consultants with expertise in epilepsy. These can include a counsellor or an epilepsy specialist nurse.

The diagnosis of epilepsy is mainly based on the description of the seizure given by the person themselves and any eye witness accounts. There are also hospital tests that can help the doctor in their diagnosis, although not everyone will necessarily be required to have every test. At the moment, there is no single test available that can say if someone does or does not have epilepsy.

The tests

EEG (electroencephalogram)

The EEG is a painless investigation that tells doctors about the activity of the brain. During an EEG, electrodes are placed on the scalp using a special glue or sticky tape. These electrodes are connected to the EEG machine that records - on paper or computer - the electrical signals from the brain.

During the test you are asked to do things such as open and close your eyes, breathe deeply and look at flashing lights. If your seizures appear to be connected to your sleep pattern, it may be decided to record an EEG during sleep or after a time of being deprived of sleep.

It is important to remember that an EEG only shows what is happening in the brain at the time it is being carried out. It cannot show what happened yesterday or predict what is going to happen tomorrow. An abnormal EEG does not necessarily mean that someone has epilepsy and a normal EEG does not necessarily mean that someone does not have epilepsy. However, it is a common test in investigating epilepsy and can be very helpful to doctors.

• More detailed information on the EEG

CT (computerised tomography)

This scan is a type of X-ray that looks at the structure of the brain. It does not show if someone has epilepsy but it may show if there is an abnormality that could cause epilepsy. It will not be appropriate or necessary for everyone to have a CT scan.

MRI (magnetic resonance imaging)

Like the CT scan, the MRI can show if there is a structural cause for a person’s epilepsy. However, the MRI is a more powerful machine, so it may pick up abnormalities that the CT scanner may not detect. The MRI uses radio waves and a magnetic field, rather than X-rays.

• More detailed information on MRI

Other scans

Other scans that are sometimes used are PET (Positron Emission Tomography) and SPECT (Single Photon Emission Computerised Tomography). In both of these a fluid is injected into the bloodstream that produces a picture of the blood flow. These investigations are mainly used when epilepsy surgery is being considered and, even then, only in a very small number of cases.

DTI (diffusion tensor imaging)

The DTI scanner, which measures the movement of water in the brain to detect underlying abnormalities, has been found to pick up abnormalities in some cases where an MRI has failed to do so. There are only a few DTI scanners in the UK, and this investigative technique is still being developed.

• More information about DTI

Blood tests

These check your general health and look for other possible causes of the seizure, such as an underlying disease or condition.

Questions you may be asked

The doctor will ask questions to help with their diagnosis. Here are some examples of questions they may ask you.

• How did you feel before you had the seizure, for example hot, cold, hungry, tired etc?
• Did you experience any unusual symptoms beforehand, for example nausea, dizziness, chest pain?
• Had you drunk any alcohol or taken any drugs of any kind?
• Did you have any warning beforehand? If so, what?
• Do you remember anything about the seizure? If not, what happened when you came round?
• Did you fall over and/or injure yourself?
• Were there any symptoms after the seizure?
• How many seizures have you had?
• Are there any other factors which could suggest epilepsy, for example, head injury, previous seizures, other people in your family with epilepsy?

If someone witnessed your seizure and they can come with you to the appointment, the doctor may also ask them some questions.

• What were they doing when the seizure started?
• What exactly happened when they had the seizure?
• How long did the seizure last?
• Did they appear confused after the seizure?

See also

• Keeping a seizure diary
• Visiting your doctor

Further information on this is available from Epilepsy Action by using the Email Helpline or if you live in the UK, by phoning the Freephone Helpline on 0808 800 5050.

11 July 2006