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Epilepsy and diagnosis FAQs
Answers to frequently asked question on epilepsy and diagnosis.
I don't have convulsions, so why does the neurologist say I have epilepsy?
There are lots of different types of epileptic seizures, almost 40 in fact. Not all seizures involve convulsions (jerking or shaking of the body). The seizure we often think of when we think about epilepsy is the convulsive, tonic clonic seizure, but not everyone has this type of seizure. So you might still have epilepsy even if the seizures you have don't involve convulsions. Because epileptic seizures happen in the brain and affect the way our brains work, any of the things that the brain controls can be affected such as our consciousness, movement and behaviour.
When diagnosing epilepsy, the neurologist usually looks at lots of different things, including your medical history and the circumstances when seizures occur, to see if there is any another reason for your seizures. They will also ask about what happens during your seizures. Adding all these things together is the basis of diagnosing epilepsy - or not.
I have seizures but I've been told it's not epilepsy. Why is this?
Not all seizures are caused by epilepsy. The word seizure describes any sudden, short event that causes a change in a person's awareness, their behaviour or feelings. So some seizures are caused by other conditions. For example, someone with diabetes could have a diabetic seizure; someone with a heart problem could have a seizure due to that condition; and some seizures happen for psychological reasons - these are often called non-epileptic seizures.
Epileptic seizures are seizures that are caused by a disruption in the way the brain normally works. Sometimes it can be confusing because when we refer to seizures on this website, we always mean epileptic seizure, but there are other types.
I have had seizures but my EEG and brain scan were both "normal". So why have I been diagnosed with epilepsy?
Epilepsy is a condition that is very difficult to diagnose. There is no single test that can say for certain that someone has epilepsy. The neurologist tries to get as much information from you to find out the most likely cause of your seizures. This includes looking at your medical history and asking you, and someone who saw your seizures, about what happened. It also often includes having an EEG and brain scan.
EEGs can sometimes be helpful in diagnosing epilepsy - if you have a seizure at the time of the EEG test. But EEGs can only show what is happening in your brain during the time you have the test. They cannot show what happened before the test, or what will happen afterwards. So if you don't have a seizure during the test, the EEG might not show any signs of epilepsy. Some people's brains show activity related to epilepsy in between seizures, and for them, the EEG might be helpful. A 'normal' or 'clear' EEG does not mean that someone does not have epilepsy.
Brain scans are used to see if there is any obvious physical or 'structural' reason in the brain for seizures to happen. For example some people have scar tissue, lesions or tumours that might cause their seizures. But for many people a brain scan will show nothing unusual. This doesn't mean that they haven't got epilepsy. It just means that there is no physical reason that can be seen in their brain to cause their seizures.
The neurologist said my EEG shows 'epileptiform activity'. What does this mean?
Epileptiform activity is the name given to the changes in brain activity, which are commonly seen in people who have epilepsy. EEGs can pick up the electrical activity of the brain through electrodes that are put on the head. If you have a seizure, it means that the electrical activity in your brain has been disturbed. If you have a seizure while having an EEG, this change in brain activity can be seen on your EEG.
Epileptiform activity can also be seen at times other than when seizures happen. This is called interictal epileptiform activity. If interictal epileptiform activity is seen, this does not prove a diagnosis of epilepsy, and if there's no interictal epileptiform activity, this doesn't rule epilepsy out.
The diagnosis of epilepsy is largely based on the history of the events that have happened. In people who are likely to have epilepsy, the EEG patterns are useful to determine the type of epilepsy.
How do I get a referral to a neurologist who specialises in epilepsy?
Many people with epilepsy are seen by a neurologist - a doctor who specialises in neurological conditions (conditions of the brain and nervous system). It is usually a neurologist who will diagnose your epilepsy, and discuss your treatment and management. In between seeing a neurologist, you would normally see your GP, for example for repeat prescriptions of your medication.
Sometimes people with epilepsy see a neurologist who specialises in epilepsy. If you want to be referred to an epilepsy specialist, you would need a medical referral. This is a referral from either your GP or your usual neurologist. You wouldn't be able to refer yourself, but you can ask your GP or neurologist if they will do this for you.
© Epilepsy Society
Information updated in November 2012.