Epilepsy is not a single medical condition in itself. It is a symptom of a range of other conditions that cause somebody to have repeated fits, known as seizures.
It is one of the more common neurological conditions, affecting 0.5-1 per cent of the population. Epilepsy is believed to affect around 456,000 people in the UK.
The cells in our brain (neurons) communicate with each other using electrical impulses. During a seizure these electrical impulses are abnormal and disrupted, which can cause both the brain and the body to behave strangely, commonly referred to as an epileptic attack.
The severity of the seizures can differ from person to person. Some people will just experience a trance-like state for a few seconds or minutes, whereas others will become unconscious and have convulsions, or uncontrollable shaking of the body. Other people may get abnormal sensations, such as tingling on one side of the body, or an awareness of a strange taste or smell. Some people also experience emotional symptoms such as fear or déjà vu.
Epilepsy attacks are usually brief, lasting from seconds to a few minutes. Once the attack is over, the normal electrical activity of the brain resumes.
Medication has proved remarkably successful for the majority of people with epilepsy. Once treatment begins, 70% of people will become seizure-free.
Doctors who treat epilepsy classify seizures by how much of the brain is affected. There are:
partial seizures - where only a small part of the brain is affected, and
generalised seizures - where most or all of the brain is affected.
There are two types of partial seizure:
simple partial seizure - a seizure where you remain conscious
complex partial seizure - a seizure where your consciousness is affected, you lose your sense of awareness and have no memory of the event.
There are six main types of generalised seizure, which are described below.
Absences: This type of seizure cause a loss of awareness of surroundings for five to 20 seconds.
Myoclonic jerks: These types of seizures cause your arms, legs or upper body to jerk or twitch, often only lasting for a fraction of a second.
Clonic seizure: This causes the same sort of twitching as myclonic jerks, except the symptoms will last longer, normally up to two minutes, and a loss of consciousness may occur.
Atonic seizure: Causes all of the muscles to suddenly relax, usually causing a fall to the ground.
Tonic seizure: Causes all of the muscles to suddenly become stiff, causing a loss of balance and a fall to the ground.
Tonic-clonic seizure: This type of seizure has two stages. The body becomes stiff and the arms and legs will begin twitching. The seizure which will involve loss of consciousness will normally lasts between one and three minutes. This is the most common type of seizure, accounting for 60% of all seizures experienced by people living with epilepsy. These are typically what people are referring to when using the term 'epileptic fit'.
You may also hear the terms Petit mal and Grand mal epilepsy. Both Petit mal epilepsy and Grand mal epilepsy are quite old-fashioned terms. Petit mal is now known as absence seizures, which neatly describes the momentary lapse in awareness that occurs during an episode. Grand mal epilepsy is the type of epilepsy that affects all or most of the brain at once, usually involving loss of consciousness.
Some people can identify the triggers of their seizures. Triggers can include:
lack of sleep
- alcohol or recreational drugs
- flashing or flickering lights such as strobe lighting (photosensitive epilepsy)
If the trigger of a seizure is known, it may be possible to find ways of avoiding the trigger to help to control the seizures.
Unforunately there is no cure for epilepsy, but epilepsy medicines can control seizures in around 7 out of 10 people.