Epileptic seizures are caused by a disturbance in the electrical activity of the brain. There are many different types of epileptic seizure. Any of us could potentially have a single epileptic seizure at some point in our lives. This is not the same as having epilepsy, which is a tendency to have seizures that start in the brain. Here we cover the different types of epileptic seizure and what they can look like.
Whether you, or someone you know, has had a single seizure or has been diagnosed with epilepsy, it may help to identify the type of seizures that are relevant to you, and how you feel about them.
Are all seizures the same?
Some seizures are caused by conditions such as low blood sugar (hypoglycaemia) or a change to the way the heart is working. Some very young children have 'febrile convulsions' (jerking movements) when they have a high temperature. These are not the same as epileptic seizures.
On this page when we use the word ‘seizure’ we mean epileptic seizure.
The brain and epileptic seizures
The brain has millions of nerve cells (or neurones) which control the way we think, move and feel. The nerve cells do this by passing electrical signals to each other. If these signals are disrupted, or too many signals are sent at once, this causes a seizure (sometimes called a ‘fit’ or ‘attack’).
The brain has many different functions. Our moods, memory, movement, consciousness and our senses are all controlled by the brain and any of these can be affected if someone has a seizure. They may feel strange or confused, behave in an unusual way, or lose some or all awareness during the seizure.
How epilepsy is described
You may see epilepsy described in two ways. One way describes the type of epilepsy, the other describes the type of seizure.
The type of epilepsy depends on the cause of the epilepsy. For example, 'symptomatic epilepsy' means there is a known cause (such as a brain injury) and 'idiopathic epilepsy' means that the epilepsy is usually genetic or inherited.
The type of seizure depends on what happens to the person during the seizure. Here, we look at the types of seizures and not the types of epilepsy.
Some facts about seizures
- Most seizures happen suddenly without warning, last a short time (a few seconds or minutes) and stop by themselves.
- Seizures can be different for each person.
- Just knowing that someone has epilepsy does not tell you what their epilepsy is like, or what seizures they have.
- Calling seizures ‘major’ or ‘minor’ does not tell you what happens to the person during the seizure. The names of seizures used on this page describe what happens during the seizure.
- Some people have more than one type of seizure, or their seizures may not fit clearly into the types described on this page. But even if someone's seizures are unique, they may follow the same pattern for that person.
- Not all seizures involve convulsions (jerking or shaking movements). Some people appear vacant, wander around or seem confused during a seizure.
- Some people have seizures when they are awake, called 'awake seizures'. Some people have seizures while they are asleep, called 'asleep seizures' (or ‘nocturnal seizures’). The names 'awake' and 'asleep' do not explain the type of seizures, only when they happen.
- Injuries can happen during seizures, but many people don't hurt themselves and don't need to go to hospital or see a doctor. See first aid for all seizure types
Types of seizures
Seizures are divided into two main types: focal seizures (also called partial seizures) and generalised seizures. Epileptic seizures always start in the brain.
The brain has two sides called hemispheres. Each hemisphere has four parts called lobes. Each lobe is responsible for different things such as vision, speech and emotions.
Focal (partial) seizures
In focal seizures the seizure starts in, and affects, just part of the brain. This is sometimes called the 'focus' of the seizures. It might affect a large part of one hemisphere or just a small area in one of the lobes.
What happens during the seizure depends on where in the brain the seizure happens and what that part of the brain normally does.
Simple focal seizures
In simple focal seizures (SFS) a small part of one of the lobes of the brain is affected. The person is conscious (aware and alert) and will usually know that something is happening and will remember the seizure afterwards.
Some people find their simple focal seizures (SFS) hard to put into words. During the seizure they may feel ‘strange’ but not able to describe the feeling. This may be upsetting or frustrating for them.
SFS are sometimes called ‘warnings’ or ‘auras’ because, for some people, a SFS develops into another type of seizure. Then the SFS is a warning that another seizure will happen (see secondarily generalised seizures below).
Temporal lobe simple focal seizures may include:
- a ‘rising’ feeling in the stomach (like the feeling you get on a fairground ride where you 'leave your tummy at the top')
- deja vu (feeling like you've 'been here before') or jamais vu (where familiar things seem new)
- getting an unusual smell or taste
- a sudden intense feeling of fear or joy.
Frontal lobe simple focal seizures may include:
- strange movements
- a strange feeling like a ‘wave’ going through the head
- stiffness or twitching in part of the body (such as an arm or hand). This might start in one place, for example the face, and spread to other parts of the body.
Parietal lobe simple focal seizures may include:
- a feeling of numbness or tingling
- burning sensations or a feeling of heat
- a sensation that an arm or leg feels bigger or smaller than it actually is.
Occipital lobe simple focal seizures may include:
- distorted or loss of vision
- visual disturbances such as coloured or flashing lights
- hallucinations (seeing something that isn’t actually there).
Complex focal seizures
Complex focal seizures (CFS) affect a bigger part of one hemisphere (side) of the brain than a simple focal seizure. The person’s consciousness is affected and they may be confused. They might make strange or repetitive movements that have no purpose (called ‘automatisms’). They may wander around, or behave strangely, and they may not be aware of what they are doing.
They might be able to hear you, but might not fully understand what you say or be able to respond to you. They may not react to you they would normally. If you speak loudly to them, they may think that you are being aggressive and so they may react aggressively towards you.
CFS often happen in the temporal lobes ('temporal lobe epilepsy') but can happen in other parts of the brain.
Temporal lobe complex focal seizures may include:
- picking up objects for no reason or fiddling with clothing
- chewing or lip- smacking movements
- muttering or repeating words that don't make sense
- wandering around in a confused way.
These CFS may start with a simple focal seizure and last around two or three minutes (about the length of a song on the radio). It can then take the person around 5 - 10 minutes to come around.
Frontal lobe complex focal seizures may include:
- making a loud cry or scream
- making strange postures or movements such as cycling or kicking.
These CFS usually last around 15 - 30 seconds (about the length of a TV advert). Afterwards the person will usually recover quite quickly.
Complex focal seizures in the parietal or occipital lobes are less common than in the temporal or frontal lobes. Like the simple focal seizures, CFS in the parietal and occipital lobes can affect the person’s senses or vision. These CFS usually last around 15 - 30 seconds.
After a complex focal seizure, the person may be confused for a while, sometimes called 'post-ictal' (after seizure) confusion. It may be hard to tell when the seizure has ended. The person might be tired and want to rest. They may not remember the seizure afterwards.
Secondarily generalised seizures
Sometimes focal seizures spread from one side (hemisphere) to both sides of the brain. This is called a secondarily generalised seizure because it starts as a focal seizure and then becomes generalised. When this happens the person becomes unconscious and will usually have a tonic clonic (convulsive or shaking) seizure. If this happens very quickly, they may not be aware that it started as a focal seizure.
Generalised seizures affect both sides of the brain at once and can happen without warning. The person will be unconscious (except in myoclonic seizures), even if just for a few seconds. Afterwards they will not remember what happened during the seizure.
Absences (sometimes called petit mal)
Absence seizures are more common in children than adults and can happen very frequently. During an absence a person becomes unconscious for a short time. They may look blank and stare, or their eyelids might flutter. They will not respond to what is happening around them. If they are walking they may carry on walking but will not be aware of what they are doing.
Absences can be confused with daydreaming. However, unlike daydreaming, someone who is having an absence will not usually respond. Also, if blank spells happen when someone is doing something that they enjoy, such as talking or playing a game, then this is less likely to be daydreaming.
In typical absences, the person becomes blank and unresponsive for a few seconds. Because the seizures are so brief, they may not be noticed.
Atypical absences often last a bit longer than typical absences. They often have some physical movement with them such as a brief head nod or jerking of the shoulders. Atypical absences may happen to people with learning disabilities who may have other types of seizures as well.
In a tonic seizure the person’s muscles suddenly become stiff. If they are standing they often fall, usually backwards, and may injure the back of their head. Tonic seizures tend to be very brief and happen without warning.
In an atonic seizure (or 'drop attack') the person’s muscles suddenly relax and they become floppy. If they are standing they often fall, usually forwards, and may injure the front of their head or face.
With both tonic and atonic seizures people usually recover quickly, apart from possible injuries.
Myoclonic means ‘muscle jerk’. Muscle jerks are not always due to epilepsy (for example, some people have them as they fall asleep).
Myoclonic seizures are brief but can happen in clusters (many happening close together in time) and often happen shortly after waking. They usually involve jerking of the arms or legs but can also affect the head or trunk (top half of the body).
In myoclonic seizures the person is conscious. They are classified as generalised seizures because the person is likely to have other seizures (such as tonic clonic seizures) as well as myoclonic seizures.
Tonic clonic (convulsive) seizures (sometimes called grand mal)
These are the seizures most people think of as epilepsy.
At the start of the seizure:
- the person becomes unconscious
- their body goes stiff and if they are standing up they usually fall backwards
- they may cry out
- they may bite their tongue or cheek.
During the seizure:
- they jerk and shake (convulse) as their muscles relax and tighten rhythmically
- their breathing might be affected and become difficult or sound noisy
- their skin may change colour and become very pale or bluish
- they may wet themselves.
After the seizure (once the jerking stops):
- their breathing and colour return to normal
- they may feel tired, confused, have a headache or want to sleep.
Clonic seizures are convulsive seizures but the person's body does not go stiff at the start.
An individual's seizures usually last the same length of time each time they happen and stop by themselves. However, sometimes seizures do not stop or one seizure follows another without the person recovering in between. If this goes on for 30 minutes or more it is called status epilepticus or ‘status’.
Status is not common but it can happen in any type of seizure and the person may need to see a doctor. However, status in a tonic clonic (convulsive) seizure is a medical emergency and the person will need urgent medical help. Call for an ambulance if a tonic clonic seizure lasts for more than five minutes,
Some people’s seizures are brought on or ‘triggered’ by certain situations. Triggers can differ from person to person and include lack of sleep, stress, alcohol and flickering lights (called photosensitive epilepsy). Knowing what triggers someone’s seizures means that they might be able to avoid these situations.
Some people with epilepsy make a note of when their seizures happen in a seizure diary. This means they can see if their seizures change in length or frequency over time. If their seizures do change, it might be helpful for them to have their epilepsy reviewed by their doctor.
Our free smartphone app contains seizure management tools, including a seizure diary to help you monitor your triggers. It is available on both iPhone and Android phones. Download it now. Alternatively download a PDF seizure diary or get a printed seizure diary from our shop.
Training and resources
- Order a copy of our 'seizures' leaflet from our online shop as part of our 'first five free' offer.
- Order our 'Epileptic Seizures' DVD which contains footage of real seizures and information about first aid. It is ideal for training purposes.
Training is available from Epilepsy Society on epilepsy awareness, including management of seizures.
switchboard 01494 601 300