When an epileptic seizure starts in one side of the brain, it’s called a focal onset seizure or a focal seizure. Both terms mean the same thing. Until recently these seizures were called partial seizures.
What are the different types of focal seizure?
There are many different types of focal seizure, but they can be split into two main types according to what level of awareness you have during the seizure.
Focal aware seizures
During a focal aware seizure, you stay fully aware of what’s happening around you, even if you can’t move or respond. This type of seizure used to be called a simple partial seizure.
What are auras?
Some people with epilepsy use the word ‘aura’ to describe the feeling they get that warns them they’re about to have a tonic-clonic seizure. The aura is in fact the seizure starting in one side of the brain as a focal aware seizure. The seizure then spreads to affect both sides of the brain. See focal to bilateral tonic-clonic seizures.
Focal aware seizures can also happen on their own, without developing into another seizure type. Some people who have focal aware seizures on their own also call them auras.
Focal impaired awareness seizures
If your awareness of what’s happening around you is affected at any time during your seizure, it’s called a focal impaired awareness seizure. This type of seizure used to be called a complex partial seizure.
Motor or non-motor
Doctors may also use the words motor or non-motor to describe focal seizures. Focal motor describes focal seizures where the main symptoms involve muscle activity, such as jerking, loss of muscle tone or repeated movements. Focal non-motor describes seizures where the main symptoms don’t involve muscle activity. They can include things like changes in emotions, thinking and sensations.
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What happens during a focal seizure?
What happens during a focal seizure depends on which area (lobe) of the brain is affected, and whether the seizure spreads to affect other areas. Some people just experience one symptom during a focal seizure, while others experience several.
The symptoms of frontal lobe seizures can sometimes be mistaken for mental health problems or sleep disorders. Some people who have frontal lobe seizures only have them in their sleep. They are usually brief, but often happen in clusters, with several happening in a short space of time. Your awareness may or may not be affected.
Symptoms of seizures in the frontal lobes can include:
- Pelvic thrusting, kicking, pedalling, thrashing or rocking movements
- Screaming, swearing or laughing
- Unintentionally passing urine (urinary incontinence)
- Your head or eyes turning to one side
- Having unusual body movements, such as stretching one arm while the other bends
- Twitching, jerking or stiffening of muscles in one area of your body. The movements may sometimes spread bit by bit to other areas
Seizures starting in the occipital lobe often spread to involve other lobes.
Symptoms of seizures starting in the occipital lobe include:
- Seeing flashing lights, colours or simple patterns
- Seeing more complex images, such as pictures of people, animals or scenes
- Not being able to see as well as usual, or not being able to see at all
- Having eye movements you can’t control, such as your eyes closing, moving to one side or rapidly moving from side-to-side
- Eyelid fluttering
Seizures starting in the parietal lobe often spread to involve other lobes.
Symptoms of seizures starting in the parietal lobes can include:
- Having feelings of numbness or tingling
- Prickling, crawling or electric-shock sensations, which may spread along the affected body part
- Sensations of burning, cold or pain
- Feeling like part or all of your body is moving or floating
- Feeling like a body part has shrunk, enlarged or is missing
- Sexual sensations
- Difficulty understanding language, reading, writing or doing simple maths
- Seeing things as larger or smaller than they really are, or seeing things that aren’t there
If you have been diagnosed with temporal lobe epilepsy (TLE) it means you have seizures starting in one or other of the temporal lobes. Seizures starting in the temporal lobes are usually focal impaired awareness seizures, but focal aware seizures can also happen. You might start the seizure being aware of what’s happening, and then lose awareness as the seizure progresses.
Symptoms of seizures in the temporal lobes include:
- Feeling frightened
- Feeling like what’s happening has happened before (deja vu)
- Hearing things that aren’t there
- Experiencing an unpleasant taste or smell
- Having a rising sensation in your stomach
- Lip smacking, repeated swallowing or chewing
- Changes to your skin tone or heart rate
- Automatic behaviours such as fidgeting, undressing, running or walking
After a temporal lobe seizure you are likely to be confused, and may find it hard to speak for a short time.
How long do focal seizures last?
Most focal aware seizures are brief, lasting between a few seconds and 2 minutes. Focal impaired awareness seizures usually last between one and 2 minutes.
What happens after a focal seizure?
What happens after a focal seizure varies from person to person. You might feel fine after a focal seizure and be able to get back to what you were doing straight away. Or you might feel confused or tired for some time afterwards. You might need to sleep.
Some people find they have temporary weakness or can’t move part of their body after they’ve had a seizure. This is called Todd’s paresis or Todd’s paralysis. It can last from a few minutes up to 36 hours, before going away.
How can someone help me during a focal seizure?
You might not need any help from people around you during a focal seizure, especially if it’s brief and you’re aware of what’s happening. But if you’re not aware of what you’re doing you might need help to guide you away from danger and keep you safe. See our first aid information, or ask them to take our short online course which shows them what to do when someone has a seizure.
See this information with references
If you would like to see this information with references, visit the Advice and Information references section of our website. If you are unable to access the internet, please contact our Epilepsy Action Helpline freephone on 0808 800 5050.
Epilepsy Action would like to thank Dr John Paul Leach, consultant neurologist at the Queen Elizabeth University Hospital, Glasgow, for this contribution to this information.
Dr Leach has declared no conflict of interest.
This information has been produced under the terms of Epilepsy Action's information quality standards.
- Updated November 2019To be reviewed July 2022