St Valentine Patron Saint of Epilepsy. Did you know this?

15. Feb, 2017

Focal seizures

Seizure classification
Focal seizures

Todd’s paresis (sometimes called Todd’s paralysis)
Focal seizures that act as a warning of a generalised seizure

Seizure classification

The International League Against Epilepsy (ILAE), a world-wide organisation of epilepsy professionals, has put together a list of the names of different seizure types. This is called the ILAE seizure classification. The names and information given about different types of seizures in this booklet are based on this classification. The ILAE regularly looks at seizure classifications, so the names may change over time.

Some people use different words to describe seizures. But it is important for doctors to give seizures the right names. This is because specific medicines and treatments can help some seizure types but not others.

Seizure types

There are many different types of seizure. They can happen in any part of the brain. Some seizures are generalised, meaning they affect both halves of the brain. Others are focal, meaning they affect a small part of the brain. The brain is responsible for all the functions of our mind and body. What happens to someone during a seizure will depend on where in their brain the seizure is happening.

Focal (partial) seizures

In focal seizures, epileptic activity starts in just part of the person’s brain. You might be aware of what is going on around you in a focal seizure, or you might not. Different areas of the brain (lobes) are responsible for controlling all of our movements, body functions, feelings or reactions. So, focal seizures can cause many different symptoms.  

The structure of the brain

3D image showining different parts of the brain

 

Seizures can start in any of these lobes. What happens during a seizure will be different, depending on which lobe, and which part of the lobe, the seizure starts in. Each person will have their own experiences and symptoms during a focal seizure.

Temporal lobes

The temporal lobes are responsible for many functions, including hearing, speech, memory, emotions, and learning.

People who have temporal lobe seizures may stay partially conscious during a seizure. Or they may lose consciousness. They often don’t remember what happened to them during a seizure.

Temporal lobe seizures usually last between 30 seconds and two minutes. Some of the signs and symptoms of temporal lobe seizures include:

  • Feeling frightened
  • Having a deja-vu experience, that is a feeling that what’s happening has happened before
  • Having a strange taste, or smelling something that isn’t there
  • Having a rising sensation in the stomach
  • Staring
  • Lip smacking
  • Automatic behaviours such as staring, lip smacking, repeated swallowing, chewing or more complex tasks, such as dressing or undressing.

After a temporal lobe seizure, you might be confused and find it difficult to speak for a short time.

Frontal lobes

The frontal lobes are responsible for making decisions, solving problems, behaviour, consciousness, and emotions. If you have frontal lobe seizures, you may have unusual symptoms that can be mistaken for a mental health problem or a sleep disorder. Frontal lobe seizures usually last less than 30 seconds and often happen during sleep.

Signs and symptoms of frontal lobe seizures may include:

  • Moving your head or eyes to one side
  • Not being aware of your surroundings, or having difficulty speaking
  • Screaming, swearing or laughing
  • Having unusual body movements, such as stretching one arm, while bending the  other, as if you were posing like a fencer
  • Having repeated movements, such as rocking, pedalling or pelvic thrusting

Parietal lobes

Parietal lobes are involved with:

  • Processing information from the different senses in the body (seeing, hearing, touching, tasting and smelling)
  • Processing language
  • Writing
  • Maths skills

Parietal lobe seizures last between a few seconds and a few minutes. They affect about one in 20 people with epilepsy. 

Signs and symptoms of parietal lobe seizures may include:

  • Having feelings of numbness, tingling, heat, pressure, electricity and, rarely, pain
  • Having a ‘marching’ sensation that starts in your face, goes to your hand, then your arm, and down your leg (this is called a Jacksonian seizure)
  • Having sexual sensations
  • Feeling like your body is distorted, and that your arms or legs are in a weird position or are moving, when they are not
  • Feeling that a part of your body is missing or doesn’t belong to you
  • Feeling dizzy or as if you, or the area around you, is spinning
  • Seeing things that are not there, or seeing things differently from how they really are. For example objects might seem too close, too far away, too large, too small, slanted, moving or otherwise not right
  • Having difficulty understanding spoken words or language, difficulty reading or doing simple maths

Occipital lobes

The occipital lobes process information related to vision. They affect between one in five and one in 10 people with epilepsy.  They last for seconds.

Some of the signs and symptoms of occipital lobe seizures are:

  • Seeing things that are not there
  • Not seeing as well as usual, or not being able to see at all
  • Seeing an image that is replayed again and again
  • Feeling as if your eyes are moving
  • Having eye pain
  • Having sideways eye movements that you can’t control
  • Having rapid rhythmic eye movements where your eyes move quickly in one direction, and then slow down in the other direction. This is called nystagmus
  • Having fluttering eyelids

Todd’s paresis (sometimes called Todd’s paralysis)

Todd's paresis is a temporary weakness or paralysis in a hand, arm or leg. It affects some people after they have had a focal or generalised seizure.

Todd’s paresis affects the area of the body that was involved in the seizure. The weakness can be very mild, or it can completely paralyse that part of the body, or affect vision. Todd’s paresis usually occurs in just one side of the body. It can last from minutes to hours, before going away.

Focal seizures that act as a warning of a generalised seizure

The epileptic activity that causes a focal seizure can sometimes spread through the brain and develop into a generalised seizure. If this happens, the focal seizure acts as a warning of a generalised seizure and is sometimes called an aura. The aura is usually brief, lasting a few seconds or so, although in rare cases, auras can last for minutes, hours, or even days. Once the epileptic activity spreads to both halves of your brain, you quickly have a generalised seizure, usually a tonic-clonic, tonic or atonic seizure.

Warnings can be very useful. They might give you time to get to safe place or let someone else know that you are going to have a seizure. Sometimes, the epileptic activity spreads to both halves of your brain so quickly that you appear to go straight into a generalised seizure.