Many people with epilepsy have focal seizures. Experts believe that up to 61% of people with epilepsy have them. 

The term ‘focal seizure’ covers a wide variety of symptoms. For example, one person’s focal seizure might make them taste or smell things that are not real, while another person’s focal seizures might make them blink or twitch.

So, what are the different types of focal seizures and why do they cause such different symptoms? 

If you have focal seizures, speak with your doctor about what they mean for you. This article is intended for general information, and is not medical advice.

What is a focal seizure?

A focal seizure is any kind of epileptic seizure that comes from just one part of the brain (a seizure is when the brain sends the wrong neuronal signals). 

Focal seizures are different from generalized seizures, where abnormal activity rapidly emerges on both sides of the brain (for more detail, read about the difference between generalized and focal seizures). 

Focal seizure symptoms can be very different depending on which part of the brain the seizure happens in.

Different types of focal seizures

People with focal seizures can have very different symptoms. The International League Against Epilepsy (ILAE) explains how they might be classified. It can be useful to know this, as doctors and epilepsy specialists may use these terms when talking about your epilepsy:

• Focal consciousness preserved seizure

This is when you have a seizure but remain aware of the world around you. 

• Focal consciousness impaired seizure

This means you lose awareness of the world around you when you have seizures. 

• Focal to bilateral tonic clonic seizure

This is when the seizure begins in one part of the brain, but the activity spreads to both hemispheres and leads to tonic-clonic seizures

Most focal seizures do not last very long - usually a few seconds, or up to a few minutes.

Focal seizure symptoms and location in your brain

Depending on where in your brain the seizure begins, you might experience very different focal seizure symptoms. 

• Frontal lobe: A focal seizure beginning in this part of the brain may cause motor features such as pelvic thrusting, kicking, pedalling or other movements. These seizures may also cause vocalizations, unusual behavior, urinary incontinence (losing control of the bladder) and head and eye deviations. 
• Occipital lobe: If the focal seizure happens in this part of the brain, you may have unusual sensory or visual experiences, eyelid fluttering, eye closure, eye deviation or eye movements.
• Parietal lobe: You may experience pins and needles, strange visual experiences or changes in perception. Language impairment may also occur, as well as rotatory body movements.
• Temporal lobe: Focal seizures beginning in this part of the brain can cause suddenly stopping what you were doing, repetitive movements or unusual feelings, strong emotions, hearing things and confusion.

There are many more possible symptoms - what is listed above is just intended to give an idea of the variety of experiences. Talk with your doctor about any sensations or behaviors you experience that may be related to your focal seizures.

Diagnosis and focal seizure treatment

If you believe you are experiencing focal seizures, talk to your doctor. To diagnose this kind of epilepsy, doctors may:

• Conduct a medical history to learn more about symptoms and other possible causes
• Use an EEG machine which can show unusual electrical activity in your brain and locate which part of the brain it’s happening in (EEG can only show electrical activity happening inside the brain at the time of the scan - so the scan may not show any epileptic activity, but this doesn’t rule out epilepsy)
• Use an MRI or CT scan which may help to discover if there is a specific cause of the seizures, such as a structural problem

If your doctor diagnoses you with epilepsy, they will work with you to create a strategy for your focal seizure treatment. The first line treatment for focal seizures is to take anti-seizure medication.

Learning about your focal seizures can help you understand your epilepsy and your experiences. Talk with your doctor about any concerns you may have or any questions about your personal situation.