Focal seizures are a type of seizure that affects only one side of your brain and body. These seizures tend to be less severe than generalized seizures, which affect both sides of your brain and body. Focal seizures are the most common type of seizures with epilepsy, and are often seen with conditions like stroke, head injuries and more.
Focal seizures — formerly known as partial seizures — are seizures that happen in specific parts of your brain. Focal seizure symptoms reflect the region of brain from which they originate.
The initial symptoms of focal seizures may involve odd experiences during which time awareness is maintained. However, if the seizures continue to spread to other regions of your brain, they can sometimes progress to a loss of awareness (tonic-clonic seizures).
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A seizure is an uncontrolled surge of electrical activity in your brain. That surge causes affected brain cells (neurons) to send signals to other neurons around them. The symptoms of seizures depend on where they happen in your brain.
Your brain has left and right halves, known as hemispheres. Generalized seizures affect both hemispheres of your brain, causing symptoms that affect both sides of your body. These are usually more severe.
Focal seizures begin in one location within your brain — in either the right or left hemisphere. As the seizure intensifies, the surge of electrical activity can move from one location to another and eventually even cross from one brain hemisphere to another. In some instances, a focal seizure can progress to a “generalized tonic-clonic seizure.” Today, healthcare providers call these seizures “focal to bilateral tonic-clonic seizures”.
NOTE: Seizures and epilepsy aren’t the same thing, either. For more general information, including the difference between seizures and epilepsy, see our main seizure article.
Anyone can have seizures under the right circumstances. However, focal seizures can happen more easily if you have certain brain conditions. Focal seizures are most common in people who have head injuries, birth abnormalities of their brain, febrile seizures in childhood, infections of their brain (encephalitis), strokes, brain tumors or other conditions that affect their brain.
Focal seizures are the most common type of seizure, making up more than half of all seizures. One specific type of seizure, focal (impaired awareness), makes up just over one-third of all seizures.
The symptoms that occur during a focal seizure depend on where in your brain the seizure happens. Symptoms that can arise from a focal seizure are described below. It is important to control focal seizures because over time they can lead to memory problems or issues with thinking ability. They can also increase your risk for some mood disorders like depression and anxiety.
Some people with focal seizures can experience an aura. Auras can be the initial symptoms of a focal seizure. Auras occur while you're still aware, and during this time you can experience a wide variety of symptoms. When focal seizures don’t spread, an aura can be the only manifestation of the seizure.
Auras can take many different forms. These include:
Auras don’t happen in people with generalized epilepsy. Their presence suggests a diagnosis of focal epilepsy. When an aura from a focal seizure happens, it can sometimes be a warning sign for people, as auras can evolve into a seizure with a loss of awareness.
Focal seizure symptoms depend on the type of seizure and its location in your brain. There are three main kinds of focal seizures:
Focal seizure symptoms fall into four different groups, and a seizure can involve more than one of these groups. The groups are:
Seizures with motor effects cause unconscious or involuntary movements. These often affect your face, hands and toes on one side. They can involve twitching or jerking muscle movements, uncontrolled tightening up of muscles, or repetitive/automatic movements (smacking your lips, blinking or tapping a hand or finger).
Focal motor symptoms can also spread across an affected body part and to other parts of your body. The name for this effect is “Jacksonian march.” These seizures start in a small area and then "march" to the entire body part, and often continue onto other body parts or the face on the same side.
After focal motor symptoms happen, many people have paralysis in their affected body parts. Known as “Todd paralysis,” this is a temporary effect, but it can last several hours. Telling your healthcare provider about this can help with diagnosing and treating seizures.
If an aura affects neurons in parts of your brain connected to your senses, the neurons can mistakenly act like they’re getting real input. That can make you think something is happening when it really isn’t. These kinds of symptoms, known as hallucinations, can affect all five of your senses. Examples include:
It’s important to describe any sensory symptoms and hallucinations to your provider as best you can. Knowing about the affected sense(s) can help providers locate where a seizure happened in your brain.
Auras can affect body systems that your brain runs automatically. Some examples include:
Auras cause changes in your emotional state. Examples of this include:
Other cognitive changes that occur in focal seizures include changes in level of awareness, changes to memory, changes to your language function or ability to communicate and impairment to interact with your environment appropriately.
Focal seizures can happen for many reasons, including the following:
No, focal seizures aren't contagious. However, some conditions that cause focal seizures are genetic (you can inherit them from your parents, or your children can inherit them from you).
A healthcare provider, usually a neurologist, can diagnose focal seizures based on the symptoms you had (or that others describe) and diagnostic tests. These tests can usually confirm if you had a seizure and whether it was provoked or unprovoked. Genetic tests can also uncover inherited conditions that cause seizures.
A key part of diagnosing focal seizures is finding the focal point, a specific area where the seizure(s) started. Locating the focal point can greatly help with treating focal seizures.
Possible tests with seizures include:
Providers might also recommend other tests to determine if you have any kind of injury, side effects or complications from a seizure. Your healthcare provider is the best person to tell you (or someone you choose to make medical decisions for you) what kind of tests they recommend and why.
Diagnosing and treating focal seizures starts with finding out if they're provoked or unprovoked. When possible, treating the underlying cause of provoked seizures can often stop seizures from happening. If the underlying cause isn't treatable, healthcare providers will usually try to treat the seizures, so they are less severe or happen less often.
Providers usually recommend against treating first-time unprovoked seizures unless you have a high risk of having another. If you have a high risk or have had an unprovoked seizure before, they'll likely diagnose you with epilepsy and recommend starting treatment.
The treatments for focal seizures vary widely. For provoked seizures, the treatments almost always depend on the cause. The treatments for unprovoked and epilepsy-related seizures depend on the type(s) of seizures, why they are happening and which treatments work best.
Possible treatments for seizures due to epilepsy include:
The possible complications with seizure treatments depend on the cause, type of seizure and more. Your healthcare provider is the best person to tell you what you can or should expect. That's because they can give you relevant information about your specific case.
You shouldn’t try to self-diagnose or treat a focal seizure, since seizures are often a sign of serious brain conditions. If you or a loved one have a first-time seizure, see a healthcare provider as soon as possible. If you have epilepsy, your healthcare provider can tell you which symptoms or effects mean you need medical care.
Recovery time depends on the types of seizures you have and the treatments you receive. Your healthcare provider can tell you what to expect, including how long it will take you to recover and when you should feel better.
Everyone is at risk for seizures, and they also happen unpredictably, so it’s not possible to prevent them. The best thing you can do is avoid possible causes to reduce the chances of having a seizure.
Some important steps you can take to reduce your risk of having a seizure include:
Many people who have a first focal seizure go on to have unprovoked focal seizures. So, it’s important to talk to your healthcare provider so that they can diagnose the condition and recommend further treatment. Some patients with focal epilepsy may go on to develop “drug-resistant or medically refractory epilepsy.” This means that medications don’t do enough to help. Drug-resistant epilepsy is often treatable with surgery. Be sure to seek guidance from a provider with expertise in epilepsy surgery.
For provoked seizures, your risk of having another depends on why you had the first one. If the cause was treatable or curable, it’s likely you won’t have another (unless the same cause happens again).
For unprovoked seizures, the vast majority will come under control with an appropriate antiseizure medication. However, if focal seizures continue, it’s important to seek care at an epilepsy center. It’s possible for epilepsy to go into remission and for you to remain seizure-free for the rest of your life.
The outlook for focal seizures and epilepsy depends on the cause, severity and if antiseizure medications help. Overall, focal seizures aren't dangerous, but they can turn into tonic-clonic seizures that are dangerous if they last too long or happen too often.
For the most part, focal seizures have a positive outlook with medications or surgery.
Your healthcare provider is the best person to tell you more about the outlook and what you can expect with seizures and epilepsy. They can provide information relevant to your condition and situation and guide you on what you can do to help yourself with these conditions.
There's a small risk of sudden unexpected death in epilepsy (SUDEP) for people with this condition. Experts suspect SUDEP happens because of heart rhythm malfunctions or breathing problems, but the actual cause is unknown.
For people with controlled (treated) epilepsy, the death rate each year is about 1 person out of every 1,000. For people with uncontrolled (poorly treated) epilepsy, the death rate each year is about 2 out of every 1000 per year.
If you've had one focal seizure in the past, it's important to seek medical advice so that appropriate tests can be done. If you have continued seizures, it’s extremely important that you seek care from an epilepsy center that has expertise in advanced testing for people with uncontrolled epilepsy. This is because, over time, seizures can cause changes in your brain that make it easier for more seizures to happen and affect how well you think and remember things. In addition, uncontrolled seizures are linked to a higher chance of other brain conditions like depression and anxiety. Early diagnosis and treatment can help with that.
If a healthcare provider diagnoses you with epilepsy, you can still do the following to help yourself:
If you’ve never had a seizure before, you should go to the hospital if you pass out unexpectedly or for an unknown reason. If you’re alone and think you’ve had a seizure, contact your healthcare provider as soon as possible.
For people who have epilepsy, it’s often not necessary to call an ambulance or go to the hospital after a seizure. However, they might still need medical care or treatment for seizure-related injuries or prolonged seizures (seizures lasting more than two minutes).
A note from Cleveland Clinic
Focal seizures can cause a wide range of symptoms, many of which are confusing or scary if you’ve never experienced them before. These seizures also happen often in children, which can be frightening for children and parents alike. However, focal seizures and epilepsy are often treatable. In many cases, children with focal epilepsy will outgrow the condition and remain seizure-free for the rest of their lives. Adults also commonly live with focal seizures and epilepsy, and with treatment and care, many can live their lives with minimal effects from their condition.
Last reviewed by a Cleveland Clinic medical professional on 04/29/2022.
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