Nerve cells in the brain pass signals among themselves using both electrical current and chemicals. In a seizure, the brain’s electricity is not passed in an organized way from one cell to the next, but spreads over a cluster of cells or the whole brain all at once.
When only a portion of the brain is involved, the seizures are called partial seizures or focal seizures.
These seizures vary tremendously in their effects on the person’s movement, sensation or behavior depending on which area of brain is involved.
Some partial seizures are associated with a change in consciousness, even though the person might appear to be awake and his or her eyes may be open.
In this type of seizure, called a complex partial seizure, the affected person is unaware of the people nearby during the event, is not aware of his or her own movements or behaviors during the seizure, and does not remember the seizure after it occurs.
When the person having a partial seizure is aware of having a seizure, is aware of his or her surroundings and remembers the event afterward, the seizure is classified as a simple partial seizure.
Sometimes a seizure may begin as a partial seizure but change part way through the event to involve the whole brain in the seizure activity, ending with arm and leg movements on both sides and loss of consciousness.
When this happens, it is called a generalized seizure.
A person who has seizures repeatedly is said to have epilepsy. In 70% of cases, the cause of epilepsy cannot be found.
Sometimes, epilepsy can be caused by scar tissue or a brain infection that can interfere with the brain’s electrical signaling. Scar tissue in the brain can be caused by head injury, tumor, stroke or surgery.
A partial seizure can imitate any type of behavior or sensation that the brain can cause, depending on the part of the brain that the seizure activates.
Seizures tend to occur in the same area of brain over and over, so symptoms in one person seem very similar from one time to the next. Examples of the symptoms of partial seizures include:
- Abrupt jerking muscle movements in an arm or leg
- Chewing or other mouth or tongue movements, or pulling or fumbling with clothing without a purpose
- A blank stare with no apparent awareness of one’s surroundings
- A sudden feeling of fear, joy or rage that comes without reason
- Repeating a phrase or word
- A change in vision or a hallucination (seeing something that is not real)
- A sensation of smell or taste, usually unpleasant, that does not come from a real object or food
- Sudden loss of balance or dizziness
- After a seizure, a person may be disoriented for a few minutes.
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.
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.
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.
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
- 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.
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 are involved with:
- Processing information from the different senses in the body (seeing, hearing, touching, tasting and smelling)
- Processing language
- 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
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.
Partial seizures can be difficult to diagnose with certainty because they vary so much from one person to another. It is helpful for the doctor to hear a detailed description from the person who is experiencing the events and from people who have seen them occur.
The doctor will also review medical history of problems that can result in brain injury, including brain injury before or during birth.
A physical examination with testing of neurological function will check for evidence of brain disease or brain injury that could result in seizures.
Usually the brain’s electrical activity pattern is tested with an electroencephalogram (EEG) to see if any areas of the brain are conducting electricity in an abnormal way.
If the EEG is abnormal, it can confirm suspicions that seizures are occurring.
A normal EEG is much less helpful, since many patients with seizures that keep returning have normal EEGs in between events.
A seizure usually lasts no longer than a minute or two. Seizures lasting longer than five minutes require emergency medical attention. Confused thinking may follow a seizure, and this can last for several minutes.
If you have epilepsy, the best way to prevent seizures is to take prescribed seizure medicines without missing doses.
You should also get enough sleep each night, don’t fast and avoid drinking too much alcohol. Even when medicine is working well, however, some seizures cannot be prevented.
If you have seizures, even if you are taking medication, you should avoid driving a motor vehicle until seizures are completely controlled.
Sometimes it is reasonable to resume driving after discussion with a physician if you have not had seizures for several months. Driving restrictions for people with seizures vary in the United States from state to state.
A variety of medicines can be used on a long-term basis to prevent seizures or decrease their frequency.
Commonly used medicines to treat partial seizures include carbamazepine (Tegretol and other brand names), phenytoin (Dilantin) and valproate (Depakote), lamotrigine (Lamictal), oxcarbazepine (Trileptal), gabapentin (Neurontin) and topiramate (Topamax). Seizure medicines require close supervision by a doctor, so that the dose can be adjusted as needed and side effects monitored.
If you are treated with an anti-seizure medicine, do not stop taking the medicine abruptly, because seizures can be triggered by this sudden withdrawal.
When To Call a Professional
If you are experiencing periodic episodes that could be seizures, you should be evaluated by a doctor. If you are a woman who is considering becoming pregnant, discuss your seizure history and your medications with your doctor before attempting to get pregnant.
If you witness another person having a partial seizure, it is not necessary to call a doctor right away. You can take the following steps:
- Keep the person safe by removing sharp or hot objects from reach.
- Guide the person away from traffic.
- Reassure others nearby if you know that the person is having a seizure, so that they can understand the situation.
- If the person is agitated, stay a safe distance away.
- If the person has strong, sudden body movements and is lying down, place a cushion or folded clothing under the head. Roll the person onto one side to prevent him or her from choking.
- Do not place any objects into the person’s mouth.
- If the person is confused when the seizure ends, explain what happened in a calm voice.
A seizure that continues for more than five minutes may not stop easily on its own and can become a medical emergency.
Seizures are also more worrisome in pregnant women or in people with diabetes. In these cases, call immediately for advice.
If you have epilepsy and it is not caused by a treatable condition, such as infection, your tendency to have seizures may be lifelong and may require long-term treatment with medicines.
Children with partial seizures frequently stop having seizures as they grow older and may not require continuing treatment.