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Understanding Epilepsy Basics

Epilepsy is a brain disorder that causes recurring, unprovoked seizures. Your doctor may diagnose you with epilepsy if you have two unprovoked seizures or one unprovoked seizure with a high risk of more. Not all seizures are the result of epilepsy. Seizures may relate to a brain injury or a family trait, but often the cause is completely unknown.

The word "epilepsy" simply means the same thing as "seizure disorders." It does not state anything about the cause of the person's seizures or their severity.


In the United States, 3.4 million people live with epilepsy, and over 150,000 new cases are diagnosed each year. One in 26 people will develop epilepsy at some point in their life. Epilepsy doesn’t discriminate.


More than half the time, the cause is unknown. When a cause can be found, it is often one of these:

  • Head injury

  • Infection of the brain

  • Stroke

  • Brain tumor

  • Alzheimer’s disease

  • Malformation of an area of the brain

  • Genetic factors


  • A good description of the event and ideally an eyewitness account or video recording is key to determining if the event was a seizure and what kind.

  • A medical history, physical and neurological exam, blood work, and other tests are important. These help diagnose epilepsy and look for other conditions or causes.

  • An EEG is one of the most important tests. It records the brain’s electrical activity. Some patterns of activity are unique to certain types of seizures.

  • Imaging tests (like a CT, MRI, or PET scan) look at the structure and function of the brain. An MRI is needed for anyone with new onset of seizures. PET scans or other advanced imaging may be done later.


Seizures involve sudden, temporary, bursts of electrical activity in the brain that change or disrupt the way messages are sent between brain cells. These electrical bursts can cause involuntary changes in body movement or function, sensation, behavior or awareness.

Every brain has the potential to seize. A person with epilepsy has a lower seizure threshold – this means they are more likely to have seizures than people without epilepsy.

It is important to note the distinction between seizures and epilepsy. A seizure is an event and can be a symptom of other medical problems.


Not all seizures are the same. Many people with epilepsy have more than one type of seizure and may have other symptoms of neurological problems as well. There are now 3 major groups of seizures:

Generalized onset seizures: These seizures affect both sides of the brain or groups of cells on both sides of the brain at the same time. This term was used before and still includes seizures types like tonic-clonic, absence, or atonic to name a few.

Focal onset seizures: The term focal is used instead of partial to be more accurate when talking about where seizures begin. Focal seizures can start in one area or group of cells in one side of the brain.

Unknown onset seizures: When the beginning of a seizure is not known, it’s now called an unknown onset seizure. A seizure could also be called an unknown onset if it’s not witnessed or seen by anyone, for example when seizures happen at night or in a person who lives alone.


Some people may find that seizures occur in a pattern or are more likely to occur in certain situations. Sometimes these connections are just by chance, but other times it’s not. Keeping track of any factors that may come before a seizure (also called seizure triggers) can help you recognize when a seizure may be coming. You can then be prepared and learn how to lessen the chance that a seizure may occur at this time.

Some people will notice one or two triggers very easily. For example, their seizures may occur only during sleep or when waking up. Other people may notice that some triggers bother them only when a lot is going on at once or during a "high risk" time for them, like when they are under a lot of stress or sick.


Epilepsy syndromes are defined by a cluster of features.

These features may include:

  • Type or types of seizures

  • Age at which the seizures begin

  • Causes of the seizures

  • Whether the seizures are inherited

  • The part of the brain involved

  • Factors that provoke the seizures

  • How severe and how frequent the seizures are

  • A pattern of seizures by time of day

  • Certain patterns on the EEG (electroencephalogram), during and between seizures

  • Brain imaging findings, for example, MRI (magnetic resonance imaging) or CT (computed tomography) scan

  • Genetic information

  • Other disorders in addition to seizures

  • The prospects for recovery or worsening



Drugs used to treat epilepsy are called anti-seizure medication.

  • More than 30 anti-seizure medications are currently approved to treat epilepsy.

  •  About 6 in 10 people may control their seizures with the first or second medicine they try.

  • Yet a survey of adults in the community found that 56% still have seizures.

  • Regardless of the numbers, if a person does not get control of seizures in the first year or after the first 2 or 3 medicines are tried, they should be seen by an epilepsy specialist.

  • Options beyond medicines may be possible.

Surgical Lights


Certain types of surgery may be used for people whose seizures do not respond to medication. Surgery may be recommended when a seizure focus can be found and removed without hurting vital functions like speech or movement.


A small device (generator) is implanted under the skin in the left side of the chest. A small thin wire or electrode goes from the generator and is attached to the vagus nerve in the neck. VNS may be an option if surgery doesn’t work or is not right for you. The benefits of the VNS appear to improve over time. For example, about 45% of people have seizures decreased by 50% or more within one to two years


This is another device to treat seizures. It is implanted under the scalp in a small area of the skull or bone surrounding the brain. One or two wires from the device are placed under or on the surface of the brain where seizures start. The device is able to sense a seizure and sends small pulses of electrical current through the wires to help stop or lessen seizures. RNS also may help people who can’t have surgery or when surgery doesn’t work well enough. Like the VNS, the RNS does not cure epilepsy and it may not work right away. Yet it can help stop or lessen the number of seizures a person has by 40% to 60% after one to three years.



DBS is a new type of device that also helps control seizures when surgery doesn’t work or cannot be done. Electrode wires are placed in a specific area of the brain. The device is programmed, like VNS, to give stimulation to interrupt or stop seizures.



Dietary therapies can help control seizures in both children and adults. They are usually used when seizures do not respond to medicine.The most common diet therapy is the ketogenic diet. This is a medically supervised high fat and low carbohydrate diet. There are three other diets that also help control seizures in some people. Most people who use a diet therapy continue taking medicine

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