Types of Seizures

Types of Seizures 2021-10-07T11:44:36-04:00

New terms to describe and classify seizures have been developed by the International League Against Epilepsy. This was done to make the names of seizures more accurate, less confusing, and more descriptive of what is happening.

The new terms consider these important areas when describing seizures.

  1. The onset or beginning of a seizure: Where seizures start in the brain tells a lot about what may occur during a seizure, what other conditions or symptoms may be seen, how they may affect someone and, most importantly, what treatment may be best for that seizure type. When we don’t know the onset of a seizure, the wrong treatment may be used. Or a person may not be offered a treatment that has the best chance of helping.
  2. A person’s level of awareness during a seizure: Whether a person is aware or not tells a lot about the type of seizure. It’s also very important to know for a person’s safety.
  3. Whether movements happen during a seizure: Seizures can also be described by whether motor symptoms occur. When no motor symptoms happen, it can be called a non-motor seizure. This level of description does not need to be used all the time, especially when generally describing or talking about seizures. Yet other times you may find the motor terms helpful.

Below we’ll talk about these types in detail. If you’d like to learn more about seizures, feel free to contact us so we can discuss further. 

How Are Seizures Classified Now?

New Classifications of Seizures_OG Twitter Card

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.

  • Focal Onset Aware Seizures: When a person is awake and aware during a seizure, it’s called a focal aware seizure. This used to be called a simple partial seizure.
  • Focal Onset Impaired Awareness: When a person is confused or their awareness is affected in some way during a focal seizure, it’s called a focal impaired awareness seizure. This used to be called a complex partial seizure.

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.

  • As more information is learned, an unknown onset seizure may later be diagnosed as a focal or generalized seizure.

How Are Different Symptoms During A Seizure Described?


Many different symptoms happen during a seizure. This new classification separates them simply into groups that involve movement.

For generalized onset seizures:

  • Motor symptoms may include sustained rhythmical jerking movements (clonic), muscles becoming weak or limp (atonic), muscles becoming tense or rigid (tonic), brief muscle twitching (myoclonus), or epileptic spasms (body flexes and extends repeatedly).
  • Non-motor symptoms are usually called absence seizures. These can be typical or atypical absence seizures (staring spells). Absence seizures can also have brief twitches (myoclonus) that can affect a specific part of the body or just the eyelids.

For focal onset seizures:

  • Motor symptoms may also include jerking (clonic), muscles becoming limp or weak (atonic), tense or rigid muscles (tonic), brief muscle twitching (myoclonus), or epileptic spasms. There may also be automatisms or repeated automatic movements, like clapping or rubbing of hands, lipsmacking or chewing, or running.
  • Non-motor symptoms: Examples of symptoms that don’t affect movement could be changes in sensation, emotions, thinking or cognition, autonomic functions (such as gastrointestinal sensations, waves of heat or cold, goosebumps, heart racing, etc.), or lack of movement (called behavior arrest).

For unknown onset seizures:

  • Motor seizures are described as either tonic-clonic or epileptic spasms.
  • Non-motor seizures usually include a behavior arrest. This means that movement stops – the person may just stare and not make any other movements.

What If I Don’t Know What Type of Seizures I Or My Loved One Have?


It’s not unusual that a person doesn’t know the type of seizure they have. Often seizures are diagnosed based on descriptions of what an observer has seen. These descriptions may not be fully complete or one can’t tell where a seizure begins from this information.

When seizures are difficult to diagnose or seizure medicines are not working to stop seizures, talk to your doctor or treating health care provider.

  • Seeing an epilepsy specialist or having an evaluation at an epilepsy center can help find out if you are having seizures. Not all events are due to epilepsy.
  • An epilepsy center help you explore other treatment options, such as surgery, devices, dietary therapy, new or add-on seizure medications, or a clinical trial.
  • Having tests like an MRI (magnetic resonance imaging) scan to look at the brain and EEG (electroencephalogram) tests to record the electrical activity of the brain are very helpful to diagnose types of seizures and epilepsy properly.
  • Keep asking questions so you get the right tests and right treatment for your type of seizures and epilepsy.

Infantile Spasms


Infantile Spasms (IS) is a rare form of epilepsy that typically begin in the first 4- 8 months of life and is characterized by a flexion (bending and jerking) of the trunk or extremities (arms and legs), and is often mistaken for colic. An episode can range from a subtle head jerk to a flexion that lasts for a few seconds and most often occurs in clusters.

Infantile spasms is typically diagnosed by observing spasms in a child in infancy who also displays specific patterns in their EEG. This pattern is called hypsarrhythmia (hips-A-‘rith-mE-uh) and there is a strong correlation between hypsarrhythmia and the cogitative impairment and developmental delays that are often associated with IS.

There is not much known about what triggers infantile spasms, much more scientific research is needed.  In about 70% of cases, the cause of IS can be linked to a central nervous system (CNS) infection, brain development abnormalities or genetic abnormalities. These are called “symptomatic” causes of IS because they have a cause of origin and can impact the course of treatment selected, which can ultimately affect a child’s outcome.

In approximately 30% of cases, there is no known cause for IS, this is characterized as “cryptogenic”.

While Infantile Spasms are a rare form of epilepsy, it can be identified by distinct characteristics if physician and caregivers are aware of the distinct symptoms.

For more information: www.infantilespasmsinfo.org

Psychogenic Nonepileptic Seizures


Psychogenic nonepilepstic seizures (PNES) are episodes that briefly change a person’s behavior and may look like epileptic seizures. As such you may hear someone refer to them as an event rather than a seizure. They are considered to be psychological rather than the result of a physical cause and are often a challenge to diagnose and treat. This is described as psychogenic, meaning it begins in the mind. It does not mean that the person is causing them on purpose. In one study, fully 25 percent of patients referred to an epilepsy center to be evaluated for surgery had non-epileptic seizures.

A person having non-epileptic seizures may have internal sensations that resemble those felt during an epileptic seizure. The difference in these two kinds of episodes is often hard to recognize by just watching the event, even by trained medical personnel.

The episodes resemble true epileptic seizures in many ways. But there is an important difference. They have characteristics which differ from true seizures in important points, including repeatedly normal EEG readings between seizures; lack of any response to therapeutic levels of anti-epileptic drugs; and violent thrashing of all four limbs, especially if not synchronous, during an episode. Epileptic seizures are caused by abnormal electrical changes in the brain and, in particular, in its outer layer, called the cortex. Non-epileptic seizures are not caused by electrical disruptions in the brain.

Non-epileptic seizures tend to be pleomorphic over time (changing in character) and longer than epileptic seizures. Non-epileptic seizures also occur only in wakefulness, whereas epileptic seizures occur in wake and sleep. Anti-epileptic drugs do not stop non-epileptic seizures.

Non-epileptic seizures may occur in people who also have true epileptic seizures. Successful treatment usually involves psychological counseling and may include treatment with psychiatric medication.

Status Epilepticus


Status epilepticus is said to occur when a seizure lasts too long or when seizures occur close together and the person doesn’t recover between seizures. Just like there are different types of seizures, there are also different types of status epilepticus.

Over the last several decades, the length of seizure that is considered as status epilepticus has shortened. Years ago, a seizure needed to last longer than 20 minutes to be considered status epilepticus. In the last few years, it is now defined as any seizure greater than 5 minutes. This makes sense because most seizures do not last longer than 2 minutes. The longer a seizure lasts, the less likely it will stops on its own without medication. Very long seizures (i.e., status epilepticus) are dangerous and even increase the chance of death. It is important that these long seizures are identified early, so they can be treated early.

Managing Status Epilepticus

  • Ask the doctor if there are any new treatments you can use at home or school to stop a seizure from developing into status epilepticus.
  • Call an ambulance. Do not attempt to transport an actively seizuring person in your car unless an ambulance is not available.
  • Be aware of where the nearest hospital is, how long it takes to get there. If you live a long way from the hospital, you may plan to call earlier than you would if it were closer. If there are several hospitals nearby, ask your doctor in advance which one to call.
  • Consider arranging for standing orders prepared by the doctor to be kept in the emergency room so the seizure can be managed as your doctor directs. Ask for a copy for yourself if you travel out of town.
  • Leave detailed written instructions with babysitters or adult caregivers. If you have been instructed in the use of in-home therapy, make sure that a responsible caregiver also receives instruction.
  • Fortunately, most seizures, even those that are prolonged, end without injury. The important thing is to work with your doctor so that you have a plan to follow when they occur.

Managing Prolonged Seizures in Children
Unless your doctor has advised otherwise, a seizure in a child with epilepsy that ends after a couple of minutes does not usually require a trip to the emergency room.

However, if it lasts more than 5 minutes without any sign of slowing down, is unusual in some way, or if a child has trouble breathing afterwards, appears to be injured or in pain, or recovery is different from usual, call 911 for emergency help.

It is always good to talk to your doctor in advance and plan on what to do if your child has a prolonged seizure so you can have an emergency plan.

Special Circumstances
Some people have convulsive seizures that are prolonged— several minutes—or seizures that sometimes occur in clusters.

New treatments are available that parents or caregivers can administer orally, rectally, intranasal, or by injection to bring this type of seizure to an end. Ask your doctor whether these treatments may be appropriate for you.

Seizures that produce body jerking, staring spells or a state of confusion can also occur in clusters and fail to stop in the usual way.