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Types of Seizures

Seizures take many forms. Before your doctor can prescribe the right treatment, he or she must figure out which type (or types) you have. That's the purpose of all the tests—not just to tell whether you have epilepsy, but also to tell what kind.

Commonly Used Names for Seizure Types

Seizures are generally described in two major groups of seizures, primary generalized seizures and partial seizures. The difference between these types is in how and where they begin. A new way of naming seizures has been developed by epilepsy specialists, but most often these common names are still used.

Primary generalized seizures

Primary generalized seizures begin with a widespread electrical discharge that involves both sides of the brain at once. Hereditary factors are important in many of these seizures.

Partial seizures

Partial seizures begin with an electrical discharge in one limited area of the brain. Many different things can cause partial seizures, for example head injury, brain infection, stroke, tumor, or changes in the way an area of the brain was formed before birth (called cortical dysplasias). Many times, no known cause is found, but genetic factors may be important in some partial seizures.

Partial seizures can be broken down further, depending on whether a person's awareness or consciousness (the ability to respond and remember) is affected.

Source: Steven C. Schachter, MD

Absence Seizures

  • Absence seizures are lapses of awareness, sometimes with staring.
  • They begin and end abruptly, lasting only a few seconds.
  • More common in children.
  • Absence seizures can be so brief that they sometimes are not detected for months.

What is an absence seizure?

An absence seizure causes a short period of “blanking out” or staring into space. Like other kinds of seizures, they are caused by abnormal activity in a person’s brain. You may also hear people call absence seizures petit mal (“PUH-tee mahl”) seizures, although that name is not common anymore.

There are two types of absence seizures:

  • Simple absence seizures: During a simple absence seizure, a person usually just stares into space for less than 10 seconds. Because they happen so quickly, it’s very easy not to notice simple absence seizures — or to confuse them with daydreaming or not paying attention.
  • Complex absence seizures: During a complex absence seizure, a person will make some kind of movement in addition to staring into space. Movements may include blinking, chewing, or hand gestures. A complex absence seizure can last up to 20 seconds.

Absence seizures can also happen with other kinds of seizures.

Absence seizures are so brief that they frequently escape detection.

During a complex absence seizure, people may:

  • Blink over and over so it looks like they’re fluttering their eyelids
  • Smack their lips
  • Make chewing motions with their mouths
  • Rub their fingers together
  • Move their hands

If you’re wondering whether your child is daydreaming or having absence seizures, here are a few key differences to look for.

Daydreaming:

  • Is likely to happen when your child is bored (like during a long class period at school)
  • Usually comes on slowly, with warning (your child may go from paying attention, to a little bit “spacey,” to daydreaming)
  • Can be interrupted
  • Tends to continue until something stops it (like the teacher getting your child’s attention)

Absence seizures:

  • Can happen at anytime, including during physical activity
  • Usually come on very suddenly, without warning
  • Can’t be interrupted
  • End on their own within 20 seconds

Source:  Epilepsy Foundation of America

Atypical Absence Seizures

  • Atypical means unusual or not typical.
  • The person will stare, as in an absence seizure, but also be somewhat responsive.  
  • Many children also have Lennox-Gastaut Syndrome.
  • Medicine can help prevent atypical absence seizures.

What is an atypical absence seizure?

Atypical (a-TIP-i-kul) means unusual or not typical. The person will stare (as they would in any absence seizure) but often is somewhat responsive. Eye blinking or slight jerking movements of the lips may occur. This behavior can be hard to distinguish from the person's usual behavior, especially in those with cognitive impairment. Unlike other absence seizures, these seizures usually cannot be produced by rapid breathing. These seizures usually last 5 to 30 seconds (commonly more than 10), with a gradual beginning and ending.

Source: Epilepsy Foundation of America

Atonic Seizures

  • Atonic means an abrupt loss of muscle tone.
  • They are also known as drop attacks.
  • In some children, only their head suddenly drops.

What is an atonic seizure?

Muscle "tone" is the muscle's normal tension. "Atonic" (a-TON-ik) means "without tone," so in an atonic seizure, muscles suddenly lose strength. The eyelids may droop, the head may nod, and the person may drop things and often falls to the ground. These seizures are also called "drop attacks" or "drop seizures." The person usually remains conscious. These seizures typically last less than 15 seconds. They often start in childhood yet last into adulthood. Many people with atonic seizures are injured when they fall, so they may choose to use protection such as a helmet.

Another name for this type of seizure is "akinetic" (a-kin-ET-ik), which means "without movement."

Source: Epilepsy Foundation of America

Clonic Seizures

  • Clonic means repeated jerking.
  • Clonic seizure movements cannot be stopped by restraining the person.
  • Clonic seizures are rare.
  • Much more common are tonic-clonic seizures, involving jerking and stiffening of the muscles.

What is a clonic seizure?

"Clonus" (KLOH-nus) means rapidly alternating contraction and relaxation of a muscle -- in other words, repeated jerking. The movements cannot be stopped by restraining or repositioning the arms or legs. Clonic (KLON-ik) seizures are rare. Much more common are tonic-clonicseizures, in which the jerking is preceded by stiffening (the "tonic" part). Sometimes tonic-clonic seizures start with jerking alone. These are called clonic-tonic-clonic seizures. These seizures tend to last for a few seconds to a minute.

Brief and infrequent clonic seizures in infants usually disappear on their own within a short time. Other types may need prolonged treatment

Source: Epilepsy Foundation of America

Myoclonic Seizures

  • Myoclonic seizures are brief shock-like jerks of a muscle or group of muscles.
  • They occur in a variety of epilepsy syndromes that have different characteristics.
  • During a myoclonic seizure, the person is usually awake and able to think clearly. 

What is a myoclonic seizure?

Myoclonic (MY-o-KLON-ik) seizures are brief, shock-like jerks of a muscle or a group of muscles. "Myo" means muscle and "clonus" (KLOH-nus) means rapidly alternating contraction and relaxation—jerking or twitching—of a muscle. Usually they don't last more than a second or two. There can be just one, but sometimes many will occur within a short time.

Even people without epilepsy can experience myoclonus in hiccups or in a sudden jerk that may wake you up as you're just falling asleep. These things are normal.

In epilepsy, myoclonic seizures usually cause abnormal movements on both sides of the body at the same time. They occur in a variety of epilepsy syndromes that have different characteristics:

  • Juvenile myoclonic epilepsy: The seizures usually involve the neck, shoulders, and upper arms. In many patients the seizures most often occur soon after waking up. They usually begin around puberty or sometimes in early adulthood in people with a normal range of intelligence. In most cases, these seizures can be well controlled with medication but it must be continued throughout life.
  • Lennox-Gastaut syndrome: This is an uncommon syndrome that usually includes other types of seizures as well. It begins in early childhood. The myoclonic seizures usually involve the neck, shoulders, upper arms, and often the face. They may be quite strong and are difficult to control.
  • Progressive myoclonic epilepsy: The rare syndromes in this category feature a combination of myoclonic seizures and tonic-clonic seizures. Treatment is usually not successful for very long, as the patient deteriorates over time.

Source: Epilepsy Foundation of America

Tonic Seizures

  • In a tonic seizure, the body arms or legs make sudden stiffening movements. 
  • Usually no first aid is needed, unless an injury has occured. 
  • These seizures can occur in anyone but is often seen in people with Lennox-Gastuat Syndrome

What is a tonic seizure?

Muscle "tone" is the muscle's normal tension at rest. In a "tonic" seizure, the tone is greatly increased and the body, arms, or legs make sudden stiffening movements. Consciousness is usually preserved. Tonic seizures most often occur during sleep and usually involve all or most of the brain, affecting both sides of the body. If the person is standing when the seizure starts, he or she often will fall. These seizures usually last less than 20 seconds.

Tonic seizures in Lennox-Gastaut syndrome may become more difficult to control over time. Some patients do achieve a good outcome.

Source: Epilepsy Foundation of America

Tonic Clonic Seizures

  • The tonic-clonic seizure is what most people think of when they think of a convulsive seizure. 
  • A person loses consciousness, muscles stiffen, and jerking movements are seen.
  • These types of seizures usually last 1 to 3 minutes and take much longer for a person to recover. 
  • A tonic-clonic seizure lasting more than 5 minutes is a medical emergency. 

What is a tonic-clonic seizure?

This type is what most people think of when they hear the word "seizure." An older term for them is "grand mal." As implied by the name, they combine the characteristics of tonic seizures and clonic seizures. 

  • The tonic phase comes first: All the muscles stiffen. Air being forced past the vocal cords causes a cry or groan. The person loses consciousness and falls to the floor. The tongue or cheek may be bitten, so bloody saliva may come from the mouth. The person may turn a bit blue in the face.
  • After the tonic phase comes the clonic phase: The arms and usually the legs begin to jerk rapidly and rhythmically, bending and relaxing at the elbows, hips, and knees. After a few minutes, the jerking slows and stops. Bladder or bowel control sometimes is lost as the body relaxes. Consciousness returns slowly, and the person may be drowsy, confused, agitated, or depressed.
  • These seizures generally last 1 to 3 minutes.
  • A tonic-clonic seizure that lasts longer than 5 minutes needs medical help. A seizure that lasts more than 10 minutes, or three seizures without a normal period in between, indicates a dangerous condition called convulsive status epilepticus. This requires emergency treatment.

Source: Epilepsy Foundation of America

Simple Partial Seizures

  • These seizures can be motor seizures that cause change in muscle activity.
  • These seizures can be sensory seizures that cause changes in any one of the senses.
  • These seizures can be autonomic seizures that cause changes in the part of the nervous system that automatically controls bodily functions.
  • These seizures can be psychic seizures that change how people think, feel, or experience things.

What is a simple partial seizure?

Simple partial seizures are usually divided into categories depending on the type of symptoms the person experiences:

Motor seizures:

  • These cause a change in muscle activity. For example, a person may have abnormal movements such as jerking of a finger or stiffening of part of the body.
  • The movements may spread, either staying on one side of the body or extending to both sides. Other examples are weakness, which can even affect speech, and coordinated actions such as laughter or automatic hand movements. 

Sensory seizures:

  • These cause changes in any one of the senses.
  • People with sensory seizures may smell or taste things that aren't there; hear clicking, ringing, or a person's voice when there is no actual sound; or feel a sensation of "pins and needles" or numbness.
  • Seizures may even be painful for some patients. They may feel as if they are floating or spinning in space.
  • They may have visual hallucinations, seeing things that aren't there (a spot of light, a scene with people). They also may experience illusions—distortions of true sensations. For instance, they may believe that a parked car is moving farther away, or that a person's voice is muffled when it's actually clear.

Autonomic seizures:

  • These cause changes in the part of the nervous system that automatically controls bodily functions.
  • These common seizures may include strange or unpleasant sensations in the stomach, chest, or head; changes in the heart rate or breathing; sweating; or goose bumps.

Psychic seizures:

  • These seizures change how people think, feel, or experience things.
  • They may have problems with memory, garbled speech, an inability to find the right word, or trouble understanding spoken or written language.
  • They may suddenly feel emotions like fear, depression, or happiness with no outside reason.
  • Some may feel as though they are outside their body or may have feelings of déja vu ("I've been through this before") or jamais vu ("This is new to me"— even though the setting is really familiar).

Source: Epilepsy Foundation of America

Complex Partial Seizures

  • Complex partial seizures last 1 to 2 minutes.
  • These seizures may have an aura (or warning). 
  • Complex Partial Seizures include automatisms (such as lip smacking, picking at clothes, fumbling), unaware of surroundings or may wander.
  • Many treatment options are available including medicines, diet, surgery and devices.

Here’s a typical story: "Susan's seizures usually occur while she's asleep. She makes a grunting sound, as if she's clearing her throat. Then she'll sit up in bed, open her eyes, and stare. She may clasp her hands together. If I ask her what she's doing, she doesn't answer. After a minute or so, she lies down and goes back to sleep."

What is a complex partial seizure?

  • These seizures usually start in a small area of the temporal lobe or frontal lobe of the brain. They quickly involve other areas of the brain that affect alertness and awareness. So even though the person's eyes are open and they may make movements that seem to have a purpose, in reality "nobody's home." If the symptoms are subtle, other people may think the person is just daydreaming.
  • Some people can have seizures of this kind without realizing anything has happened. The seizure can wipe out memories of events just before or after it.
  • Some of these seizures (usually ones beginning in the temporal lobe) start with a simple partial seizure.
  • Then the person loses awareness and stares blankly.
  • Most people move their mouth, pick at the air or their clothing, or perform other purposeless actions. These movements are called "automatisms" (aw-TOM-ah-TIZ-ums).
  • Less often, people may repeat words or phrases, laugh, scream, or cry. Some people do things during these seizures that can be dangerous or embarrassing, such as walking into traffic or taking their clothes off. These people need to take precautions in advance.
  • Complex partial seizures starting in the frontal lobe tend to be shorter than the ones from the temporal lobe. The seizures that start in the frontal lobe are also more likely to include automatisms like bicycling movements of the legs or pelvic thrusting.
  • Some complex partial seizures turn into secondarily generalized seizures. They usually last between 30 seconds and 2 minutes. Afterward, the person may be tired or confused for about 15 minutes and may not be return to normal function for hours.
  • As for many other kinds of seizures, the outlook depends on whether the cause is known. They may be outgrown or controlled with medication. If medication is not effective, some can be eliminated by epilepsy surgery.

Partial seizures are the most common type of seizure experienced by people with epilepsy.

Source: Epilepsy Foundation of America

Secondarily Generalized Seizures

  • These seizures are called secondary generalized because they start in one area and spread to both sides of the brain. 
  • They usually last 1 to 3 minutes, but it may take a lot longer for a person to recover.
  • A secondary tonic clonic seizure lasting longer than 5 minutes is a medical emergency. 

What is a secondarily generalized seizure?

These seizures are called "secondarily generalized" because they only become generalized (spread to both sides of the brain) after the initial event (a partial seizure) has already begun. They happen when a burst of electrical activity in a limited area (the partial seizure) spreads throughout the brain. Sometimes the person does not recall the first part of the seizure. These seizures occur in more than 30% of people with partial epilepsy.

The generalized, convulsive phase of these seizures usually lasts no more than a few minutes, the same as primary generalized seizures. The preceding partial seizure is usually not very long. Sometimes this part is so brief that it is hard to detect.

Source: Epilepsy Foundation of America

Febrile Seizures

  • Children aged 3 months to 6 years may have tonic-clonic seizures when they have a high fever.
  • More likely to occur if there is a family history of febrile seizures.
  • Most children do not require daily treatment with medication.
  • Among children who have their first febrile seizure before their first birthday, half will have at least one more.
  • Long-term outlook is excellent.

Who gets febrile seizures?

Children aged 3 months to 5 or 6 years may have tonic-clonic seizures when they have a high fever. These are called febrile seizures (pronounced FEB-rile) and occur in 2% to 5% of all children. There is a slight tendency for them to run in families. If a child's parents, brothers or sisters, or other close relatives have had febrile seizures, the child is a bit more likely to have them.

Sometimes the seizure comes "out of the blue." A fever may begin silently in a previously healthy child and a seizure can be the first sign that alerts the family that the child is ill.

What's the outlook?

Among children who have their first febrile seizure before their first birthday, half will have at least one more. Among children who are older than 1 year when the first seizure occurs, about 1 in 4 will have more.

The long-term outlook is excellent, however. The vast majority of children with febrile seizures do not have seizures without fever after age 5.

Risk factors for later epilepsy include:

  • Abnormal development before the febrile seizure.
  • Complex febrile seizures: These are defined as seizures that last longer than 15 minutes, more than one seizure in 24 hours, or seizures in which only one side of the body is affected.
  • Seizures without fever in a parent or a brother or sister.

If the child has none of these risk factors, the chances of later epilepsy are just about the same as for any other child. 

Children with one of these risk factors, have a 2.5% (1 in 40) chance of later epilepsy.

Those with two or three risk factors, have a risk of later epilepsy that ranges from 5% (1 in 20) to over 10%.

In rare cases, febrile seizures that last more than 30 minutes may cause scar tissue in the temporal lobe of the brain. In some of these patients, chronic epilepsy develops, which often can be effectively treated.

Source: Epilepsy Foundation of America

Nonepileptic Seizures

  • Nonepileptic events (also called nonepilepsy seizures) are not caused by electrical activity in the brain. 
  • One in six people also have epilepsy seizures or has had them in the past. 
  • Nonepilepsy seizures may be associated with psychological conditions or other physical problems. 

What are they?

Events that look like seizures but are not due to epilepsy are called "nonepileptic seizures." Some people prefer to use the term "events" rather than seizures. You will see the terms used interchangeably here. A common type is described as psychogenic (si-ko-JEN-ik), which means beginning in the mind. Psychogenic seizures or events are caused by subconscious thoughts, emotions or 'stress', not abnormal electrical activity in the brain. Doctors consider most of them psychological in nature, but not purposely produced. Usually the person is not aware that the spells are not "epileptic." The term "pseudoseizures" has also been used in the past to refer to these events, but we prefer to avoid this term as it is not accurate and has a negative meaning. 

It's important to know that some seizures that are not epilepsy could be caused by other physical problems. These are nonepilepsy seizures too, but not caused by a psychological condition. Further testing is needed to find the exact cause so they can be treated properly.

Source: Epilepsy Foundation of America

Refractory Epilepsy

  • Refractory (uncontrolled) epilepsy is a heavy burden.
  • First it's important to make sure that the diagnosis of epilepsy is correct and that the proper medicines are being used in the best way for each person.
  • The individual with epilepsy needs to look at things they can do to better control their seizures, such as remembering medicines, staying in good health, getting good sleep, minimizing stress and avoiding seizure-precipitating conditions.
  • Non-drug therapies, such as epilepsy surgery, vagus nerve stimulation, responsive neurostimulation, dietary therapies, or experimental clinical trials, may be good options for some people.
  • Only 5% of people (1 out of 20) with refractory epilepsy get better each year. The biggest hope is for new therapies to prevent and cure epilepsy!

What does uncontrolled or refractory seizures mean?

Seizures sometimes are not controlled with seizure medications. A number of different terms may be used to describe these including: “uncontrolled,” “intractable,” “refractory,” or “drug resistant.” How often does this happen?

  • Studies suggest that epilepsy fails to come quickly under control with medicines in about one-third of cases, but the true frequency depends upon the definition of uncontrolled.
  • Most epilepsy specialists agree that refractory epilepsy is epilepsy for which seizures are frequent and severe enough, or the required therapy for them troublesome enough, to seriously interfere with quality of life.
  • However, in more recent years, the epilepsy community has recognized the need to continue striving for ‘no seizures’ and the best control possible.
  • The International League Against Epilepsy (ILAE) has proposed the following definitionofdrugresistant epilepsy and suggests that this term be used instead of the term 'refractory epilepsy'.
    • Drug resistant epilepsy occurs when a person has failed to become (and stay) seizure free with adequate trials of two seizure medications (called AEDs).
    • These seizure medications must have been chosen appropriately for the person’s seizure type, tolerated by the person, and tried alone or together with other seizure medications.

Source: Epilepsy Foundation of America

Gelastic and Dacrystic Seizures

Gelastic and dacrystic seizures are most commonly found in people with hypothalamichamartomas (HH). For many individuals with HH, the first seizure to occur is the gelastic seizure. Gelastic seizures are called the “laughing seizure” because they may look like bouts of uncontrolled laughter or giggling. However, the laughter-like sounds are often forced and combined with a facial contraction similar to a smile or smirk. In some children, the vocalization has a crying quality and the facial contraction resembles a grimace. These crying seizures are called dacrystic seizures.

The gelastic seizures are not associated with any sense of well-being or delight for the individual, but instead can result in a feeling of fear or loss of control. It is not uncommon for gelastic and dacrystic seizures to go undetected for years because of their unusual presentation. Often the seizures go unrecognized until some other seizure type appears. Gelastics often occur as a child is falling off to sleep but can occur throughout the day and night. Infants and children will often be aroused out of sleep by a gelastic seizure, then settle down and go right back to sleep.

Gelastics may present differently with each child; however, some commonalities are evident. There is often an aura, which may appear as a startle, or even a look of panic or fear. The eyes may seem vacant, dilate, or move up and to the left or right. There often is a slight smile that seems somewhat forced and laughter or grunting that seems unusual or not appropriate at that time. In infants, there may be grunting and unusual squirming as well. Some children respond by seeking comfort from a parent or favorite toy for no apparent reason, others will run to a location where they feel safe. Parents have reported gelastics occurring with their children that appear to be triggered by loud noises or fearful responses to sudden actions. Gelastic can also be triggered by excitement and anxiety. 

Gelastic seizures are rarely diagnosed at onset yet they begin in infancy in over one-third of documented patients. Gelastic seizures can occur with very high frequency and amazing regularity. Diagnosis is further complicated by the fact that electroencephalographic studies (EEGs) are often normal or only nonspecifically abnormal in children when only gelastic seizures are present. For many parents, when they hear a description of a gelastic seizure, they realize the activity was indeed there before, yet unrecognized as a seizure.

Source:  Epilepsy Foundation of America

Please contact Epilepsy Foundation of Southeast Tennessee directly if you have any questions at all.