Types of Epilepsy: A Guide to Epilepsy and Its Presentations
This fact, and the risk of complications from epilepsy and seizures, make understanding the types of epilepsy essential to providing the best outcome.
Read on to find out more about epilepsy and epileptic seizures, including their types, how to identify them, and individual treatment.
Epilepsy or epilepsies refers to a group of chronic neurological disorders due to abnormal nerve cell function.
Clusters of nerve cells in the brain called neurons generate electrical and chemical signals that coordinate bodily and cognitive functions.
With epilepsy, the neurons can sometimes signal unusually, causing seizures.
In addition to different types of epilepsy, there are also different types of seizures that someone with epilepsy may experience.
With treatment, people who experience epilepsy may be able to control their seizures and have a high quality of life.
Clinicians estimate that there are more than 30 different types of seizures. However, clinicians often divide seizures into two main categories of focal seizures and generalized seizures.
Focal onset seizures originate in only one part of the brain. However, they may progress to another part of the brain. These kinds of seizures are called focal to bilateral tonic-clonic seizures.
Clinicians may also describe focal seizures according to where in the brain they first originated — for example, in the frontal lobe or medial temporal lobe.
Symptoms of focal seizure may include:
- motor or sensory sensations
- psychic feelings, such as intense deja vu or memory sensations
- sudden or unexplainable emotions such as joy, anger, sadness
- olfactory, auditory, sensory, or visual hallucinations or feelings of things that are not real
- movements in just one part of the body
- automatism, a repetitious behavior, such as repetitive blinking, twitching, chewing, swallowing, or walking in a circle
Some may experience focal seizures as focal unaware seizures, previously known as simple partial seizures. People may also experience focal impaired awareness seizures, previously known as complex partial seizures.
Focal unaware seizures
Also known as auras, these seizures affect a small part of the brain. You may remain awake during the seizure while experiencing other symptoms.
Focal impaired awareness seizures
Focal impaired awareness seizures may cause you to lose your awareness, make random body movements, and be unable to respond to others. You may not have any memory of the seizure afterward.
Generalized seizures result from neuronal activity that affects both sides of the brain.
This seizure type can cause symptoms such as loss of consciousness, falls, or involuntary muscle contractions.
There are many different kinds of generalized seizures which include:
- Absence seizures: These seizures are particularly common in children. During an absence seizure, a person may stare blankly into space or have the appearance of daydreaming. A person may flutter their eyes or make slight jerking movements of the body without memory of the episode. These seizures can last around 15 seconds and happen several times per day.
- Tonic seizures: During a tonic seizure, a person may lose consciousness, their body may go stiff, and they may fall to the floor.
- Clonic seizures: During a clonic seizure, the limbs may jerk around, and a person may lose control of their bladder or bowel. A person having a clonic seizure may also bite their tongue or cheek and have difficulty breathing.
- Tonic-clonic seizures: Tonic-clonic seizures are when a clonic seizure follows a tonic seizure. Some call these seizures “grand mal” seizures. Tonic-clonic seizures may stop after a few minutes but can last longer.
- Myoclonic seizures: These are seizures that can cause jerking or twitching of the body and limbs.
- Atonic seizures: These seizures occur due to a loss of muscle tone. Atonic seizures can lead to falls or the person’s head dropping involuntarily.
- Febrile seizures: These seizures occur due to fever or infection. They may present as a loss of consciousness, uncontrollable shaking of the limbs, eye rolling, and rigid or stiff limbs.
- Focal to bilateral tonic-clonic seizures: This term refers to when a person experiences both focal seizures and separate generalized seizures.
Sometimes people experience seizures in which clinicians do not know where in the brain the seizure started.
Seizure types could be unknown if the person was unaware of having a seizure, such as sleeping while it happened or being alone with nobody to witness the seizure.
Clinicians may also use this term to describe seizures that they do not have much information about or one that presents unusual symptoms.
Testing methods such as MRI scans might help identify the cause and type of initially unknown seizures.
Some seizures are non-epileptic, meaning they do not occur due to epilepsy. They may outwardly resemble an epileptic episode but have other causes and origins.
Approximately 20–40% of patients that doctors admit to epilepsy monitoring units later receive a diagnosis of psychogenic non-epileptic seizure.
Much like there are many different types of seizures, there are also many different types of epilepsy.
Clinicians may classify epilepsy type according to the type of seizures they experience. For example, someone who experiences primarily generalized seizures may receive a diagnosis of generalized epilepsy or epilepsy with generalized seizures.
Types of epilepsy include:
- focal epilepsy
- generalized epilepsy
- combination focal and generalized epilepsy
- unknown epilepsy
There are also many epilepsy syndromes, which are disorders that include epilepsy as a significant symptom, among other characteristics. There are hundreds of different epilepsy syndromes.
Below are some examples of epilepsy syndromes.
Frontal lobe epilepsy
Frontal lobe epilepsy is an epilepsy syndrome that presents brief focal seizures. These seizures may occur in clusters, soon after each other.
Seizures from frontal lobe epilepsy typically occur during sleep but can also occur during wake time.
Temporal lobe epilepsy
TLE often starts in childhood or adolescence.
It can cause shrinkage and scarring to the hippocampus, a part of the brain that is fundamental to memory and learning.
Seizures can be focal or generalized convulsive seizures, which sometimes occur due to increased temperatures or temperature changes.
Prolonged seizures may affect one side of the body before switching to the other side of the body. Other seizure types may also emerge with age.
This syndrome can provoke several types of seizures, such as atonic, tonic, and absence seizures. Some individuals may also experience prolonged periods of seizures called status epilepticus.
It typically begins in childhood, between 3–5 years old.
Most people with Lennox-Gastaut syndrome experience an intellectual disability or developmental and learning problems.
Epilepsy commonly presents itself in either early childhood or late adulthood.
Fast facts about epilepsy and age
- About 3.4 million people in the United States had epilepsy in 2015. Of this number, 3 million are adults, and 470,000 are children.
- Estimates suggest that around 6 in 1000 children under 17 years old have active epilepsy.
- Epilepsy occurrence increases in people older than 50, with a common cause being cerebrovascular disease.
- About 40–50% of children who have epilepsy will continue to experience epileptic episodes for their entire lives. Lifelong epileptic episodes may have long-term effects, including social, developmental, and health complications.
Common epilepsy syndromes in children
Certain types of epilepsy and seizure are more common than others in children. These can include:
- Benign rolandic epilepsy (BRE): Symptoms of BRE include nighttime seizures that may affect the face and wake the individual. Seizures may also be generalized. It is the most common epilepsy syndrome in children.
- Childhood absence epilepsy: Absence seizures characterize this kind of epilepsy. It may have a genetic component as it can run in families. It may also improve after puberty, although some continue to experience additional types of seizures into adulthood.
- Juvenile myoclonic epilepsy (JME): The word “myoclonic” describes the uncontrollable jerking of the arms and legs, typical of JME seizures. Onset usually begins in adolescence and is a lifelong condition. Seizures may particularly occur during waking or due to triggers such as fatigue, stress, and alcohol consumption.
For children, some epilepsy syndromes may improve over time. In other cases, there may be more long-term effects on social, developmental, and cognitive health.
You should always notify a medical professional after someone experiences a seizure.
However, not every seizure classifies as an emergency. The Centers for Disease Control and Prevention (CDC) recommends calling 911 for anyone who:
- is experiencing their first seizure ever
- has difficulty breathing or waking after a seizure
- has a seizure lasting longer than 5 minutes
- has a seizure soon after the first one
- the person becomes injured during the seizure
- experiences a seizure while in water
- has another underlying health condition, such as diabetes or heart disease
- has a seizure while pregnant
Your doctor may use tests to investigate for epilepsy and also rule out other potential causes of seizures.
Sources of information that a doctor or specialist may use include:
- medical and symptom history
- family history
- blood tests
- imaging and monitoring tests such as an MRI, CT, and PET scans
Neurologists may order an EEG, a noninvasive imaging test, to determine where the epileptic brain activity occurs. A specialist may be able to classify epilepsy or seizure types based on the seizure activity’s location.
A doctor may also order developmental, neurological, and behavioral tests. These procedures can determine how epilepsy impacts the person and may provide indications of the type of epilepsy present.
Epilepsy is a condition that occurs when there is unusual electrical activity in the brain, resulting in seizures. Epilepsy can include many different seizure types, syndromes, and epileptic conditions.
Some epileptic seizures, known as focal seizures, begin in one part of the brain. Others, known as generalized seizures, impact both sides. It is possible to experience a combination of seizure types.
The type of seizure and its symptoms may vary according to epilepsy syndrome.
Identifying the condition causing seizures and epilepsy is essential for diagnosis. A proper diagnosis can help optimize treatment and provide the best outcome.