Epilepsy is a group of brain disorders that cause seizures. Important things to know:
- Epilepsy can affect anyone at any age, but most people are diagnosed before age 2 or after age 65.
- Early diagnosis and treatment can control seizures and prevent potentially life-threatening complications.
- Medications can stop seizures in about 70% of patients.
What is epilepsy?
Epilepsy is a complex group of neurologic (brain and nervous system) disorders. Surges of electrical activity in the brain cause repeated seizures. These bursts of uncontrolled, unusual brain cell activity can affect your:
Epilepsy and seizures can vary from mild to severe. Episodes can range from blank stares lasting a few seconds to unconsciousness and convulsions lasting several minutes.
A person is diagnosed with epilepsy after at least two seizures that have no other identifiable cause. Someone can also be diagnosed after one seizure if factors show a high likelihood of repeat seizures.
Who gets epilepsy?
Epilepsy can affect anyone. About 3 million adults and 470,000 children in the U.S. were living with epilepsy in 2015, according to the Centers for Disease Control and Prevention. That’s roughly one in 100 people.
Key facts about epilepsy include:
- Frequency: Epilepsy is the fourth most common neurologic condition in the U.S., after migraine, stroke and Alzheimer’s disease.
- Onset: The disorder is most often diagnosed before age 20. It’s most common in children under age 2 and adults over age 65.
- Gender: Men are slightly more likely than women to develop epilepsy.
- Race and ethnicity: Epilepsy affects people of all races and ethnicities around the world. Some groups have a slightly higher or lower risk, but the differences are small.
- Heredity: Genetic defects related to epilepsy can be passed down in families. Certain types of epilepsy are more likely to have a genetic cause. Experts are still researching possible genetic causes. Learn about genetic testing at OHSU.
If you have a seizure, especially more than one, it’s important to see your doctor. Early diagnosis is the key to controlling seizures. Seizures can cause potentially life-threatening complications, such as:
- Risk of drowning
- Car accidents
- Problems during pregnancy
- Emotional disorders such as anxiety and depression
- Status epilepticus — a long seizure (five minutes or more) or a series of seizures without regaining consciousness
- Sudden unexpected death in epilepsy (SUDEP)
Learn how we diagnose epilepsy at the OHSU Comprehensive Epilepsy Center.
Symptoms of epilepsy
Symptoms vary based on the type of seizure and the part of the brain affected. Because these symptoms overlap with other conditions, it’s important to see your doctor to find the cause.
Common signs and symptoms include:
- Unusual eye movement, such as staring, repetitive blinking, or looking up or to the side
- Sudden, temporary confusion
- Loss of consciousness or alertness
- Uncontrollable movements, such as jerking or twitching
- Rigid muscles
- Difficulty talking
Before a seizure, some people with epilepsy experience warning signs, known as auras. An aura is a change in behavior, feeling, sensation or thought that can be similar with each seizure.
What causes epilepsy?
Not everyone with risk factors will develop epilepsy, and people can develop epilepsy without any risk factors. In addition, doctors can’t identify the cause in about half of cases.
When the cause is known, the most common factors are:
- Brain infections such as meningitis or viral encephalitis
- Head trauma, such as a concussion or more traumatic brain injury
- Stroke or blocked blood supply to part of the brain
- A brain tumor
Other causes and risk factors include:
- Neurologic disorders such as autism; or Alzheimer’s disease or another type of dementia
- Injury to an unborn baby, such as brain damage from lack of oxygen, poor nutrition, or an injury or infection affecting the mother
- An inherited genetic defect
- Seizures in childhood, especially long-lasting ones
Find out more about OHSU genetic testing and counseling for neurologic disorders at our Neuro Genetics Clinic.
Not everyone with epilepsy has triggers — things that can set off a seizure. For those who do, triggers can include:
- Sleep deprivation
- Alcohol or drug use
- Video games, flashing lights, or bold, contrasting patterns
- Missed medications
- Menstruation or other hormonal changes
- Illnesses or fevers
Types of epilepsy
Epilepsy includes several syndromes identified by type of seizure and symptoms. Common epilepsy syndromes include:
Some epilepsy syndromes involve focal seizures, which affect only part of the brain:
- Benign rolandic epilepsy: Thought to be inherited, this syndrome makes up about 15% of epilepsy cases in children. Seizures typically stop by age 15. Seizures can last up to two minutes, and children remain conscious.
- Panayiotopoulos syndrome: This childhood epilepsy starts between ages 3 and 10. Seizures can last 20 to 60 minutes and often occur during sleep. Seizures stop after about three years.
- Rasmussen’s syndrome: The immune system attacks brain cells and causes inflammation that can lead to brain damage. People often need surgery because medications can’t control the seizures well.
- Doose syndrome: Also known as myoclonic astatic epilepsy, this type starts in early childhood. Medications might not manage it effectively, but dietary therapy can work well.
- Juvenile absence epilepsy: JAE usually begins between ages 10 and 17. It is a lifelong condition requiring medication. JAE can cause attention, concentration and memory issues. Treatment can improve symptoms.
- Juvenile myoclonic epilepsy: JME is the most common generalized epilepsy syndrome that starts in mid- to late childhood, from ages 5 to 16. Medications usually control this inherited syndrome well.
- Infantile spasms, also known as epileptic spasms or West syndrome: This syndrome begins in infants 4 to 6 months old. It requires early treatment to avoid issues with learning, thinking, behavior and development.
- Lennox-Gastaut syndrome: This syndrome usually starts in childhood and lasts into adulthood. It is difficult to manage with medications and can result in problems with thinking and behavior.
- Frontal lobe epilepsy: This syndrome may be inherited, and its seizures can usually be controlled with medications. It can affect various body parts, depending on where in the frontal lobe the seizures start.
- Temporal lobe epilepsy: This type is the most common syndrome related to focal (partial) seizures. Because the temporal lobe controls many vital functions, seizures in this part of the brain can dramatically affect quality of life.
Types of seizures
The world’s main scientific organization dedicated to epilepsy, the International League Against Epilepsy, issued a 2017 revised classification of seizures. The classification defines seizures in three main categories.
The first category describes seizure onset, or how seizures start in the brain. Seizure onset indicates possible causes, and it guides treatment decisions.
- Focal seizures start on one side or part of the brain.
- Generalized seizures involve both sides of the brain.
- Unknown onset for seizures of unknown origin. Doctors can adjust the type if they find the onset area later.
- Focal to bilateral seizures begin on one side or part of the brain before spreading to both sides.
This category describes the person’s level of awareness during a seizure. Gauging awareness is important to keeping the person safe and determining the type of seizure.
- Focal aware seizures: The person is awake and aware, even if they are unable to speak.
- Focal impaired awareness: The person is not completely aware, even if they are conscious.
- Unknown awareness: No one else was around to determine whether the person was aware.
- Generalized seizures: The person’s awareness or consciousness is always affected.
This category describes whether seizures begin with movement. Movement during seizures helps doctors determine the type. Seizures with onsets that are focal, generalized or unknown can all have motor or non-motor symptoms.
Motor symptoms include:
- Rhythmic jerking movements
- Weakened or limp muscles
- Tense or rigid muscles
- Muscle twitching or spasms
- Repetitive movements, such as hand clapping or rubbing, lip smacking, chewing or running
Non-motor symptoms include:
- Brief twitches in the eyelids or another area of the body
- Changes in sensation, emotions or thinking
- Autonomic functions, such as gastrointestinal sensations, feelings of heat or cold, goose bumps or rapid heartbeat
- Lack of movement, known as behavior arrest
Other categories of seizure symptoms include:
- Absence: Previously known as a petit mal seizure, this generalized-onset seizure results in a short staring “spell” that may include minor eye movements. Absence seizures usually last less than 10 seconds. The person has impaired awareness during the seizure.
- Atonic: The muscles suddenly go limp, and the person’s head or body may go limp or fall. Atonic seizures can be generalized or focal onset. They have motor symptoms and involve impaired awareness.
- Atypical absence: These generalized-onset seizures differ from typical absence seizures because they involve slight facial or hand movements and can last 20 seconds or longer.
- Behavior arrest: In this focal, non-motor seizure type, the person freezes and has impaired awareness.
- Clonic: Clonic seizures have motor symptoms such as repetitive jerking movements. They can be either focal or generalized onset and can last from a few seconds up to two minutes.
- Epileptic spasms: Also known as infantile spasms or West syndrome, this type can be focal or generalized onset, and involves motor symptoms.
- Myoclonic: These seizures can be either focal or generalized onset. They involve rapid, short periods of muscle jerking or twitching. They may come with impaired awareness.
- Tonic: The person experiences sudden muscle stiffness and is usually aware. Tonic seizures can be either focal or generalized onset and usually last less than 20 seconds.
- Tonic-clonic: Previously known as a grand mal seizure, this motor seizure usually begins as a generalized-onset seizure, but it can also start as a focal to bilateral seizure. The person loses consciousness, and all the muscles stiffen before jerking movements begin.
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