Epilepsy is a neurological disorder caused by unusual nerve cell activity in the brain. Each year, about 150,000 Americans are diagnosed with the central nervous system disorder that causes seizures. Over a lifetime, one in 26 people will be diagnosed with it.
Seizures can be divided into two main types: Focal (partial) seizures and generalized seizures.
Focal seizures can be further divided into two types: simple focal seizures and dyscognitive focal seizures. Simple focal seizures, also called simple partial seizures, affect only one area of the brain. Memory and cognitive abilities remain unimpaired, but a partial seizure might lead to temporary paralysis, visual changes, or difficulty with simple movements. Less than 15 percent of people with epilepsy have simple focal seizures.
A dyscognitive focal seizure only affects a specific part of the brain. Unlike focal seizures, a dyscognitive focal seizure can cause mental confusion, loss of memory, and loss of awareness during the seizure. People having a complex focal seizure may appear unaware or dazed. More than a third of patients with epilepsy have dyscognitive partial seizures.
The second main type of seizure is generalized seizures. Generalized seizures divide into several subtypes. These include:
- tonic seizure
- clonic seizure
- absence seizure
- atonic seizure
- tonic-clonic seizure
More than 30 percent of people with epilepsy experience generalized seizures.
The area of the brain that is affected by a seizure will determine the symptoms and sensations the seizure causes.
This type of seizure affects only a portion of the brain. For that reason, it’s also sometimes called a partial seizure. Focal seizures have two main categories: simple focal seizures and dyscognitive focal seizures.
Simple focal seizures typically cause few symptoms. The symptoms that this type of seizure causes can be easily mistaken for another condition and overlooked. People may experience slightly shifted emotions or moods, involuntary jerking and twitching in body parts, and unusual sensory experiences, such as seeing flashing lights. Simple focal seizures do not cause memory loss.
Dyscognitive focal seizures cause a loss of consciousness or awareness. People who experience this type of seizure will not be aware of what occurred during the seizure. This type of seizure often causes unusual, repetitive movement. These movements might include hand rubbing, swallowing, walking in circles, or chewing.
All types of generalized seizures affect both sides of the brain. Generalized seizures can be divided into six groups:
Absence seizures. This type of seizure leaves a person briefly unaware of their surroundings and actions. Most people who experience an absence seizure stare blankly until the seizure is over. Some will produce a subtle, repetitive body movement. Absence seizures are also called “petit mal” seizures.
Atonic seizures. This type of seizure causes loss of muscle control. A person experiencing an atonic seizure may suddenly fall or collapse. That’s why this type of seizure is sometimes called a drop seizure.
Clonic seizures. People who have clonic seizures will routinely experience rhythmic, repeated jerking movements. The neck, face, and arms are commonly affected.
Myoclonic seizures. This type of seizure causes sudden jerking movements or twitches. These movements commonly happen in the arms and legs.
Tonic seizures. When this seizure begins, the muscles in the affected area of the body will tighten and stiffen. The arms, legs, and back are commonly affected. Most people who experience a tonic seizure will fall to the ground because of their muscle rigidity.
Tonic-clonic seizures. Commonly called “grand mal” seizures, this type of seizure causes loss of consciousness, as well as violent shaking and body stiffening. Some people will lose control of their bladder and may bite their tongue during the seizure.
One percent of Americans will develop epilepsy in their lifetime. About 2.5 to 3 million people in the U.S. have epilepsy. Additionally, about one in 26 people will experience recurring seizures.
Epilepsy can begin at any age. Studies have not identified a prime diagnosis time, but the incidence rate is highest in children and older adults. Luckily, some children with seizures will eventually grow out of them.
According to the Centers for Disease Control and Prevention, about 2.3 million American adults have epilepsy. More than 467,000 children have been diagnosed with the central nervous system disorder.
Additionally, almost 150,000 people in the U.S. develop epilepsy every year.
Researchers are still unclear if ethnicity plays a role in who develops epilepsy. Studies suggest, however, that non-Latino whites are more commonly affected by generalized epilepsy than people of African-American descent.
This finding points to the possibility that our ancestry may help determine who develops epilepsy.
Overall, no gender is more likely to develop epilepsy than the other. However, it’s possible each gender is more likely to develop certain subtypes of epilepsy. For example, a study found that symptomatic epilepsies are more common in men than women. Cryptogenic seizures (seizures with no known cause) are more frequent in women.
These risk factors give you a higher chance of developing epilepsy:
Age. Epilepsy can begin at any age, but more people are diagnosed at two distinct phases in life: childhood and after age 60.
Brain infections. Infections, such as meningitis, inflame the brain and spinal cord and can increase your risk for developing epilepsy.
Childhood seizures. Some children develop seizures not related to epilepsy during their childhood years. Very high fevers may cause these seizures. As they grow older, some of these children may develop epilepsy.
Dementia. People experiencing a decline in mental function may also develop epilepsy. This is most common in older adults.
Family history. If a close family member has epilepsy, you are more likely to develop this disorder.
Head injuries. Previous falls, concussions, or injuries to your head may cause epilepsy. Taking precautions during activities such as bicycling, skiing, and riding a motorcycle can help protect your head against injury and possibly prevent a future epilepsy diagnosis.
Vascular diseases. Blood vessel diseases and strokes can cause brain damage. Damage to any area of the brain may trigger seizures and eventually epilepsy. The best way to prevent epilepsy caused by vascular diseases is to care for your heart and blood vessels with a healthy diet and regular exercise. Also, avoid tobacco use and excessive alcohol consumption.
Having epilepsy increases your risk for certain complications. Some of these complications are more common than others.
The most common complications include:
Car accidents. Many states do not issue driver’s licenses to people with a history of seizures until they have been seizure-free for a specified period of time. A seizure can cause loss of awareness and affect your ability to control a car. You could injure yourself or others if you have a seizure while driving.
Drowning. People with epilepsy are 15 to 19 times more likely to drown than the rest of the population. That’s because people with epilepsy may have a seizure while in a swimming pool, lake, bathtub, or other body of water. They may be unable to move or may lose awareness of their situation during the seizure. If you swim and have a history of seizures, make sure a lifeguard on duty is aware of your condition. Never swim alone.
Emotional health difficulties. Unfortunately, the emotional toll of epilepsy may be too great for some people to bear alone. Depression, anxiety, and suicidal thoughts and actions are possible complications.
Falling. Certain types of seizures affect your motor movements. You may lose control of your muscle function during a seizure and fall to the ground, hit your head on nearby objects, and even break a bone.
Pregnancy-related complications. Women with epilepsy can get pregnant and have healthy pregnancies and babies, but extra precaution is needed. Some anti-seizure medications can cause birth defects, so you and your doctor need to carefully evaluate your medicines before you plan to get pregnant.
Less common complications include:
Status epilepticus. Severe seizures, ones that are prolonged or happen very frequently, can cause status epilepticus. People with this condition are more likely to develop permanent brain damage.
Sudden unexplained death in epilepsy (SUDEP). Sudden, unexplained death is possible in people with epilepsy, but it is rare. Only two to 18 percent of people with epilepsy die from SUDEP. Doctors do not know what causes SUDEP, but one theory suggests heart and respiratory issues may contribute to the death.
Tests and Diagnosis
Diagnosing epilepsy requires several types of tests and studies to ensure your symptoms and sensations are the result of epilepsy and not another neurological condition. The tests doctors most commonly use include:
Blood tests. Your doctor will take samples of your blood to test for possible infections or other conditions that might explain your symptoms. The test results might also identify potential causes for epilepsy.
EEG. An electroencephalogram (EEG) is a tool that most successfully diagnoses epilepsy. During an EEG, doctors place electrodes on your scalp. These electrodes sense and record the electrical activity taking place in your brain. Doctors can then examine your brain patterns and find unusual activity, which may signal epilepsy. This test can identify epilepsy even when you’re not having a seizure.
Neurological examination. As with any doctor’s office visit, your doctor will want to complete a full health history. They will want to understand when your symptoms began and what you have experienced. This information can help your doctor determine what tests are needed and what types of treatments may help once a cause is found.
CT scan. A computed tomography (CT) scan takes cross-sectional pictures of your brain. This allows doctors to see into each layer of your brain and find possible causes of seizures, including cysts, tumors, and bleeding.
MRI. Magnetic resonance imaging (MRI) takes a detailed picture of your brain. Doctors can use the images created by an MRI to study very detailed areas of your brain and possibly find abnormalities that may be contributing to your seizures.
fMRI. A functional MRI (fMRI) lets your doctors see your brain in very close detail. An fMRI allows doctors to see how blood flows through your brain. This may help them understand what areas of the brain are involved during a seizure.
PET scan. A positron emission tomography (PET) scan uses small amounts of low-dose radioactive material to help doctors see your brain’s electrical activity. The material is injected into a vein and a machine can then take pictures of the material once it has made its way to your brain.
Seventy percent of people with epilepsy can find ease and relief from their symptoms with the most common forms of treatment. Treatment might be as simple as taking an anti-epileptic medication. Others may require more invasive treatments. The most common treatments for epilepsy include:
Medication. Anti-epileptic medicines are very effective for most people. It’s also possible you will be able to discontinue taking these medicines after a certain period of time.
Surgery. In some cases, imaging tests can detect the area of the brain responsible for the seizure. If this area of the brain is very small and well defined, doctors may perform surgery to remove the portions of the brain that are responsible for the seizures. If your seizures originate in a part of the brain that cannot be removed, your doctor may still be able to perform a procedure that can help prevent the seizures from spreading to other areas of the brain.
Vagus nerve stimulation. Doctors can implant a device under the skin of your chest. This device is connected to the vagus nerve in the neck. The device sends electrical bursts through the nerve and into the brain. These electrical pulses have been shown to reduce seizures by 20 to 40 percent.
When to See a Doctor
A seizure can be very scary, especially if it’s happening for the first time. Once you have been diagnosed with epilepsy, you will learn to manage your seizures in a healthy way. However, a few circumstances may require you to seek immediate medical help. These circumstances include:
- injuring yourself during a seizure
- having a seizure that lasts more than 5 minutes
- failing to regain consciousness or not breathing after the seizure ends
- having a high fever in addition to the seizures
- having diabetes
- having a second seizure immediately after a first
- a seizure caused by heat exhaustion