Epilepsy

Epilepsy  also known as a seizure disorder — is a brain condition that causes recurring seizures. There are many types of epilepsy. In some people, the cause can be identified. In others, the cause is not known.

Epilepsy is common. It's estimated that 1.2% of people in the United States have active epilepsy, according to the Centers for Disease Control and Prevention. Epilepsy affects people of all genders, races, ethnic backgrounds and ages.

Seizure symptoms can vary widely. Some people may lose awareness during a seizure while others don't. Some people stare blankly for a few seconds during a seizure. Others may repeatedly twitch their arms or legs, movements known as convulsions.

Having a single seizure doesn't mean you have epilepsy. Epilepsy is diagnosed if you've had at least two unprovoked seizures at least 24 hours apart. Unprovoked seizures don't have a clear cause.

Treatment with medicines or sometimes surgery can control seizures for most people with epilepsy. Some people require lifelong treatment. For others, seizures go away. Some children with epilepsy may outgrow the condition with age.

Symptoms

Seizure symptoms vary depending on the type of seizure. Because epilepsy is caused by certain activity in the brain, seizures can affect any brain process. Seizure symptoms may include:

• Temporary confusion.

• A staring spell.

• Stiff muscles.

• Uncontrollable jerking movements of the arms and legs.

• Loss of consciousness.

• Psychological symptoms such as fear, anxiety or deja vu.

Sometimes people with epilepsy may have changes in their behavior. They also may have symptoms of psychosis.

Most people with epilepsy tend to have the same type of seizure each time. Symptoms are usually similar from episode to episode.

Warning signs of seizures

Some people with focal seizures have warning signs in the moments before a seizure begins. These warning signs are known as aura.

Warning signs might include a feeling in the stomach. Or they might include emotions such as fear. Some people might feel deja vu. Auras also might be a taste or a smell. They might even be visual, such as a steady or flashing light, a color, or a shape. Some people may experience dizziness and loss of balance. And some people may see things that aren't there, known as hallucinations.

Seizures are classified as either focal or generalized, based on how and where the brain activity causing the seizure begins.

When seizures appear to result from activity in just one area of the brain, they're called focal seizures. These seizures fall into two categories:

• Focal seizures without loss of consciousness. Once called simple partial seizures, these seizures don't cause a loss of awareness, also known as consciousness. They may alter emotions or change the way things look, smell, feel, taste or sound. Some people experience deja vu. This type of seizure also may result in involuntary jerking of a body part, such as an arm or a leg. And focal seizures may cause sensory symptoms such as tingling, dizziness and flashing lights.

• Focal seizures with impaired awareness. Once called complex partial seizures, these seizures involve a change or loss of consciousness. This type of seizure may seem like being in a dream. During a focal seizure with impaired awareness, people may stare into space and not respond in typical ways to the environment. They also may perform repetitive movements, such as hand rubbing, chewing, swallowing or walking in circles.

Symptoms of focal seizures may be confused with other neurological conditions, such as migraine, narcolepsy or mental illness. A thorough exam and testing are needed to tell if symptoms are the result of epilepsy or another condition.

Focal seizures may come from any lobe of the brain. Some types of focal seizures include:

• Temporal lobe seizures. Temporal lobe seizures begin in the areas of the brain called the temporal lobes. The temporal lobes process emotions and play a role in short-term memory. People who have these seizures often experience an aura. The aura may include sudden emotion such as fear or joy. It also may be a sudden taste or smell. Or an aura may be a feeling of deja vu, or a rising sensation in the stomach. During the seizure, people may lose awareness of their surroundings. They also may stare into space, smack their lips, swallow or chew repeatedly, or have movements of their fingers.

• Frontal lobe seizures. Frontal lobe seizures begin in the front of the brain. This is the part of the brain that controls movement. Frontal lobe seizures cause people to move their heads and eyes to one side. They won't respond when spoken to and may scream or laugh. They might extend one arm and flex the other arm. They also might make repetitive movements such as rocking or bicycle pedaling.

• Occipital lobe seizures. These seizures begin in the area of the brain called the occipital lobe. This lobe affects vision and how people see. People who have this type of seizure may have hallucinations. Or they may lose some or all of their vision during the seizure. These seizures also might cause eye blinking or make the eyes move.

Generalized seizures

Seizures that appear to involve all areas of the brain are called generalized seizures. Generalized seizures include:

• Absence seizures. Absence seizures, previously known as petit mal seizures, typically occur in children. Symptoms include staring into space with or without subtle body movements. Movements may include eye blinking or lip smacking and only last 5 to 10 seconds. These seizures may occur in clusters, happening as often as 100 times a day, and cause a brief loss of awareness.

• Tonic seizures. Tonic seizures cause stiff muscles and may affect consciousness. These seizures usually affect muscles in the back, arms and legs and may cause the person to fall to the ground.

• Atonic seizures. Atonic seizures, also known as drop seizures, cause a loss of muscle control. Since this most often affects the legs, it often causes sudden falls to the ground.

• Clonic seizures. Clonic seizures are associated with repeated or rhythmic jerking muscle movements. These seizures usually affect the neck, face and arms.

• Myoclonic seizures. Myoclonic seizures usually appear as sudden brief jerks or twitches and usually affect the upper body, arms and legs.

• Tonic-clonic seizures. Tonic-clonic seizures, previously known as grand mal seizures, are the most dramatic type of epileptic seizure. They can cause a sudden loss of consciousness and body stiffening, twitching and shaking. They sometimes cause loss of bladder control or biting of the tongue.

To diagnose epilepsy, your healthcare professional reviews your symptoms and medical history. You may have several tests to diagnose epilepsy and to detect the cause of seizures. They may include:

• A neurological exam. This exam tests your behavior, movements, mental function and other areas. The exam helps diagnose epilepsy and determine the type of epilepsy you may have.

• Blood tests. A blood sample can detect signs of infections, genetic conditions or other conditions that may be associated with seizures.

• Genetic testing. In some people with epilepsy, genetic testing may give more information about the condition and how to treat it. Genetic testing is most often performed in children but also may be helpful in some adults with epilepsy.

You also may have brain imaging tests and scans that detect brain changes:

• Electroencephalogram (EEG). This is the most common test used to diagnose epilepsy. In this test, small metal discs called electrodes are attached to your scalp with an adhesive or cap. The electrodes record the electrical activity of your brain.
  If you have epilepsy, it's common to have changes in the pattern of brain waves. These changes occur even when you're not having a seizure. Your healthcare professional may monitor you on video during an EEG to detect and record any seizures. This may be done while you're awake or asleep. Recording the seizures may help determine what kind of seizures you're having or rule out other conditions.
  The test may be done in a healthcare professional's office or the hospital. Or you may have an ambulatory EEG. The EEG records seizure activity over the course of a few days at home.
  You may get instructions to do something that can cause seizures, such as getting little sleep prior to the test.

• High-density EEG. In a variation of an EEG test, you may have a high-density EEG. For this test, electrodes are placed closer together compared with a conventional EEG. High-density EEG may help more precisely determine which areas of your brain are affected by seizures.

• Computerized tomography (CT) scan. A CT scan uses X-rays to obtain cross-sectional images of your brain. CT scans can detect tumors, bleeding or cysts in the brain that might be causing epilepsy.

• Magnetic resonance imaging (MRI). An MRI uses powerful magnets and radio waves to create a detailed view of the brain. Like a CT scan, an MRI looks at the structure of the brain to detect what may be causing seizures. But an MRI provides a more detailed look at the brain than a CT scan.

• Functional MRI (fMRI). A functional MRI measures the changes in blood flow that occur when specific parts of the brain are working. This test may be used before surgery to identify the exact locations of critical functions, such as speech and movement. This allows surgeons to avoid those areas while operating.

• Positron emission tomography (PET). PET scans use a small amount of low-dose radioactive material. The material is injected into a vein to help visualize metabolic activity of the brain and detect changes. Areas of the brain with low metabolism may indicate places where seizures occur.

• Single-photon emission computerized tomography (SPECT). This type of test is used if MRI and EEG didn't pinpoint the location in the brain where the seizures start.
  A SPECT test uses a small amount of low-dose radioactive material. The material is injected into a vein to create a detailed, 3D map of blood flow during seizures. Areas of higher than typical blood flow may indicate areas where seizures occur.
  Another type of SPECT test called subtraction ictal SPECT coregistered to MRI (SISCOM) may provide even more-detailed results. The test overlaps the SPECT results with brain MRI results.

• Neuropsychological tests. These tests assess thinking, memory and speech skills. The test results help determine which areas of the brain are affected by seizures.

Along with your test results, a combination of other techniques may be used to help pinpoint where in the brain seizures start:

• Statistical parametric mapping (SPM). SPM looks at the areas of the brain with increased blood flow during seizures. It's compared to the same areas of the brains of people who don't have seizures. This provides information about where seizures begin.

• Electrical source imaging (ESI). ESI is a technique that takes EEG data and projects it onto an MRI of the brain. This is done to show areas where seizures are occurring. This technique provides more-precise detail than does EEG alone.

• Magnetoencephalography (MEG). MEG measures the magnetic fields produced by brain activity. This helps find the potential areas where seizures start. MEG can be more accurate than EEG because the skull and tissue surrounding the brain interfere less with magnetic fields. MEG and MRI together provide images that show areas of the brain both affected by seizures and not affected by seizures.

Diagnosis of your seizure type and where seizures begin gives you the best chance for finding an effective treatment.