Epilepsy is a brain disorder in which clusters of nerve cells, or neurons, in the brain sometimes signal abnormally. Neurons normally generate electrochemical impulses that act on other neurons, glands, and muscles to produce human thoughts, feelings, and actions.
In epilepsy, the normal pattern of neuronal activity becomes disturbed, causing strange sensations, emotions, and behavior, or sometimes convulsions, muscle spasms, and loss of consciousness known as epileptic seizures. The condition is, therefore, sometimes referred to as a seizure disorder. It affects people in all nations and of all races.
During a seizure, neurons may fire as many as 500 times a second, much faster than the normal rate of about 80 times a second. In some people, this happens only occasionally; for others, it may happen up to hundreds of times a day.
Just as there are many different types of seizures, there are many different types of epilepsy. Doctors have identified hundreds of different epilepsy syndromes -- disorders characterized by a specific set of symptoms that include epilepsy. Some of these syndromes appear to be hereditary. For other syndromes, the cause is unknown.
Epilepsy syndromes are frequently described by their symptoms or by where in the brain they originate. People should discuss the implications of their type of epilepsy with their doctors to understand the full range of symptoms, the possible treatments, and the prognosis.
People with absence epilepsy have repeated absence seizures that cause momentary lapses of consciousness. These seizures almost always begin in childhood or adolescence, and they tend to run in families, suggesting that they may be at least partially due to a defective gene or genes. Some people with absence seizures have purposeless movements during their seizures, such as a jerking arm or rapidly blinking eyes.
Others have no noticeable symptoms except for brief times when they are "out of it." Immediately after a seizure, the person can resume whatever he or she was doing; however, these seizures may occur so frequently that the person cannot concentrate in school or other situations. Childhood absence epilepsy usually stops when the child reaches puberty. Absence seizures usually have no lasting effect on intelligence or other brain functions.
Temporal Lobe Epilepsy
Temporal lobe epilepsy, or TLE, is the most common epilepsy syndrome with focal seizures. These seizures are often associated with auras. TLE often begins in childhood. Research has shown that repeated temporal lobe seizures can cause a brain structure called the hippocampus to shrink over time. The hippocampus is important for memory and learning. While it may take years of temporal lobe seizures for measurable hippocampal damage to occur, this finding underlines the need to treat TLE as early and as effectively as possible.
Neocortical epilepsy is a type of epilepsy characterized by seizures that originate from the brain's cortex, or outer layer.
Children with Lennox-Gastaut syndrome have severe epilepsy with several different types of seizures, including atonic seizures (also called drop attacks), which cause sudden falls. This severe form of epilepsy can be very difficult to treat effectively and is usually present for life.
Rasmussen's encephalitis is a progressive epilepsy type in which half of the brain shows continual inflammation. It sometimes is treated with a radical surgical procedure called hemispherectomy.
Childhood Absence Epilepsy
Some childhood epilepsy syndromes, such as childhood absence epilepsy, tend to go into remission or stop entirely during adolescence, whereas other syndromes (such as juvenile myoclonic epilepsy) usually present for life once they develop. Seizure syndromes do not always appear in childhood, however.
Benign Epilepsy Syndromes
Epilepsy syndromes that are easily treated, do not seem to impair cognitive functions or development, and usually stop spontaneously are often described as benign. Benign epilepsy syndromes include benign infantile encephalopathy and benign neonatal convulsions.
Epilepsy syndromes in which the seizures and/or the person's cognitive abilities get worse over time are called progressive epilepsy.
Several epilepsy types begin in infancy. The most common infantile type is infantile spasms, which are clusters of seizures that usually begin before the age of six months. During these seizures the infant may bend and cry out. Anticonvulsant drugs often do not work for infantile spasms, but the seizures can be treated with ACTH (adrenocorticotropic hormone) or prednisone.
Other Syndromes: Types of Epilepsy?
Other syndromes, such as early myoclonic encephalopathy, include neurological and developmental problems. However, these problems may be caused by underlying neurodegenerative processes rather than by the seizures.
Cause of Epilepsy?
Epilepsy is a disorder with many possible causes. Anything that disturbs the normal pattern of neuron activity -- from illness to brain damage to abnormal brain development -- can lead to seizures.
In about half of all epilepsy cases, the cause is not known.
When the cause of epilepsy is known, it may be one of the following:
Other medical conditions
Epilepsy is not contagious and is not caused by mental illness or mental retardation.
Epilepsy Causes: Understanding the Brain
Epilepsy may develop because of an abnormality in brain wiring, an imbalance of nerve-signaling chemicals called neurotransmitters, or some combination of these factors.
Researchers believe that some people with epilepsy have an abnormally high level of excitatory neurotransmitters that increase neuronal activity, while others have an abnormally low level of inhibitory neurotransmitters that decrease neuronal activity in the brain. Either situation can result in too much neuronal activity and cause epilepsy.
One of the most-studied neurotransmitters involved in epilepsy is GABA, or gamma-aminobutyric acid, which is an inhibitory neurotransmitter. Research on GABA has led to drugs that alter the amount of this neurotransmitter in the brain or change how the brain responds to it. Researchers are also studying excitatory neurotransmitters, such as glutamate.
In some cases, the brain's attempts to repair itself after a head injury, stroke, or other problem may inadvertently generate abnormal nerve connections that cause epilepsy. Abnormalities in brain wiring that occur during brain development also may disturb neuronal activity and lead to epilepsy.
Research has shown that the cell membrane that surrounds each neuron plays an important role in epilepsy. Cell membranes are crucial for a neuron to generate electrical impulses. For this reason, researchers are studying details of the membrane structure, how molecules move in and out of membranes, and how the cell nourishes and repairs the membrane. A disruption in any of these processes may lead to epilepsy. Studies in animals have shown that because the brain continually adapts to changes in stimuli, a small change in neuronal activity, if repeated, may eventually lead to full-blown epilepsy. Researchers are investigating whether this phenomenon, called kindling, may also occur in humans.
In some cases, epilepsy may result from changes in non-neuronal brain cells called glia. These cells regulate concentrations of chemicals in the brain that can affect neuronal signaling.
Genetics as a Cause of Epilepsy
Research suggests that genetic abnormalities may be some of the most important factors contributing to epilepsy. Some types of epilepsy have been traced to an abnormality in a specific gene. Many other types of epilepsy tend to run in families, which suggests that genes influence the brain disorder. Some researchers estimate that more than 500 genes could play a role in this disorder; however, it is increasingly clear that for many forms of epilepsy, genetic abnormalities play only a partial role, perhaps by increasing a person's susceptibility to seizures that are triggered by an environmental factor.
Several types of epilepsy have now been linked to defective genes for ion channels, the "gates" that control the flow of ions in to and out of cells and that regulate neuron signaling. Another gene, which is missing in people with progressive myoclonus epilepsy, codes for a protein called cystatin B. This protein regulates enzymes that break down other proteins. Another gene, which is altered in a severe form of epilepsy called Lafora's disease, has been linked to a gene that helps to break down carbohydrates.
While abnormal genes sometimes cause epilepsy, they also may influence the disorder in subtler ways. For example, one study showed that many people with epilepsy have an abnormally active version of a gene that increases resistance to drugs. This may help explain why anticonvulsant drugs do not work for some people. Genes also may control other aspects of the body's response to medications and each person's susceptibility to seizures, or seizure threshold. Abnormalities in the genes that control neuronal migration -- a critical step in brain development -- can lead to areas of misplaced or abnormally formed neurons, or dysplasia, in the brain that can cause epilepsy. In some cases, genes may contribute to the development of epilepsy, even in people with no family history of the disorder. These people may have a newly developed abnormality, or mutation, in an epilepsy-related gene.
Other Conditions That Can Cause Epilepsy
In many cases, epilepsy develops as a result of brain damage from other disorders. Some of these other disorders include:
Epilepsy is just one of a set of symptoms commonly found in people with these disorders.
Head Injury as a Cause of Epilepsy
In some cases, head injury can lead to seizures or epilepsy. Safety measures, such as wearing seat belts in cars and using helmets when riding a motorcycle or playing competitive sports, can protect people from epilepsy and other problems that result from head injury.
Prenatal Injury and Developmental Problems as Causes of Epilepsy
The developing brain is susceptible to many kinds of injury. Maternal infections, poor nutrition, and oxygen deficiencies are just some of the conditions that may take a toll on the brain of a developing baby. These conditions may lead to cerebral palsy, which often is associated with epilepsy, or they may cause epilepsy that is unrelated to any other disorders. About 20 percent of seizures in children are due to cerebral palsy or other neurological abnormalities.
Abnormalities in genes that control development also may contribute to epilepsy. Advanced brain imaging has revealed that some cases of epilepsy that occur with no obvious cause may be associated with areas of dysplasia in the brain that probably develop before birth.
Poisoning as a Cause of Epilepsy
Seizures can result from exposure to lead, carbon monoxide, and many other poisons. They also can result from exposure to street drugs and from overdoses of antidepressants and other medications.
Epileptic seizures are often triggered by factors such as:
Lack of sleep
Hormonal changes associated with the menstrual cycle.
These seizure triggers do not cause epilepsy, but can provoke first seizures or cause breakthrough seizures in people who otherwise experience good seizure control with their medication. Sleep deprivation in particular is a universal and powerful trigger of seizures.
For this reason, people with epilepsy should make sure to get enough sleep and should try to stay on a regular sleep schedule as much as possible. For some people, light flashing at a certain speed or the flicker of a computer monitor can trigger a seizure; this problem is called photosensitive epilepsy.
Smoking cigarettes also can trigger seizures. The nicotine in cigarettes acts on receptors for the excitatory neurotransmitter acetylcholine in the brain, which increases neuronal firing. Seizures are not triggered by sexual activity, except in rare instances.
Common Symptoms of Epilepsy
Although the symptoms listed in this section are not necessarily indicators of epilepsy, it is wise to consult a healthcare provider if you or a family member experiences one or more of these possible symptoms of epilepsy:
"Blackouts" or periods of confused memory
Episodes of staring or unexplained periods of unresponsiveness
Involuntary movement of arms and legs
"Fainting spells" with incontinence or followed by excessive fatigue
Odd sounds, distorted perceptions, or episodic feelings of fear that cannot be explained.
Few experiences match the drama of a convulsive seizure. A person experiencing severe symptoms of epilepsy may cry out, fall to the floor unconscious, twitch or move uncontrollably, drool, or even lose bladder control.
Within minutes, the attack is over, and the person regains consciousness, but is exhausted and dazed. This is the image most people have when they hear the word epilepsy. However, this type of seizure -- a generalized tonic-clonic seizure -- is only one kind of epilepsy. There are many other types of the brain disorder, each with a different set of symptoms.
Symptoms of Neocortical Epilepsy
Symptoms of neocortical epilepsy can be either focal or generalized. Some of these symptoms of epilepsy may include:
Other symptoms, depending on where in the brain the seizures begin.
One of the best methods for making an epilepsy diagnosis involves compiling a detailed medical history, including symptoms and duration of the seizures. Because people who have experienced a seizure often do not remember what happened, caregivers' accounts of the seizure are vital to doctors making the diagnosis. Tests used to reach an epilepsy diagnosis include electroencephalogram (EEG) monitoring, brain scans, and blood tests.
There are many different treatment options for epilepsy. Current methods can control seizures at least some of the time in about 80 percent of people with epilepsy. However, another 20 percent -- about 600,000 people with epilepsy in the United States -- have intractable seizures, and another 400,000 feel they get inadequate relief from available treatments. These statistics make it clear that improved treatments for epilepsy are desperately needed.
Once epilepsy is diagnosed, it is important to begin treatment as soon as possible. Research suggests that medication and other options may be less successful once seizures and their consequences become established.
The goal of epilepsy treatment is to decrease the number and severity of seizures and minimize drug side effects.
Medications Used to Treat Epilepsy
For about 80 percent of those diagnosed with epilepsy, seizures can be controlled with medicines and/or surgery. Drugs best treat the symptoms of epilepsy, but they do not cure the disease.
Since 1990, a large number of new antiepileptic drugs have been approved, increasing the treatment options available. All of these medications, even the new ones, have some side effects because antiepileptic drugs act directly on the nervous system.
General Information About Medicines for Epilepsy
Things to keep in mind concerning epilepsy medication include the following:
For about 80 percent of those people diagnosed with epilepsy,seizures can be controlled with medications, surgery, or both.
People with epilepsy may take medicine up to four times a day to prevent seizures.
Drugs for epilepsy treat the related symptoms. They do not cure the disease.
There are many different forms of epilepsy, and certain types of medications seem to work best for different types of epilepsy.
Types of Epilepsy Drugs
Since 1990, a large number of new epilepsy medications have been approved, increasing the treatment options for patients and their doctors.
The oldest drugs used in the treatment of epilepsy include phenobarbital, introduced in 1912, and Dilantin® (phenytoin), in use since 1938. Altogether, nearly two dozen different medicines have been approved for epilepsy treatment. Some recent drugs that the U.S. Food and Drug Administration (FDA) has approved include:
When a person starts a new epilepsy medication, it is important to tailor the dosage to achieve the best results. People's bodies react to medicines in different and sometimes unpredictable ways, so it may take time to find the right drug at the right dose to provide optimal control of seizureswhile minimizing side effects.
Side Effects and Interactions With Medication for Epilepsy
Many times, side effects determine the epilepsy medication that a person eventually will take. The specific side effects vary, depending on the drug; however, all medications -- even the new ones -- have some side effects because they act directly on the brain.
Unfortunately, it is impossible for a healthcare provider to know which, if any, side effects people will experience with a medicine that they have never taken. A drug that has no effect or serious side effects at one dose may work well at another dosage. Doctors will usually prescribe a low dose of the new epilepsy medication initially and monitor blood levels of the drug to determine when the best possible dose has been reached.
The need to try different drugs in order to find the best combination to prevent seizures with the fewest possible side effects sometimes gives families the impression doctors are "experimenting" with their loved one's care. But this is the normal procedure for new patients until their seizures are stabilized.
Also, how well a medicine for epilepsy works may be affected by other medications a person is taking. Known as a drug interaction, this relationship may involve how the drug is absorbed, metabolized, and otherwise distributed in the body. The interaction, for example, may speed up or slow down how quickly a medication is eliminated, either making it less effective at preventing seizures because a lower level is present in the blood, or more likely to build up to toxic levels and cause side effects.
Generic versions are available for manyepilepsy medications. The chemicals in generic drugs are exactly the same as in the brand-name drugs, but they may be absorbed or processed differently in the body because of the way they are prepared. Therefore, patients should always check with their doctors before switching to a generic version.
Stopping a Medicine for Epilepsy
Some doctors will advise people with epilepsy to discontinue their medication after two years have passed without a seizure. Others feel it is better to wait for four to five years. Stopping drug therapy should always be done with a doctor's supervision. It is important to continue taking the medicine for as long as the doctor prescribes it.
In addition, people should ask the doctor or pharmacist ahead of time what they should do if they miss a dose.
Stopping epilepsy medication without a doctor's guidance is one of the major reasons people who have been seizure-free start having new seizures. Seizures that result from suddenly stopping treatment can be serious and can lead to status epilepticus. Furthermore, there is some evidence that uncontrolled seizures trigger changes in neurons that can make it more difficult to treat seizures in the future.
The chance that a person will eventually be able to stop taking medicine for epilepsy varies, depending on the person's age and his or her type of epilepsy. More than half of children who go into remission with medication can eventually stop their treatment without having new seizures.
One study showed that 68 percent of adults who had been seizure-free for two years before stopping drugs for epilepsy were able to do so without having more seizures, and 75 percent could successfully discontinue medication if they had been seizure-free for three years.
The odds of successfully stopping epilepsy medication are not as good for:
People with a family history of the condition
Those who need multiple medications
People with focal seizures
Those who continue to have abnormal electroencephalogram (EEG) results while on medication.
Surgery as an Epilepsy Treatment
When a person's seizures cannot be adequately controlled by medications, doctors may recommend that he or she be evaluated for surgery. To decide if a person may benefit from surgery, doctors consider the type or types of seizures he or she has. They also take into account the brain region involved and how important that region is for everyday behavior.
Three broad categories of epilepsy can be treated successfully with surgery. These include:
Doctors generally recommend surgery for epilepsy treatment only after people have tried two or three different medications without success, or if there is an identifiable brain lesion -- a damaged or dysfunctional area -- believed to cause the seizures.
Expectations for the Procedure
A study published in 2000 compared epilepsy surgery to an additional year of treatment with antiepileptic drugs in people with longstanding temporal lobe epilepsy. The results showed that 64 percent of patients receiving surgery became seizure-free, compared to 8 percent of those who continued with medication only.
Because of this study and other evidence, surgery for temporal lobe epilepsy is now recommended when antiepileptic drugs are not effective. However, there is not guidance on how long seizures should occur, how severe they should be, or how many drugs should be tried before surgery is considered. A nationwide study is now underway to determine how soon surgery for temporal lobe epilepsy should be performed.
If a person is considered a good candidate for epilepsy surgery and has seizures that cannot be controlled with available medication, experts generally agree that surgery should be performed as early as possible.
Life After Epilepsy Surgery
It can be difficult for a person who has had years of seizures to fully re-adapt to a seizure-free life if the epilepsy surgery is successful. The person may never have had an opportunity to develop independence, and he or she may have had school and work difficulties that could have been avoided with earlier treatment. Surgery should always be performed with support from rehabilitation specialists and counselors who can help the person deal with the many psychological, social, and employment issues he or she may face.
Even when surgery completely ends a person's seizures, it is important to continue taking seizure medication for some time to give the brain time to re-adapt. Doctors generally recommend epilepsy medication for two years after a successful operation to avoid new seizures.
What Are the Risks?
While surgery can significantly reduce or even halt seizures for some people, it is important to remember that any kind of surgery carries some amount of risk (usually small).
Surgery for epilepsy does not always successfully reduce seizures, and it can result in cognitive or personality changes, even in people who are excellent candidates for surgery. Patients should ask their surgeon about his or her experience, success rates, and complication rates with the procedure they are considering.
Surgery to treat other medical conditions causing seizures (such as a brain tumor).
Living With Epilepsy
Most people living with epilepsy lead outwardly normal lives. Approximately 80 percent of people with epilepsy can be significantly helped by modern therapies, and some may go months or years between seizures.
However, the condition can and does affect daily life for people with epilepsy, as well as their family and their friends. People who experience severe seizures that resist treatment have, on average, a shorter life expectancy and an increased risk of cognitive impairment, particularly if the seizures developed in early childhood. These impairments may be related to the underlying conditions that cause epilepsy or to epilepsy treatment rather than the epilepsy itself.
Behavior and Emotions
It is not uncommon for people with epilepsy, especially children, to develop behavioral and emotional problems. Sometimes these problems are caused by embarrassment or frustration associated with epilepsy. Other problems may result from bullying, teasing, or avoidance in school and other social settings.
In children, these problems can be minimized if parents encourage a positive outlook and independence, do not reward negative behavior with unusual amounts of attention, and try to stay attuned to their child's needs and feelings. Families must learn to accept and live with the seizures without blaming or resenting the affected person.
Counseling services can help families cope with epilepsy in a positive manner. Epilepsy support groups also can help by providing a way for people with epilepsy and their family members to share their experiences, frustrations, and tips for coping with the disorder.
People living with epilepsy have an increased risk of poor self-esteem,depression, and suicide. These problems may be a reaction to a lack of understanding or discomfort about epilepsy that may result in cruelty or avoidance by other people. Many people with epilepsy also live with an ever-present fear that they will have another seizure.
Driving and Recreation
For many people living with epilepsy, the risk of seizures restricts their independence, in particular the ability to drive. Most states and the District of Columbia will not issue a driver's license to someone with epilepsy unless the person can document that they have gone a specific amount of time without a seizure(the waiting period varies from a few months to several years).
Some states make exceptions for this policy when seizures don't impair consciousness, occur only during sleep, or have long auras or other warning signs that allow the person to avoid driving when a seizure is likely to occur.
Studies show that the risk of having a seizure-related accident decreases as the length of time since the last seizure increases. One study found that the risk of having a seizure-related motor vehicle accident is 93 percent less in people who wait at least one year after their last seizure before driving, compared to people who wait for shorter intervals.
The risk of seizures also restricts people's recreational choices. For instance, people with epilepsy should not participate in sports such as skydiving or motor racing, where a moment's inattention could lead to injury. Other activities, such as swimming and sailing, should be done only with precautions or supervision.
Jogging, football, and many other sports are reasonably safe for a person with epilepsy. Studies to date have not shown any increase in seizures due to sports, although these studies have not focused on any activity in particular.
There is some evidence that regular exercise may even improve seizure control in some people.
Sports are often such a positive factor in life that it is best for the person to participate, although the person with epilepsy and the coach or other leader should take appropriate safety precautions. It is important to take steps to avoid potential sports-related problems such as dehydration, overexertion, and hypoglycemia, as these problems can increase the risk of seizures.
Education and Employment
By law, people living with epilepsy or other handicaps in the United States cannot be denied employment or access to any educational, recreational, or other activity because of their seizures. However, one survey showed that only about 56 percent of people living with epilepsy finish high school and about 15 percent finish college -- rates much lower than those for the general population. The same survey found that about 25 percent of working-age people with epilepsy are unemployed.
These numbers indicate that significant barriers still exist for people living with epilepsy in school and work. Restrictions on driving limit the employment opportunities for many people with epilepsy, and many find it difficult to face the misunderstandings and social pressures they encounter in public situations. Antiepileptic drugs also may cause side effects that interfere with concentration and memory.
Children living with epilepsy may need extra time to complete schoolwork, and they sometimes may need to have instructions or other information repeated for them. Teachers should be told what to do if a child in their classroom has a seizure, and parents should work with the school system to find reasonable ways to accommodate any special needs their child may have.
Treating Epilepsy Through Diet
Studies have shown that in some cases, children may experience fewer seizures if they maintain a strict diet rich in fats and low in carbohydrates. This unusual diet, called the ketogenic diet, causes the body to break down fats instead of carbohydrates to survive. This condition is called ketosis.
One study of 150 children whose seizures were poorly controlled with medication found that about one fourth of the children had a 90 percent or better decrease in seizures with the ketogenic diet, and another half of the group had a 50 percent or better decrease in their seizures. Moreover, some children can discontinue the diet after several years and remain seizure-free. The ketogenic diet is not easy to maintain, as it requires strict adherence to an unusual and limited range of foods.
Possible side effects include slow growth due to nutritional deficiency and a buildup of uric acid in the blood, which can lead to kidney stones. People who try the ketogenic diet should seek the guidance of a dietician to ensure that it does not lead to serious nutritional deficiency.
Researchers are not sure how ketosis inhibits seizures. One study showed that a by-product of ketosis called beta-hydroxybutyrate (BHB) inhibits seizures in animals. If BHB also works in humans, researchers may eventually be able to develop drugs that mimic the seizure-inhibiting effects of the ketogenic diet.
Using Biofeedback to Treat Epilepsy
Researchers are studying whether biofeedback -- a strategy in which individuals learn to control their own brain waves -- may be useful in controlling seizures. However, this type of treatment for epilepsy is controversial, and most studies have shown discouraging results.
Supplements as Epilepsy Treatments
Taking large doses of vitamins generally does not help a person's seizures and may even be harmful in some cases. But a good diet and some vitamin supplements, particularly folic acid, may help reduce some birth defects and medication-related nutritional deficiencies.
Use of non-vitamin supplements such as melatonin is controversial and can be risky. One study showed that melatonin may reduce seizures in some children, while another found that the risk of seizures increased measurably with melatonin.
Most non-vitamin supplements, such as those found in health food and other types of stores, are not regulated by the U.S. Food and Drug Administration (FDA), so their true effects -- and their interactions with other drugs -- are largely unknown.
Who Treats Epilepsy?
Doctors who treat epilepsy come from many different fields of medicine. They include:
Doctors who specialize in treating epilepsy are called epileptologists.
People who need specialized or intensive care may get epilepsy treatment at large medical centers and neurology clinics at hospitals or by neurologists in private practice. Many treatment centers are associated with university hospitals that perform research in addition to providing medical care.
Preventing Epilepsy: Prevent Head Trauma
Many cases of epilepsy can be prevented by wearing seat belts and bicycle helmets, putting children in car seats, and practicing other methods of preventing head injury and other trauma.
Finally, identifying the genes for many neurological disorders can provide opportunities for genetic screening and prenatal diagnosis that may ultimately prevent many cases of epilepsy.
Researchers studying epilepsy are examining how and why seizures develop, how they can best be treated or prevented, and how they influence brain development. Researchers are also working to identify genes that may influence epilepsy in some way. Preliminary findings suggest that stem cell transplants may prove beneficial for treating the disease. Other studies are focused on improving the quality of brain scans.