Introduction to epilepsy research
What is epilepsy?
What is a seizure?
Classification and seizure types
How common is epilepsy?
How is epilepsy diagnosed?
Is epilepsy inherited?
How is epilepsy treated?
How does antiepileptic medication work?
What is epilepsy surgery?
Additional treatment options
What can I do to help improve my memory?
What restrictions does epilepsy impose on daily activities?
First aid for seizures
Research in epilepsy is focused on trying to understand the process that leads the brain to have seizures as well as trying to discover new and better ways to treat epilepsy. Our ability to define the different problems that can lead to epilepsy at genetic, molecular, and cellular levels will help us to target prevention and therapy. For example, recent research suggests that some forms of epilepsy result from disorders in ion channels; drugs that influence ion channels can help to control seizures. Other research has shown that excessive immunological responses (autoimmunity) can irritate brain cells and provoke seizures, and that seizure activity can lead to increased immunological activity.
Epilepsy is a disorder, not a disease. Anything that injures the brain or affects its functions has the potential to cause seizures. Epilepsy research is directed at trying to find common pathways that underlie epilepsy. Large multicenter studies that pool data from many sites may help us to collect a sufficiently powerful set of data to better understand the genetics of why epilepsy is difficult to control in some individuals while others have bad side effects to specific medications.
Increasing public awareness about epilepsy and advocating for patients and families remains critical for improving the quality of lives for people with epilepsy NOW. Our society often discriminates or creates obstacles for individuals with medical problems, especially those with disorders that are misunderstood. And epilepsy is the paradigm of a disorder in which lack of information and misinformation is common among the general population. Increasing awareness can make the school, work, and life with epilepsy much easier and much more productive.
*Orrin Devinsky is Professor of Neurology, Neurosurgery, and Psychiatry at NYU School of Medicine. He directs the NYU Comprehensive Epilepsy Center and the Saint Barnabas Institute of Neurology and Neurosurgery. He also currently directs the Phenome Core for the Epilepsy Phenome Genome Project. Orrin founded Finding A Cure Against Epilepsy and Seizures (FACES) and co-founded epilepsy.com and the Epilepsy Therapy Project. He currently serves as the President of the Epilepsy Research Foundation and has served on boards of the American Epilepsy Society and local and national Epilepsy Foundation. He has published widely in epilepsy and behavioral neurology, with more than 250 articles, 50 chapters and 20 books and monographs.
Epilepsy is a condition of the brain that is characterized by recurrent seizures. Approximately one in ten people will experience at least one seizure during a lifetime. A single seizure, however, is not epilepsy. Epilepsy is a condition that is defined by multiple seizures.
Epilepsy is a seizure disorder. It is not a psychological disorder nor a disease and it is not contagious. The brain is made up of billions of nerve cells or neurons that communicate through electrical and chemical signals. When there is a sudden excessive electrical discharge that disrupts the normal activity of the nerve cells, a seizure may result.
Seizures cause a change in function or behavior. A seizure may take many different forms including a blank stare, muscle spasms, uncontrolled movements, altered awareness, odd sensations, or a convulsion. The location in the brain of the abnormally discharging nerve cells determines the form the seizure will take. Seizures may occur rarely or as often as numerous times a day. If the condition is successfully controlled by medication, a person may be seizure free.
Epilepsy is one of the most common chronic neurological disorders. An estimated 50 million people worldwide have epilepsy. That means approximately one percent of the general population has epilepsy.
Epilepsy can be present at any age although its onset is most often in childhood or in the later years of life. Sometimes those who develop seizures during childhood outgrow their seizures. In the elderly, there is an increased incidence due to strokes and aging of the brain. In more than half of those with epilepsy, seizures can be well controlled with seizure medication.
A seizure is a brief, abnormal, excessive surge of electrical activity in the brain that produces a sometimes noticeable change in behaviour. There are many different types of seizures, which may reflect the area from which the seizure begins (seizure focus) and the pattern in which the abnormal electrical discharge spreads through the brain.
The person may experience body sensations such as “pins and needles”, smells, sounds, fear, depression, distortions of sensory stimuli, momentary jerks or head nods, staring with loss of awareness and convulsive movements.
Seizures usually last seconds to minutes, rarely longer. The period immediately after a seizure, called the “postictal period,” varies depending on the duration, intensity, and type of seizure. The most common symptoms that a person may experience immediately after a convulsive seizure are confusion, muscular ache, headache, and fatigue.
Some people experience what is called an aura.—an “early warning system” for seizures. An aura is a strange sensation or feeling that is in fact a simple partial seizure (see Seizure Types below). Auras may consist of dizziness, an unusual feeling in the stomach, buzzing in the ear, a powerful emotion, or just about any sensation at all. Many people don’t realize they have an aura until they review their symptoms with a physician.
After you have a seizure, try to remember if you noticed anything unusual at the beginning, (such as an unexplained feeling or sensation) and write it down. After a while, if you notice a pattern, then you may have found an early warning system for your seizures.
Identifying an aura can be helpful. You may be able to take quick precautions to ensure safety for when the seizure occurs. Also, the symptoms experienced during an aura may help your physician “localize” your seizures.
Seizure classification is merely descriptive and has no implications regarding cause of the disorder. It is important because it can help determine the type of treatment you require.In order to determine how seizures are classified it is necessary to understand how the brain works.
The brain is like a team of workers. Each member of the team has a certain job to do. This means that certain parts of the brain are responsible for certain duties. One part of the brain is responsible for what we see; another part of the brain is responsible for movement. Other parts of the brain are responsible for speech or smell and taste.
All parts of the brain communicate over a network of cells called “neurons.” Neurons communicate through small electrical charges that travel along nerve pathways similar to electricity in a wire.
A seizure may be classified as a “generalized” seizure if there is an uncontrolled discharge from neurons that affects both sides of the brain from the beginning. If the uncontrolled discharge from neurons occurs in only an isolated part of the brain, it is a “partial” or focal seizure. (Click here for a video on how neurons function during a seizure.)
Generalized seizures begin with a widespread, excessive electrical discharge simultaneously involving both sides of the brain (the whole brain). The principal types of primary generalized seizures are tonic-clonic seizures, absence seizures, myoclonic seizures, clonic seizures, atonic seizures, and tonic seizures.
a) Generalized Tonic-Clonic Seizures (formerly called called Grand Mal) begin with loss of consciousness, a tonic phase (body stiffening), a fall and often a cry caused by air forced through contracted vocal cords. The subsequent clonic phase consists of jerking of the upper and lower limbs. Breathing may be shallow and irregular; skin may become blue because of an arrest of breathing. Tonic-clonic seizures may last several minutes or even longer. Other symptoms which may occur during this kind of seizure include excessive saliva production, biting of the tongue or cheek, and loss of bladder or bowel control. Consciousness is regained slowly.
The postictal (post-seizure) symptoms may include headache, confusion, and fatigue lasting minutes to hours. Shortly after consciousness is regained the person will often fall asleep.
When tonic-clonic seizures last more than five minutes (not including the postictal phase) or the person has two or more in a row, medical attention should be obtained (see First Aid). When tonic-clonic seizures recur in a series of three or more seizures or last longer than 30 minutes the condition is known as Status Epilepticus. Status-epilepticus can be life-threatening. Immediate medical attention is necessary.
b) Absence Seizures (formerly called Petit Mal) consist of brief episodes of staring for a period of 5-30 seconds. Impairment of awareness begins without warning and ends suddenly, leaving the person alert and attentive. Usually associated with this seizure type are minor repetitive movements such as eye blinking. If the seizure lasts more than 10 seconds, brief mouth or hand movements may be seen.
A person may have 50 - 100 absence seizures a day. Without treatment, the seizures may interfere with learning. Absence seizures almost always begin in childhood (four to 14 years of age) and often resolve in late teenage years.
c) Myoclonic Seizures occur as brief, shock-like jerks of a muscle or group of muscles. Epileptic myoclonic seizures usually cause abnormal movements on both sides of the body at the same time. The neck, shoulders, upper arms, body and upper legs are usually involved. Movements resembling myoclonus may occur in healthy people who do not have epilepsy. For example, as many people fall asleep, their bodies suddenly jerk (referred to as “sleep starts” or “sleep jerks”).
d) Tonic Seizures usually last less than 20 seconds and are associated with sudden stiffening movements of the body, arms or legs, involving both sides of the body. They are most common during sleep.
e) Atonic Seizures usually begin in childhood (lasting for less than 15 seconds) and are associated with an abrupt loss of muscle tone that causes the eyelids to droop or the head to nod. The person may drop things or fall to the ground. Repeated injuries may occur as a result of this type of seizure.
Partial seizures begin with an abnormal burst of electrical activity in a restricted area of the brain. The signs and symptoms of a partial seizure depend on what part of the brain is involved during the seizure. Simple and complex partial seizures are the main types of partial seizures.
In this context, “simple” implies no loss of awareness. “Complex” means there is an impairment of consciousness. If a partial seizure spreads from a small part of the brain to involve both sides of the brain, it is called a partial seizure that becomes “secondarily generalized”. This seizure begins with subtle features but may become a tonic-clonic seizure when the abnormal electrical activity spreads to all of the brain.
a) Simple Partial Seizures leave the person alert and able to remember what happened afterward since consciousness is not impaired. A simple partial seizure may consist of nothing more than a strange sensation (tingling feeling in part of the body) or a rhythmic jerking of one limb, part of the limb, or the face. Any of the senses may be affected (touch, smell, taste, vision, and hearing). Simple partial seizures may last seconds to minutes and sometimes will precede a complex partial seizure or a secondarily generalized tonic-clonic seizure. Minor or vague symptoms may go unnoticed.
b) Complex Partial Seizures are the most common type of partial seizures in both children and adults. This seizure type is accompanied by impaired awareness and may be preceded by a simple partial seizure (the aura). The seizure may start with strange sensations such as fear, nausea, smell, taste, or deja vu, depending on where in the brain the seizure begins.
The person may look dazed and confused and make repetitive movements such as lip smacking, chewing, or hand and body movements. Sometimes the person may speak inappropriately or carry out semi-purposeful tasks. The person will not remember these events after the seizure.
A complex partial seizure may last from one to five minutes and may be followed by drowsiness or confusion. If the seizure spreads into other brain regions, a complex partial seizure may evolve to a generalized tonic-clonic seizure.
Researchers tell us that between 0.5 and 1% of the population suffers from epilepsy – an estimated 50 million people worldwide. Most epilepsy begins at the extremes of age (childhood and old age) but new cases can develop at any age (depending on the cause).
There are a number of resources a physician will use to determine the diagnosis of epilepsy. Medical history obtained from the patient is essential to the diagnosis. A careful description of the circumstances and events before, during and after the seizure provides critical clues in determining if the diagnosis is epilepsy. Reports from the patient and witnesses provide valuable information to the physician.
There are tests conducted which may help determine the diagnosis of epilepsy. Not all patients require all of these tests.
a) Electroencephalogram (EEG) is the most specific test for diagnosing epilepsy because it records electrical brain function (remember, epilepsy is a disorder of abnormal electrical function). By using small electrodes (flat metal disks) attached to the scalp with a sticky paste, the electrical activity produced by the brain is recorded. The test is painless and harmless and takes approximately one and a half hours from start to finish.
Sometimes the brain functions perfectly normally during an EEG. Therefore, patients with epilepsy do not necessarily always show an EEG abnormality with a single recording. The abnormal electrical discharges are more likely to be detected after multiple or prolonged recordings. Persons may sometimes be asked to stay awake all night before having an EEG because abnormal electrical activity may express itself during the EEG test after sleep deprivation. The EEG pattern recorded helps define the type of the seizures.
b) Video EEG Telemetry
A routine EEG (even with sleep deprivation) may not provide the information needed for diagnosis and treatment. It may be necessary to record the EEG during actual seizures. To undergo Video EEG Telemetry, a person must be admitted to hospital and be monitored, both by EEG and a video camera, twenty-four hours a day. Video EEG Telemetry is critical in the preoperative evaluation of persons being considered for epilepsy surgery.
c) Computerized Axial Topography (CT Scan) examines brain structure. During a CT Scan, a thin beam of X-rays is focused around the head. The X-ray tube moves around the site taking many pictures which are processed by a computer. A special “dye” may be injected to make the pictures clearer.
This test is performed to try and identify a cause for the epilepsy or seizures (stroke, tumor, etc).
d) Magnetic Resonance Imaging (MRI Scan) provides very precise and life-like pictures of brain structure, using a very large magnet, radio waves and computer. Like the CT scan, the MRI scan is also performed to try to find a cause for the diagnosis of epilepsy.
Memory problems and other cognitive difficulties are common in persons with seizures. The psychologist who performs the neuropsychological evaluation will assess your particular situation. This is done through an interview and some testing. The psychologist will ask about how epilepsy has affected your personal, social, academic, and vocational life. In addition, the psychologist will give you paper and pencil tests of memory, attention, thinking, reasoning motor skills, language, and spatial skills. The neuropsychological evaluation takes about five hours broken up into shorter sessions.
A neuropsychological evaluation can discover if speech functions are controlled by the left or right side of your brain. Secondly, the pattern of strengths and weaknesses you show on the test results tells the doctor what parts of the brain might be healthy or compromised. Thirdly, the neuropsychological evaluation can assist in the identification of epilepsy surgery candidates who might be at risk for serious memory or speech disorders.
f) Sodium-Amytal Testing
Prior to epilepsy surgery, a patient may undergo sodium-amytal testing in order to make sure that memory and speech functions are not located in the part of the brain that will be removed. The neuroradiologist injects a medication into the blood supply to the brain, putting half of the brain to sleep for approximately 10 minutes. During that time, the neuropsychologist questions the patient to reveal which functions are preserved in the “awake half” of the brain. The sodium-amytal test takes approximately one hour to complete.
Some types of epilepsy have an inherited pattern. Most commonly these are forms of the generalized epilepsies that begin in childhood or adolescence. Some people have certain inherited diseases (rare in occurrence) that have epilepsy as one feature of the illness. When epilepsy is the sole manifestation of the illness, there is a low probability of inheritance.
Antiepileptic drugs are the principal therapy for treating epilepsy. These drugs do not cure epilepsy but attempt to control it by suppressing seizures. The ultimate goal of antiepileptic drug therapy is to establish perfect seizure control and minimal or no side effects from medication. Sometimes long-term seizure control may not be possible because of the underlying cause.
Drug therapy must be individualized. It is important for the patient to be an active participant in the discussion and treatment of his or her epilepsy. Open communication between the physician and patient about what to expect, what is experienced, what is tolerable, and the impact of both adverse medication effects and seizures on the quality of life is the best way to manage drug therapy. The person’s lifestyle and cost of the drug are additional factors which the physician must take into consideration when recommending a particular medication for seizure control.
When drug treatment of epilepsy is started, it may take several months of adjusting dosages and trying different drugs before optimal effects can be achieved.
Antiepileptic drugs (AEDs) must be taken daily in order to maintain a steady level of drug in the bloodstream and brain to be effective in preventing seizures. Some drugs are more effective for certain types of seizures than others.
After a medication is swallowed it is absorbed into the blood and exerts its effect by eventually getting to the brain. Some drugs are broken down to other chemicals in the liver; some are excreted unchanged by the liver and kidney. The speed that this occurs varies from person to person, drug to drug, and by the presence of other medication. For these reasons, some medications may need to be taken more frequently in order to maintain a relatively constant level of medication in the bloodstream.
The level of some drugs in the blood may be measured in order to better adjust the dosage and study how the body absorbs and metabolizes a particular drug. When a medication is added or its dosage changed, it usually takes several days before the body establishes a new steady level of the drug.
Blood levels are not generally required once the patient has achieved optimal seizure control unless adverse side effects are evident. Some of the new medications do not require measurement of blood levels.
Here are some helpful tips on gaining the best possible seizure control:
Surgical therapy has been used for more than a century, but the past three decades have seen a dramatic rise in its use. Patients with partial epilepsy who have had minimal success with drug therapy for controlling seizures are usually candidates for a preoperative assessment for surgical therapy. The goal of surgery is to remove the region of the brain that triggers the seizures, without affecting vital functions such as language, memory, movements and sensation.
Surgery for epilepsy is usually done at highly specialized centres and requires a great deal of patient cooperation for the extensive pre-operative testing used to determine whether surgery would be of benefit. As with other surgical procedures, the benefits must always be carefully weighed against the risks.
Vagus Nerve Stimulation
Vagus Nerve Stimulation (VNS) is a surgical therapy that involves the implantation of a battery-powered device called a Vagus Nerve Stimulator under the skin in the chest. The device is similar to a heart pacemaker. A wire runs from the device to the vagus nerve in the neck. The VNS device stimulates the left vagus nerve which then sends an electrical signal to the brain. The signals help to prevent or interrupt the electrical disturbances in the brain that result in seizures.
A doctor programs the device to deliver periodic doses of stimulation, such as 30 seconds of stimulation followed by five minutes of no stimulation.
The individual or a caregiver can start or stop the stimulation by hand with the use of a special magnet. If a person experiences an aura or feels that a seizure is beginning, the magnet can be passed over the chest where the generator is located. This will activate extra stimulation to attempt to stop the seizure or reduce how long the seizure continues or its intensity.
Individuals using the device should ask the doctor how long the battery will last in order to allow for replacement when necessary. Replacement of the battery requires minor surgery.
VNS is not suitable for everyone with epilepsy. It is being used in patients who do not respond to medication and who are not suitable for epilepsy-related surgery.
The procedure has successfully reduced seizure frequency, intensity, and/or duration in some individuals when used with previous seizure medication.
There can be some adverse side effects including hoarseness, sore throat, shortness of breath, and coughing. Typically these side effects occur during stimulation. If the hoarseness is persistent or uncomfortable, the doctor should be notified.
A strict ketogenic diet high in fats and low in protein and carbo¬hydrates has been used in the treatment of difficult-to-control epilepsy in children. Occasionally it is used in the treatment of teenagers and adults. A chemical change is created in the body called ketosis resulting in the body breaking down fats instead of carbohydrates. This process inhibits seizures in some people.
The diet requires medical supervision. It does not provide all of the vitamins and minerals necessary for health so nutritional supplements are required to avoid deficiencies. Use of these supplements must be monitored by a doctor. Studies indicate that approximately one-third of children strictly adhering to the diet are seizure free or close to it, one-third experience a reduction in seizures, and one-third are unresponsive.
There are many complementary therapies that some individuals have found helpful in seizure control. Although some of these methods may not have been scientifically proven, there are people with epilepsy who have found that they help in reducing seizures. A number of the methods were developed centuries ago before current treatments were available.
It is important to remember that all therapies should be discussed with a doctor. Complementary therapies are used to supplement and not to replace accepted treatments.
Advocates of a self-control approach in dealing with epilepsy believe that playing an active role will not only alleviate feelings of powerlessness but may also be effective in controlling seizures. Through persistence and careful observation, some individuals have developed the ability to use tools such as mental imagery, odors, or relaxation techniques to prevent or delay seizures.
Some individuals have found that yoga, massage therapy, or meditation is helpful.
Others advocate aromatherapy, herbal remedies, or vitamin therapy, while a number have had positive results from art, music, and pet therapy. Individuals have also found that techniques such as acupuncture and hypnosis are effective in seizure control.
Reflexology is a technique involving the application of pressure to points on the foot or hand that are believed to correspond to different parts of the body. For example, by massaging a certain part of the foot, a reflexologist tries to bring about a response in a part of the body. People have sometimes found this approach helpful.
Biofeedback uses EEG recordings to help a patient develop a level of brain activity believed to raise the seizure threshold. Supporters of this approach believe that one can learn to control brain waves and that once a successful approach has been learned, the person may eventually be able to exert control without the assistance of the EEG recordings.
Many people with epilepsy complain of absentmindedness, forgetting names and things that went on in the past. This may be due to the underlying cause of the epilepsy, medication, or a combination of both. While there is no cure, there are ways to compensate for these difficulties.
First, try to be organized about what you want to remember. Keep a daily diary where you record important events. Write down when seizures occur, when medications are changed, when you have appointments, and even the names of new people you want to remember. Make the diary a big part of your life, checking it often (e.g. every morning) and writing in it every day.
Secondly, when you want to remember to do something, use a simple aid. For example, if your aunt’s birthday is next week, mark her name on that day in a calendar or diary. Put another note to yourself on the telephone, if you plan to call her that day. The notes and cues will prompt your memory.
When you want to remember a phone message, write down the important points in a diary or book (not on loose sheets of paper). Then place a colourful clip on the top of that page to remind you to pass on the message to your friend.
If you cannot remember a name or number you knew before, stay calm. Becoming upset only makes it harder to remember. Accept the fact that your memory is not perfect, and you need extra time to recall. When did you last see them? Who were they with? What were you doing? Often these clues gradually build up the memory trace, and make it easier to recall the name.
Finally, your memory will be better if you pay attention to one thing at a time. When you want to remember something you are reading, find a quiet spot with no interruptions. Concentrate on the material and ignore distracting thoughts or noises. Turn off the TV and radio if you have to study for a test. Learning means rehearsing the material several times. Discovering humorous or meaningful associations with the material makes a stronger memory trace.
Depending on the seizure type and frequency, certain restrictions may apply. Each case must be judged individually. Consult your physician to determine what restrictions may apply to you. It is your responsibility to be straight-forward, honest, and apply common sense in any discussion regarding restrictions on activities such as driving, working at heights, or bathing and swimming alone.
Generalized Tonic Clonic Seizure
In convulsive (tonic-clonic or grand mal) seizures, the individual loses consciousness and falls. The body is initially rigid (tonic phase). In the clonic phase, the arms and legs jerk or twitch rhythmically. Consciousness is regained slowly.
Complex Partial Seizure
For someone with disturbance of consciousness and undirected behaviour, such as mumbling or random movements including head turning or pulling at clothes:
Please note, the seizure and post seizure confusion may last as long as 20 minutes.
Absence Seizure (Petit Mal)
For momentary lapses of attention (absence or petit mal seizures) no first aid is needed; the seizures only last a few seconds. The individual may appear to be daydreaming. Because these seizures are so mild looking, they may go undiagnosed. If you suspect someone of having absence seizures, bring it to the attention of an appropriate person.
Our thanks to Deirdre Floyd, President, Epilepsy Association of Nova Scotia and staff of the Epilepsy Program (Halifax Infirmary Site), Ottawa General Hospital Epilepsy Clinic and Capital Health, Nova Scotia for preparing the above information.
Our thanks to the Edmonton Epilepsy Association for providing the content found in the "What is epilepsy?" and "Addtional Treatment Options" sections.
Our thanks to Dr. Orrin Devinsky for writing the “Introduction to Epilepsy Research” as well as ensuring accuracy of information.