What is a Seizure?
A seizure is a sudden surge of electrical activity in the brain that usually affects how a person feels or acts for a short time. Seizures are not a disease in themselves. Instead, they are a symptom of many different disorders that can affect the brain. Some seizures can hardly be noticed, while others are totally disabling.
The seizures in epilepsy may be related to a brain injury or a family tendency, but often the cause is completely unknown. The word "epilepsy" does not indicate anything about the cause or severity of the person's seizures.
About half of the people who have one seizure without a clear cause will have another one, usually within 6 months. You are twice as likely to have another seizure if you have a known brain injury or other type of brain abnormality. If you do have two seizures, there's about an 80% chance that you'll have more.
If your first seizure occurred at the time of an injury or infection in the brain, you are more likely to develop epilepsy than if you had not had a seizure in that situation.
More seizures are also likely if your doctor finds abnormalities on a neurological examination; a set of tests of the functioning of your nervous system that is performed in the doctor's office.
Another thing that can help your doctor predict whether you will have more seizures is an EEG, electroencephalogram (e-LEK-tro-en-SEF-uh-LOG-ram), a test in which wires attached to your scalp record your brain waves. Certain patterns on the EEG are typical of epilepsy. If your brain waves show patterns of that type, you are about twice as likely to develop epilepsy as someone who does not have those patterns.
Symptoms of a Seizure
A seizure is usually defined as a sudden alteration of behavior due to a temporary change in the electrical functioning of the brain, in particular the outside rim of the brain called the cortex. Below you will find some of the symptoms people with epilepsy may experience before, during and after a seizure. Seizures can take on many different forms and seizures affect different people in different ways. It is not implied that every person with seizures will experience every symptom described below.
Seizures have a beginning, middle, and end.
When an individual is aware of the beginning, it may be thought of as a warning or aura. On the other hand, an individual may not be aware of the beginning and therefore have no warning.
Sometimes, the warning or aura is not followed by any other symptoms. It may be considered a simple partial seizure by the doctor.
The middle of the seizure may take several different forms. For people who have warnings, the aura may simply continue or it may turn into a complex partial seizure or a convulsion. For those who do not have a warning, the seizure may continue as a complex partial seizure or it may evolve into a convulsion.
The end to a seizure represents a transition from the seizure back to the individual’s normal state. This period is referred to as the “post-ictal period” (an ictus is a seizure) and signifies the recovery period for the brain. It may last from seconds to minutes to hours, depending on several factors including which part(s) of the brain were affected by the seizure and whether the individual was on anti-seizure medication. If a person has a complex partial seizure or a convulsion, their level of awareness gradually improves during the post-ictal period, much like a person waking up from anesthesia after an operation. There are other symptoms that occur during the post-ictal period and are detailed below.
Please note: Below is only a partial list, some people may experience other symptoms not listed below. These lists are meant to help patients communicate with their physicians.
Early seizure symptoms (warnings):
Visual loss or blurring
Sometimes seizures come with no warning
Electric Shock Feeling
Loss of consciousness
Out of body experience
Visual loss or blurring
Eyes rolling up
Inability to move
After-seizure symptoms (post-ictal):
Depression and sadness
Urge to urinate/defecate
Experiencing or witnessing a seizure can be scary and embarrassing, it is important to reassure and support the person affected and ensure that they are safe and comfortable.
Types of Seizure
Seizures take many forms. Before your doctor can prescribe the right treatment, he or she must figure out which type (or types) you have.
There are so many kinds of seizures that neurologists who specialize in epilepsy are still updating their thinking about how to classify them. Usually, they classify seizures into two types, primary generalized seizures and partial seizures. The difference between these types is in how they begin:
Primary generalized seizures:
Primary generalized seizures begin with a widespread electrical discharge that involves both sides of the brain at once. Hereditary factors are important in many of these seizures.
Partial seizures begin with an electrical discharge in one limited area of the brain. Some are related to head injury, brain infection, stroke, or tumor, but in most cases the cause is unknown.
One question that is used to further classify partial seizures is whether consciousness (the ability to respond and remember) is "impaired" or "preserved." The difference may seem obvious, but really there are many degrees of impairment or preservation of consciousness.
Identifying certain seizure types and other characteristics of a person's epilepsy like the age at which it begins, for instance, allows doctors to classify some cases into epilepsy syndromes. This kind of classification helps us to know how long the epilepsy will last and the best way to treat it.
Primary Generalized Seizures:
Absence seizures are brief episodes of staring. (Although the name looks like a regular English word, your neurologist may pronounce it ab-SAWNTZ.) Another name for them is petit mal (PET-ee mahl). During the seizure, awareness and responsiveness are impaired. People who have them usually don't realize when they've had one. There is no warning before a seizure, and the person is completely alert immediately afterward.
Simple absence seizures are just stares. Many absence seizures are considered complex absence seizures, which means that they include a change in muscle activity. The most common movements are eye blinks. Other movements include slight tasting movements of the mouth, hand movements such as rubbing the fingers together, and contraction or relaxation of the muscles. Complex absence seizures are often more than 10 seconds long.
Atypical absence seizures - Atypical (a-TIP-i-kul) means unusual or not typical. The person will stare (as they would in any absence seizure) but often is somewhat responsive. Eye blinking or slight jerking movements of the lips may occur. This behavior can be hard to distinguish from the person's usual behavior, especially in those with cognitive impairment.
Myoclonic seizures - Myoclonic (MY-o-KLON-ik) seizures are brief, shock-like jerks of a muscle or a group of muscles. "Myo" means muscle and "clonus" (KLOH-nus) means rapidly alternating contraction and relaxation—jerking or twitching—of a muscle.
Even people without epilepsy can experience myoclonus in hiccups or in a sudden jerk that may wake you up as you're just falling asleep. These things are normal.
In epilepsy, myoclonic seizures usually cause abnormal movements on both sides of the body at the same time. They occur in a variety of epilepsy syndromes that have different characteristics:
Juvenile myoclonic epilepsy: The seizures usually involve the neck, shoulders, and upper arms. In many patients the seizures most often occur soon after waking up. They usually begin around puberty or sometimes in early adulthood in people with a normal range of intelligence. In most cases, these seizures can be well controlled with medication but it must be continued throughout life.
Lennox-Gastaut syndrome: This is an uncommon syndrome that usually includes other types of seizures as well. It begins in early childhood. The myoclonic seizures usually involve the neck, shoulders, upper arms, and often the face. They may be quite strong and are difficult to control.
Progressive myoclonic epilepsy: The rare syndromes in this category feature a combination of myoclonic seizures and tonic-clonic seizures. Treatment is usually not successful for very long, as the patient deteriorates over time.
Atonic seizures - Muscle "tone" is the muscle's normal tension. "Atonic" (a-TON-ik) means "without tone," so in an atonic seizure, muscles suddenly lose strength. The eyelids may droop, the head may nod, and the person may drop things and often falls to the ground. These seizures are also called "drop attacks" or "drop seizures." The person usually remains conscious.
Another name for this type of seizure is "akinetic" (a-kin-ET-ik), which means "without movement."
Tonic seizures - Muscle "tone" is the muscle's normal tension at rest. In a "tonic" seizure, the tone is greatly increased and the body, arms, or legs make sudden stiffening movements. Consciousness is usually preserved. Tonic seizures most often occur during sleep and usually involve all or most of the brain, affecting both sides of the body. If the person is standing when the seizure starts, he or she often will fall.
Clonic seizures - "Clonus" (KLOH-nus) means rapidly alternating contraction and relaxation of a muscle -- in other words, repeated jerking. The movements cannot be stopped by restraining or repositioning the arms or legs. Clonic (KLON-ik) seizures are rare, however. Much more common are tonic-clonic seizures, in which the jerking is preceded by stiffening (the "tonic" part). Sometimes tonic-clonic seizures start with jerking alone. These are called clonic-tonic-clonic seizures.
Tonic-clonic seizures - This type is what most people think of when they hear the word "seizure." An older term for them is "grand mal." As implied by the name, they combine the characteristics of tonic seizures and clonic seizures. The tonic phase comes first: All the muscles stiffen. Air being forced past the vocal cords may cause a cry or groan. The person loses consciousness and falls to the floor. The tongue or cheek may be bitten, so bloody saliva may sometimes come from the mouth. The person may turn a bit blue in the face. After the tonic phase comes the clonic phase: The arms and usually the legs begin to jerk rapidly and rhythmically, bending and relaxing at the elbows, hips, and knees. After a few minutes, the jerking slows and stops. Bladder or bowel control sometimes is lost as the body relaxes. Consciousness returns slowly, and the person may be drowsy, confused, agitated, or depressed.
Partial Seizures (also called Focal Seizures):
Simple partial seizures
Doctors often divide simple partial seizures into categories depending on the type of symptoms the person experiences:
Motor seizures - These cause a change in muscle activity. For example, a person may have abnormal movements such as jerking of a finger or stiffening of part of the body. These movements may spread, either staying on one side of the body (opposite the affected area of the brain) or extending to both sides. Other examples are weakness, which can even affect speech, and coordinated actions such as laughter or automatic hand movements. The person may or may not be aware of these movements.
Sensory seizures - These cause changes in any one of the senses. People with sensory seizures may smell or taste things that aren't there; hear clicking, ringing, or a person's voice when there is no actual sound; or feel a sensation of "pins and needles" or numbness. Seizures may even be painful for some patients. They may feel as if they are floating or spinning in space. They may have visual hallucinations, seeing things that aren't there (a spot of light, a scene with people). They also may experience illusions—distortions of true sensations. For instance, they may believe that a parked car is moving farther away, or that a person's voice is muffled when it's actually clear.
Autonomic seizures - These cause changes in the part of the nervous system that automatically controls bodily functions. These common seizures may include strange or unpleasant sensations in the stomach, chest, or head; changes in the heart rate or breathing; sweating; or goose bumps.
Psychic seizures - These change how people think, feel, or experience things. They may have problems with memory, garbled speech, an inability to find the right word, or trouble understanding spoken or written language. They may suddenly feel emotions like fear, depression, or happiness with no outside reason. Some may feel as though they are outside their body or may have feelings of déja vu ("I've been through this before") or jamais vu ("This is new to me"— even though the setting is really familiar).
Complex partial seizures
These usually start in a small area of the temporal lobe or frontal lobe of the brain. They quickly involve other areas of the brain that affect alertness and awareness. So even though the person's eyes are open and they may make movements that seem to have a purpose, in reality "nobody's home." If the symptoms are subtle, other people may think the person is just daydreaming.
Some people can have seizures of this kind without realizing that anything has happened. Because the seizure can wipe out memories of events just before or after it, however, memory lapses can be a problem.
Some of these seizures (usually ones beginning in the temporal lobe) start with a simple partial seizure. Also called an aura, this warning seizure often includes an odd feeling in the stomach. Then the person loses awareness and stares blankly. Most people move their mouth, pick at the air or their clothing, or perform other purposeless actions. These movements are called "automatisms" (aw-TOM-ah-TIZ-ums). Less often, people may repeat words or phrases, laugh, scream, or cry. Some people do things during these seizures that can be dangerous or embarrassing, such as walking into traffic or taking their clothes off. These people need to take precautions in advance.
Complex partial seizures starting in the frontal lobe tend to be shorter than the ones from the temporal lobe. The seizures that start in the frontal lobe are also more likely to include automatisms like bicycling movements of the legs or pelvic thrusting.
Some complex partial seizures turn into secondarily generalized seizures.
Secondarily generalized seizures - These seizures are called "secondarily generalized" because they only become generalized (spread to both sides of the brain) after the initial or "primary" event, a partial seizure, has already begun. They happen when a burst of electrical activity in a limited area (the partial seizure) spreads throughout the brain. Sometimes the person does not recall the first part of the seizure. These seizures occur in more than 30% of people with partial epilepsy.
Seizures of this kind start as a partial seizure — that is, they start in one limited area of the brain. The forms they take vary as much as other partial seizures. But then (sometimes so quickly that the partial seizure is hardly noticed) the seizure spreads throughout the brain, becoming "generalized."
Some people have a distinctive feeling or some other warning sign when a seizure is coming. A warning like this is also called an aura. Although some auras are unpleasant, they can be helpful because they can give you time to prepare for the seizure and keep yourself from being injured. Most injuries from seizures happen if there is no warning sign, if the warning is not recognized, or if there is not enough time to react to it.
Auras vary significantly between different people. Yours may happen right before a seizure or several minutes to hours earlier. Common warning signs right before seizures are changes in bodily sensations, changes in your ability to interact with things happening outside you, and changes in how familiar the outside world seems to you. Other warning signs that may happen hours before a seizure are depression, irritability, sleep disruption, nausea, and headache.
People with complex partial seizures are the most likely to experience warning signs. Approximately 55% to 65% of people with these seizures experience some type of aura. It is unclear whether having seizures that arise from one particular side of the brain makes you more likely to have auras than people whose seizures arise on the other side.
What have we learned about auras?
Researchers who have studied different types of auras for many years have found patterns. For many people, the sensations in an aura occur in the same order. For example, you may always feel fear, then déjà vu (the feeling that you've been there before), then a strange taste in your mouth. This pattern would point towards the existence of a prominent seizure pathway in your brain.
The part of your brain where your seizures originate (your seizure focus) also may be linked to a specific type of aura because an aura represents the beginning of a seizure. Since different parts of the brain are responsible for different things, the warning signs you experience will be related to the functions of the section of brain where the seizure is about to occur. People whose seizures begin in the temporal lobe tend to have certain types of auras and those whose seizures begin somewhere else often will have different types.
Does my aura mean I have an especially severe form of epilepsy?
Studies have shown that no specific aura is linked with a poor or negative outcome. Some researchers have found that fear during a seizure (ictal fear) is associated with increased psychological and behavioral disturbance, but the reasons for this are unclear.
What should I do if I have auras before my seizures?
Take advantage of the opportunity to look for a safe place to experience the seizure that is likely to follow. Telling other people about your warning signs will make it easier for them to help you and also can help them to understand epilepsy. You may be able to say, "I'm not feeling well" or "I'm going to have a seizure." Or you may just do something that other people or even animals, such as some dogs can recognize: You may suddenly get a strange expression on your face. You may stop talking in the middle of a sentence. If you are listening to someone else, you may seem to drift off and not pay attention. Your whole body may tense up. Family members and friends who recognize the meaning of these signs can help you stay safe during your seizure.
Should I tell my doctor about my auras, even if they are embarrassing or weird?
Absolutely. Auras aren't something you are able to control-they are caused by some small part of your brain that is misfiring. As strange as your aura may be, your doctor will be understanding.
It's important to tell your doctor about your auras so that your diagnosis will be more accurate and your treatment will be more focused. Knowing what type of auras you have can help your doctor find where your seizures begin. Although auras alone are rarely used to make a diagnosis, they can be used to confirm one.
Tell your doctor if you experience any warning signs on a regular basis, no matter how often they happen. If you experience a familiar sign that is not followed by any other seizure activity, make a note of it and tell your doctor about it anyway. You may be having small seizures, or another related condition that has been untreated. It's a good idea to keep track of your auras and seizures on a calendar so your report to the doctor will be accurate.