The list below outlines the general definitions of some commonly found seizure types. It is helpful to learn the names and the terms used to describe these seizures so that you can describe your disorder directly and accurately to other people and to your health care providers.
In an absence seizure, epileptic activity occurs throughout the entire brain. It is a milder type of activity which causes unconsciousness without causing convulsions. After the seizure, there is no memory of it.
An absence seizure begins abruptly and without warning, consists of a period of unconsciousness with a blank stare, and ends abruptly. There is no confusion after the seizure, and the person can usually resume full activity immediately. An absence seizure may be accompanied by chewing movements, rapid breathing, or rhythmic blinking.
Absence seizures are short, usually lasting only 2-10 seconds. They are very mild, and may go unnoticed by parents and teachers. Because absence seizures may recur frequently during the day, a child who experiences them may have difficulty learning if they are not recognized and treated.
Atonic seizures (drop attacks) are not seen in many children. Without warning, a child abruptly loses consciousness, collapses and falls to the floor. There is no convulsion, but children may bang their heads as they fall. Recovery occurs after a few seconds. The child regains consciousness, and can again stand and walk.
Atonic seizures may occur with Lennox-Gastaut Syndrome. They sometimes resist anticonvulsant medication. If so, the child may have to wear a helmet to prevent head injuries.
Catamenial refers to seizure activity associated with a woman’s menstrual cycle. For more than one hundred years, the relationship between seizures and menstruation has been examined. Studies have shown that fluctuations in female hormones prior to and during menstruation may elevate seizure frequency in some women. In a small percentage of women, catamenial seizures may occur only during the days just before their periods; for others, during the period itself. Higher ratios of estrogen to progesterone may increase seizure frequency. Water retention, electrolyte imbalance, and even poor sleep are also contributing causes.
The connection between menstruation and seizures has been demonstrated in women with simple partial, complex partial, and generalized tonic-clonic seizures. However, different types of seizures may be associated with different phases of a woman’s menstrual cycle. For example, a women with absence seizures may have more seizures during days 16 to 28 of her average cycle and may have the least during her period. A women with partial seizures, on the other hand, tends to have fewer seizures during days 16 to 28 and more just prior to ovulation and during menstruation.
Menstrual disorders, such as amenorrhea (the absence of menstruation), oligomenorrhea (a scanty menstruation), cycles of irregular length and an absence of changes in cervical mucus have been reported in women with epilepsy, especially those who experience complex partial seizures.
Mood swings, often pronounced prior to and during menstruation, may be further aggravated by anticonvulsant medication. If mood swings become problematic, it is recommended you discuss adjustments to medication with your physician and/or neurologist.
During a clonic seizure, you may lose control of bodily functions and begin jerking in various parts of the body. Consciousness may be temporarily lost and followed by confusion. Clonic seizures begin in early childhood. They often appear to be a case of massive bilateral epileptic myoclonus, though the motor features of it may be less symmetrical. With time, clonic seizures may eventually progress to generalized tonic-clonic seizures.
A complex partial seizure occurs when epileptic activity spreads to both temporal lobes in the brain. A complex partial seizure often occurs after a simple partial seizure of temporal lobe origin.
A complex partial seizure does not involve convulsions, but consciousness is impaired. Someone experiencing one will no longer respond to questions after the seizure starts. A complex partial seizure often begins with a blank look or empty stare. They will appear unaware of their surroundings and may seem dazed. The seizure may progress to include chewing movements, uncoordinated activity, or sometimes performing meaningless bits of behaviour which appear random and clumsy. These automatisms may include actions such as picking at their clothes, trying to remove them, walking about aimlessly, picking up things, or mumbling. Someone experiencing a complex partial seizure may become frightened and try to run and struggle. Following the seizure, there will be no memory of it.
A complex partial seizure usually lasts about 2 to 4 minutes. It may be followed by a state of confusion lasting longer. Once the pattern of seizures is established, it will usually be repeated with each subsequent seizure.
Complex partial seizures sometimes resist anti-convulsant medication.
A febrile seizure occurs when a child has a high fever, most commonly above 38.3°C (101°F), and usually on the first day of a rapid rise in body temperature. A febrile seizure is usually seen in children between 6 months and 3 years of age, although they can occur in children to 5 years of age.
There are 2 types of febrile seizures: simple and complex.
Simple febrile seizures are more common and relatively harmless. They usually last less than 15 minutes and have no after-effects. A neurological examination following a simple seizure will yield no abnormalities.
Complex febrile seizures may be more threatening: they can occur at body temperatures lower than 38.3°C and can last longer than 15 minutes. Only 1 side of the body is affected during a complex febrile seizure and neurological reports may indicate abnormalities.
In both cases, febrile seizures pose no threat of mental retardation, cerebral palsy, learning disabilities, or death. The incidence of febrile seizures does not indicate a possibility of developing epilepsy: less than 2% of children who experience febrile seizures will develop an epilepsy later in life. Febrile seizures are classed as incidents rather than as a condition.
Overall, the incidence of febrile seizures is higher in males than in females.
There are a number of possible causes of febrile seizures. A fundamental cause for all febrile seizures is a vulnerability of the brain to an oncoming seizure. Children have a higher susceptibility to seizure activity in the brain — a lower seizure threshold — because of their age and the immaturity of their body’s immune system. Complicated by a rapidly rising fever and possibly the general condition of health, a febrile seizure may occur. Several other factors may increase the risk of seizure: a family history of seizures, chronic maternal ill health, parental fertility problems, breech birth, Caesarean birth, small birth weight, developmental delay, and cerebral problems may increase the incidence of febrile seizures. Smoking and drug intake (including anti-epileptic drugs) during pregnancy can further increase the risk.
Febrile seizures will be experienced by only 3-4% of children and only with a fever. With no family history of seizures, chances are very low for your child to have a febrile seizure. Certain precautions, including the use of medication, will reduce this chance.
Reducing the child’s body temperature will lower the seizure risk. [To do this, cover the child’s exposed body with wet (not ice cold) cloths: evaporating water lowers temperature. Fanning will speed up the cooling process. After drying the child’s body, an analgesic is often prescribed to help stabilize the child’s body temperature. Such drugs should be kept to the minimum prescribed by your physician.]
Medications specific to febrile seizures, such as phenobarbital, offer another option. Phenobarbital is the most effective medication to prevent febrile seizures. Remember that it takes several days to accumulate an effective level of the drug in the blood and in the brain. Taking phenobarbital daily to maintain a specific amount in the blood may reduce the occurrence of febrile seizures. Because phenobarbital may cause hyperactivity, behavioral problems, sleep disturbances, hindered development of intelligence, and learning disabilities, it is usually prescribed only after many febrile seizures have occurred.
Although a seizure can be terrifying to a parent, stay calm and try to accurately assess the situation. A febrile seizure is usually mild and brief, often manifesting no more than a slight slumping and loss of consciousness, or a rolling of the eyes back in the head. Sometimes there may be convulsive stiffening and jerking, but there is no need to panic.
Protect the child from sharp, hot, or otherwise dangerous objects. Loosen tight clothing. Do not put anything in the child’s mouth. Do not restrict his/her movements. Roll the child on his/her side and try to keep everyone relaxed.
A febrile seizure produces no lasting effects. Only 25-30% of children who experience one will ever have another. Only when a seizure occurs within the child’s first year AND there is a family history of febrile seizures or epilepsy AND if it was a complex seizure will the chances of another incident increase to 80% or above. Otherwise, the chances of another incident are reduced to as low as 10%. Febrile seizures are rare; recurrence even rarer.
Febrile seizures have no lasting effects and children outgrow them after 5 years of age. Febrile seizures do not indicate the development of epilepsy.
Gelastic seizures are brief outbursts of emotion, usually in the form of a laugh or a cry. They may be accompanied by forced eye movements, chewing or grinding the teeth, tonic posturing, and clonic jerking. The person may appear confused and/or dazed during and after an episode. Gelastic seizures usually last 5 to 60 seconds. The person may remember them clearly or may be completely unaware of what occurred.
Gelastic seizures are both unpredictable and unprovoked by the person’s surroundings. They are abrupt in onset and quickly over. Gelastic seizures may occur nocturnally, waking the person from sleep and leaving them exhausted.
Research shows that gelastic seizures often occur in people who have an (often maternal) family history of migraines.
Infantile spasms are very rare. They occur only during the first year of life, usually starting around 3-7 months of age.
Infantile spasms consist of clusters of sudden, quick movements. Typically, if the child is sitting up, the head may fall forward, the arms will flex forward, and the body may flex at the waist. If lying down, the knees will be drawn up, with arms and head flexed forward as if the body is reaching for support.
Individual spasms last only 1 or 2 seconds. They often repeat in a series of 5 to 50 or more. A child may have many series per day. Spasms are most likely to occur when the child is drowsy, just waking from a nap or falling asleep.
Infantile spasms may occur as part of West syndrome. They sometimes resist anti-convulsant medication.
Musicogenic seizures are a reflex epilepsy triggered by certain types of music or even specific frequencies of pitch for which the person’s brain has a low threshold or tolerance. These sounds trigger focal epileptiform EEG discharges in cerebral areas specific to the triggering stimulus. This usually results in a complex partial seizure, but may also induce others, such as tonic-clonic seizures.
Musicogenic seizures usually involve a degree of cognitive or emotional appreciation of the stimulus. In some cases, merely thinking of the atmosphere and the emotions associated with a certain stimulus is enough to induce a seizure. They may also occur during sleep.
Carbamazepine and phenytoin may be prescribed to control this condition. Behavioral conditioning offers other possibilities and have yielded positive results. [In behavioral treatment, the patient is exposed repeatedly to a similar piece of music or even to the same piece altered sufficiently to not provoke a seizure. Eventually, the original stimulus may be heard with no ill effect.] Behavioural treatment may be time-consuming and may need to be reinforced later to maintain desensitization. In spite of this, behavioural conditioning may prove effective in the treatment of people who do not want to avoid the triggering stimulus or take medication.
Myoclonic seizures occur in several different types of childhood epilepsy. They involve abrupt muscle jerks in part or all the body. A hand may suddenly fling out, a shoulder may shrug, a foot may kick, or the entire body may jerk.
Myoclonic seizures can occur as a single event or in series. Consciousness and memory are not impaired. A myoclonic seizure may cause a child to spill or drop what s/he is holding or to fall from his/her chair.
Myoclonic seizures should not be confused with tics or "startle" responses.
Neonatal seizures occur in babies soon after birth. As many as 1.5 to 2.5% of newborns have seizures in the first month of life. A further 20% of all seizures in children under 3 years of age are neonatal seizures.
Neonatal disorders are generally classified as subtle, clonic, tonic, and myoclonic.
Subtle attacks are characterized by apneas with cyanosis or hypertonia, episodes of pallor, fixed staring, conjugate eye deviation, finger movements, paroxysmal eye blinking, nystagmus, vasomotor changes, episodic chewing movements, or stereotypic limb movements such as swimming or bicycling motions. Drooling and unusual alertness may accompany neonatal seizures. While these abnormal behavioral patterns in infants correspond to their seizure types, not all such clinical events are consistently related to EEG discharges and thus are not all epileptic in origin.
Neonatal seizures may be caused by various metabolic problems, brain damage, or a lack of oxygen during the prenatal period. Cerebral dysmorphism, prenatal infection and vascular occlusion, maternal drug abuse, and a family history of epilepsy can complicate the newborn’s health and may increase the risk of seizures. Furthermore, the seizures themselves may impede brain growth, resulting in cerebral palsy, mental retardation, or epilepsy at a later time.
Nocturnal seizures are usually tonic-clonic. They might occur just after a person has fallen asleep, just before waking, during daytime sleep, or while in a state of drowsiness. People who experience nocturnal seizures may find it difficult to wake up or to stay awake. Although unaware of having had a seizure while asleep, they may arise with a headache, have temper tantrums, or other destructive behavior throughout the day.
Nocturnal seizures are very uncommon and their mechanisms poorly understood. The majority of people with nocturnal seizures have idiopathic epilepsy and there is evidence that sleep enhances epileptic discharges in the EEG, though their daytime recordings may appear to be normal. However, if a pattern of limiting seizures to the hours of slumber is maintained, the chance of them occurring during the daytime is greatly reduced.
Psychogenic seizures are not classified as a form of epilepsy. They affect between 5 and 20 percent of people thought to have epilepsy. Psychogenic seizures can occur at any age, but are more common in people under the age of 55. They occur 3 times more frequently in women than men. They may arise from various psychological factors, may be prompted by stress, and may occur in response to suggestion. It has also been found that such disorders may be self-induced. They may be used to get attention, to be excused from work, to collect financial compensation, or merely to escape an intolerable social situation. They seldom occur in the absence of others. Trauma related to physical illness has been found to trigger these seizures in elderly individuals. People with early-onset psychogenic seizures often have a history of sexual abuse.
Psychogenic seizures can be characterized by features common with epilepsy like writhing and thrashing movements, quivering, screaming or talking sounds, and falling to the floor. Psychogenic attacks differ from epileptic seizures in that out-of-phase movements of the upper and lower extremities, pelvic thrusting, and side-to-side head movements are evident. However, psychogenic seizures vary from one occurrence to another and are not readily stereotyped. Indicators like pupillary dilation, depressed corneal reflexes, the presence of Babinski responses, autonomic cardiorespiratory changes, tongue biting and urinary/fecal incontinence are more probable with epilepsy and are not usually manifested in psychogenic seizures.
Psychogenic seizures may last a couple of minutes or hours, ending as abruptly as they began. Anxiety may be experienced prior to an attack, followed by relief and relaxation afterwards, leading some to postulate that psychogenic seizures may occur as a direct response to stress in order to relieve tension. Afterwards, patients usually have a vague recollection of the seizure, without the usual postictal symptoms of drowsiness and depression.
It is difficult to differentiate between psychogenic and epileptic seizures. However, one highly reliable indicator of a psychogenic seizure is eye closure during the seizure; when people with epilepsy have seizures the eyes tend to remain open. Still, statistics indicate that, in 20-30% of cases, epileptologists are incorrect in attempting to distinguish one from the other. Although psychogenic seizures are not caused by electrical discharges in the brain and thus do not register any EEG abnormalities, they are often mistaken for epileptic disorders. It is also possible to have both psychogenic seizures and epilepsy. Most patients with psychogenic seizures are misdiagnosed and consequently treated with epilepsy drugs or other epilepsy therapies, sometimes with severe and fatal side effects.
A seizure is considered a reflex seizure when it occurs as a direct response to a particular stimulus or event.
These seizures are experienced by approximately 6% of people with epilepsy. They can be triggered by visual stimulation, a sudden “startle”, or a variety of other factors alone or in combination.
If a patient only has seizures as a result of a certain stimulus then it is possible to control them by avoidance rather than through pharmalogical means.
Benign rolandic epilepsy is so named because the focus of repetitive spike activity in the brain is predominantly within the mid-temporal or parietal areas, near the motor or rolandic strip.
Seizures usually occur infrequently, as generalized nocturnal seizures characterized by a variety of minor tonic-clonic movements, often affecting only one side of the face. A seizure begins with a sensation starting at the corner of the mouth, followed by jerking of that corner. The jerking may then spread to the rest of that side of the face, in turn causing a twisting motion. Excessive salivation occurs, along with possible speech arrest. The child usually does not lose consciousness, except in cases of secondarily generalized seizures of this type. In rare cases, the seizure may progress to encompass the entire side of the body, becoming a generalized tonic-clonic condition.
Onset is usually after three years of age. One quarter of school-age children with epilepsy may have rolandic seizures. The condition is benign and is frequently outgrown by adolescence.
Secondarily generalized seizures are usually partial seizures evolving into generalized seizures, most often with tonic-clonic convulsions. The partial seizures which were once limited to one hemisphere of the brain progress to encompass the entire brain bilaterally, causing a generalized seizure. The clinical nature of a secondarily generalized seizure usually does not differ from that of the initial, originating seizure.
Secondarily generalized seizures are predominant in 16% of all children and 9% of all adults with seizure disorders. Most people with complex partial seizures and many with simple partial seizures will experience a secondarily generalized seizure at some point. When they occur frequently, the chances for future partial seizures may be increased. Secondarily generalized seizures occur infrequently and are easily controlled by anti-epileptic medication.
Simple partial seizures result from epileptic activity which is localized in one part of the brain, usually the cortex or limbic system.
Consciousness is not impaired: people experiencing a simple partial seizure can talk and answer questions. They will remember what went on during the seizure.
Simple partial seizures take different forms in different people. They are further classified according to their symptoms:
- Autonomic Seizures These seizures are accompanied by autonomic symptoms or signs, such as abdominal discomfort or nausea which may rise into the throat (epigastric rising), stomach pain, the rumbling sounds of gas moving in the intestines (borborygmi), belching, flatulence and vomiting. This has sometimes been referred to as abdominal epilepsy. Other symptoms may include pallor, flushing, sweating, hair standing on end (piloerection), dilation of the pupils, alterations in heart rate and respiration, and urination. A few people may experience sexual arousal, penile erection, and orgasm.
- Emotional and Other Simple partial seizures which arise in or near the temporal lobes often take the form of an odd experience. One may see or hear things that are not there. One feels emotions, often fear, but sometimes sadness, anger, or joy. There may be a bad smell or a bad taste, a funny feeling in the pit of the stomach or a choking sensation. These seizures are sometimes called simple partial seizures of temporal lobe origin or temporal lobe auras.
- Motor Other simple partial seizures include (clonic, jerking) convulsive movements. Jerking typically begins in one area of the body, the face, arm, leg, or trunk and may spread to other parts of the body. These seizures are sometimes called Jacksonian motor seizures; their spread is called a Jacksonian march. It cannot be stopped.
- Sensory Seizures Some simple partial seizures consist of a sensory experience. The person may see lights, hear a buzzing sound, or feel tingling or numbness in a part of the body. These seizures are sometimes called Jacksonian sensory seizures.
Simple partial seizures usually last just a few seconds, although they may be longer. If there are no convulsions, they may not be obvious to the onlooker.
In some children, simple partial seizures lead to complex partial seizures, or to tonic-clonic convulsions.
Startle epilepsy is a type of reflex epilepsy in which seizures are provoked by loud noises or sudden surprises. Most patients with startle epilepsy are only sensitive to one sensory modality (i.e. temperature, taste, sound, pressure); however, it is the unexpected nature of the stimulus, rather than the sensory modality, that characterizes startle epilepsy.
Patients with startle epilepsy usually have static cerebral lesions and developmental delay. Many of the patients are hemiparetic, meaning that half of the body is partially paralyzed, and it is the weak side of the body that is primarily involved in the startle seizures. Startle epilepsy is often associated with disorders such as infantile hemiplegia, Down syndrome, anoxic encephalopathy, and cortical dysplastic lesions.
These seizures usually last less than 30 seconds. The seizure begins with a startle response, followed by a brief tonic phase. Patients sometimes fall to the ground and experience clonic jerks. Responsiveness to the stimulus decreases as a result of repeated exposure to the stimulus. Spontaneous seizures also occur in patients with startle epilepsy, but are infrequent in most cases.
Carbamazepine, clonazepam, clobazam, and lamotrigine are sometimes prescribed for patients with startle epilepsy. Surgery has been reported to control startle epilepsy associated with infantile hemiplegia. However, startle epilepsy is typically intractable and patients can usually only achieve incomplete or temporary seizure control.
Status Epilepticus is considered a medical emergency. Immediate medical care is required.
Status epilepticus is a seizure which lasts for a long time, or repeats without recovery. This prolonged or repeated seizure activity can result in death if it is not treated immediately.
Status epilepticus can be convulsive (tonic-clonic or myoclonic seizures) or non-convulsive(absence or complex partial seizures). A person in non-convulsive status epilepticus may appear confused or dazed.
Status epilepticus and mortality in status epilepticus are more common among seniors than in the rest of the population. (Mortality in status epilepticus is recognized as death within 30 days of the event.) The highest incidence of status epilepticus occurs during the first year of life and after age 60.
In seniors, the majority of status epilepticus cases are related to:
- Cerebrovascular accidents
- Metabolic problems
- Decreased anticonvulsant medications, the level of the medication in the blood may have fallen too low. (This further shows the importance of taking your medication properly.)
Status epilepticus may occur as the first manifestation of a seizure disorder, or it may occur in a person known to have seizures. Status epilepticus is usually treated in hospital, where diazepam (Valium ®) or lorazepam (Ativan ®) is given intravenously. Phenobarbital is sometimes added intravenously. If your child is prone to status epilepticus, your doctor may teach you to administer diazepam or lorazepam suppositories at home.
While it is not believed to cause brain damage, it should be stopped as soon as possible.
Tonic seizures are very uncommon, especially when they occur without clonic jerking. They usually are manifest with Lennox-Gastaut syndrome or, less commonly, with multiple sclerosis. Tonic seizures most often develop in childhood, although they can occur at any age.
Tonic seizures are characterized by facial and truncal muscle spasms, flexion or extension of the upper and lower extremities, and impaired consciousness. Several types of tonic seizures exist. Those grouped with absence, myoclonic, and atonic seizures are non-convulsive and tend to be brief. The more prolonged seizures usually are convulsive and may manifest pupillary dilation, tachycardia, apnea, cyanosis, salivation, and the loss of bladder or bowel control. Tonic seizures are often followed by postictal confusion.
This type of seizure is seen when certain medications, such as barbiturates and benzodiazepines, are stopped abruptly. In this case, continued treatment with anti-epileptic medications is usually not advisable.
Withdrawal seizures are common when a person with alcoholism is trying to quit drinking. If a person with epilepsy drinks alcohol heavily and experiences withdrawal seizures, it is difficult for the physician or specialist to determine the exact cause of the seizure and to determine the next appropriate step. Therefore, it is important to avoid alcoholic beverages once you begin taking anti-epileptic medications.