absence epilepsy – epilepsy in which the person has repeated absence seizures.
absence seizures –seizures seen in absence epilepsy, in which the person experiences a momentary loss in consciousness. The person may stare into space for several seconds and may have some twitching or mild jerking of muscles. An older term for absence seizures is petit mal seizures.
atonic seizures – seizures which cause a sudden loss of muscle tone, also called drop attacks.
auras – unusual sensations or movements that warn of an impending, more severe seizure. These auras are actually simple focal seizures in which the person maintains consciousness.
automatisms – automatic involuntary or mechanical actions.
clonic seizures – seizures that cause repeated jerking movements of muscles on both sides of the body.
convulsions –sudden severe contractions of the muscles that may be caused by seizures.
corpus callosotomy – surgery that severs the corpus callosum, or network of neural connections between the right and left hemispheres
déjà vu – a sense that something has happened before.
de novo- new, for the first time.
Dravet syndrome –a type of intractable epilepsy that begins in infancy.
drop attacks – seizures that cause sudden falls; another term for atonic seizures.
epilepsy syndromes – disorders with a specific set of symptoms that include epilepsy.
febrile seizures – seizures in infants and children that are associated with a high fever.
focal seizures – seizures that occur in just one part of the brain.
frontal lobe epilepsy – a type of epilepsy that originates in the frontal lobe of the brain. It usually involves a cluster of short seizures with a sudden onset and termination.
generalized seizures – seizures that result from abnormal neuronal activity in many parts of the brain. These seizures may cause loss of consciousness, falls, or abnormal movements such as convulsions.
grand mal seizures – an older term for tonic-clonic seizures.
hemispheres – the right and left halves of the brain.
hemispherectomy– surgery involving the removal or disabling of one hemisphere of the brain.
hemispherotomy – removing half of the brain’s outer layer (cortex).
hypothalamic hamartoma – a rare form of childhood epilepsy that is associated with malformations of the hypothalamus at the base of the brain.
infantile spasms – clusters of seizures that usually begin before the age of 6 months. During these seizures the infant may bend and cry out.
intractable – hard to treat; about 30 to 40 percent of people with epilepsy will continue to experience seizures even with the best available treatment.
juvenile myoclonic epilepsy – a type of epilepsy characterized by sudden muscle (myoclonic) jerks that usually begins in childhood or adolescence.
ketogenic diet – a strict diet rich in fats and low in carbohydrates that causes the body to break down fats instead of carbohydrates to survive.
Lafora disease – a severe, progressive form of epilepsy that begins in childhood and has been linked to a gene that helps to break down carbohydrates.
Lennox-Gastaut syndrome – a type of epilepsy that begins in childhood and usually causes several different kinds of seizures, including absence seizures.
lesion – damaged or dysfunctional part of the brain or other parts of the body.
lesionectomy – surgical removal of a specific brain lesion.
lobectomy – surgical removal of a lobe of the brain.
monotherapy – treatment with only one antiepileptic drug.
multiple subpial transection – a type of operation in which surgeons make a series of cuts in the brain that are designed to prevent seizures from spreading into other parts of the brain while leaving the person's normal abilities intact.
myoclonic seizures – seizures that cause sudden jerks or twitches, especially in the upper body, arms, or legs.
neocortical epilepsy – epilepsy that originates in the brain's cortex, or outer layer. Seizures can be either focal or generalized, and may cause strange sensations, hallucinations, or emotional changes.
nonconvulsive – any type of seizure that does not include violent muscle contractions.
nonepileptic seizures – any phenomena that look like seizures but do not result from abnormal brain activity. Nonepileptic events may include psychogenic seizures or symptoms of medical conditions such as sleep disorders, Tourette syndrome, or cardiac arrhythmia. Pseudoseizure is an older term for nonepileptic seizure.
post-ictal – post-seizure.
prodrome – a feeling that a seizure is imminent, which may last hours or days prior to the seizure.
progressive myoclonus epilepsy – a type of epilepsy that has been linked to an abnormality in the gene that codes for a protein called cystatin B. This protein regulates enzymes that break down other proteins.
Rasmussen's encephalitis – a progressive type of epilepsy in which half of the brain shows continual inflammation.
responsive stimulation – a form of treatment that uses an implanted device to detect a forthcoming seizure and administer intervention such as electrical stimulation or a fast-acting drug to prevent the seizure from occurring.
seizure focus – an area of the brain where seizures originate.
seizure threshold – a term that refers to a person's susceptibility to seizures.
seizure triggers –phenomena that trigger seizures in some people. Seizure triggers do not cause epilepsy but can lead to first seizures or cause breakthrough seizures in people who otherwise experience good seizure control with their medication.
status epilepticus – a potentially life-threatening condition in which a seizure is abnormally prolonged. Although there is no strict definition for the time at which a seizure turns into status epilepticus, most people agree that any seizure lasting longer than 5 minutes should, for practical purposes, be treated as though it was status epilepticus. Repeated seizures without regaining consciousness between the events is also considered a form of status epilepticus.
sudden unexpected deathin epilepsy (SUDEP) – death that occurs suddenly for no discernible reason. Epilepsy increases the risk of unexplained death about two-fold.
temporal lobe epilepsy – the most common epilepsy syndrome with focal seizures.
temporal lobe resection – a type of surgery for temporal lobe epilepsy in which all or part of the affected temporal lobe of the brain is removed.
tonic seizures – seizures that cause stiffening of muscles of the body, generally those in the back, legs, and arms.
tonic-clonic seizures – seizures that cause a mixture of symptoms, including loss of consciousness, stiffening of the body, and repeated jerks of the arms and legs. In the past these seizures were sometimes referred to as grand mal seizures.
vagus nerve stimulator – a surgically implanted device that sends short bursts of electrical energy to the brain via the vagus nerve and helps some individuals reduce their seizure activity.