Epilepsy Terms Glossary

absence seizure

(formerly called petit mal) generalized seizure most common in children; a lapse in consciousness with a blank stare that begins and ends within a few seconds. May be accompanied by rapid eye blinking or chewing movements.

adjunct therapy

(syn.: add-on therapy) treatment administered in addition to another therapy, as when one medication is taken with another.

Adjunctive

Additional, add on. As in adjunct or adjunctive therapy, concerning a drug which is added to an existing medication.

AED (anti-epileptic drug)

a seizure-preventing drug. AEDs are carried to the brain through the bloodstream.

Affect

Mood, level of emotional responsiveness.

Affective

Concerning or influencing mood and level of responsiveness.

American Epilepsy Society

Founded 1946. The professional society for physicians dealing with epilepsy and closely related fields. AES focuses on treatment of biological, clinical and social aspects of epilepsy.

Amygdala

Part of the limbic system of the brain. Seizures arising in this area include a rising sensation in the stomach, nausea, movements of the mouth, chewing, fear, panic, and flushing of the face and other autonomic symptoms.

aneurism

bulge in a blood vessel caused by a weakness in the vessel wall; sometimes a cause of seizures when it occurs in the brain.

Angelman syndrome

a genetic disorder marked by mental retardation, speaking difficulties, inappropriate laughter and hyperactivity; most children with this syndrome also have epilepsy.

anticonvulsant

preventing or arresting convulsions; agent that prevents convulsions

antiepileptic

preventing seizures; there is no agent that prevents epilepsy.

Aphasia

Defect in or loss of the ability to express oneself using speech, writing, or signs, or to comprehend spoken or written language as a result of injury to or disease of the brain's speech centers.

Apnea

Cessation of breathing.

ataxia

inability to coordinate muscle movement

atonic seizure

(syn. drop attack) generalized seizure where sudden complete loss of muscle control and balance results in collapse

aura

a sensation recognized by a patient that precedes or signals the beginning of a seizure. May include uneasiness, deja vu, sensory illusions (odors, visual illusions or misconceptions, sounds), stomach discomfort, dizziness.

Automatism

Involuntary, undirected movements during complex partial seizures and atypical absence seizures.

bioavailability

the amount of a drug in a capsule or tablet that is actually metabolized.

bioequivalency

equal performance of two or more substances used as therapy.

blood level monitoring

monitoring of levels of antiepileptic drugs in the bloodstream. Blood samples are taken to ensure that a proper amount of the drug is being metabolized.

breakthrough seizures

seizures that occur despite drug therapy.

CAT scan (computerized axial tomography)

(syn.: CT scan) imaging technique that creates three-dimensional images of the brain and shows possible abnormalities.

Catamenial epilepsy

Epilepsy in which there is a tendency for a woman's seizures to occur primarily at the time of menstruation.

cavernous angioma

an abnormal tangle of blood vessels; sometimes causes seizures when it occurs in the brain.

cerebellum

a brain structure involved in the control and coordination of voluntary muscle movements.

chronic

affecting a person fora long period of time; a slowly progressing and continuing disorder.

clonic

seizure involving muscle contractions and relaxations.

clustering

involves repeated seizures that follow immediately upon one another or which happen within hours of each other following periods without seizure activity.

cognition

the process by which knowledge is acquired; awareness, thinking, learning and memory

complex partial seizure

usually starts with a blank stare, followed by random activity. Person appears unaware of surroundings, seems dazed and mumbles, is unresponsive, clumsy. When seizure ends, post-ictal confusion often follows, and the person has no memory of what happened during the seizure. This type of seizure activity is localized mainly to one part of the brain.

Compliance

Refers to patient adherence to physician directions for taking antiepileptic drugs.

convulsion

involuntary muscle contractions common in generalized tonic-clonic seizures.

corpus callostomy

severing of nerve fibers that connect the two hemispheres of the brain in order to interrupt the spread of seizures from one side of the brain to the other. (See: surgery for epilepsy.)

cortex

(cerebral cortex) the thin outer layer of the brain that controls movement and the senses.

cortical displasia

abnormal development of the cortext, a condition that can cause seizures.

craniotomy

an opening made into the skull for brain mapping and epilepsy surgery.

Cryptogenic

Of unknown origin.

depth electrodes

thin wires placed deep in the brain to detect seizure activity that cannot be recorded from the surface of the brain.

EEG (electroencephalograph)

apparatus that records, in the form of brain waves, electrical discharge from neurons in the brain through electrodes attached to the scalp.

encephalitis

inflammation of the brain from an infection or as the result of other diseases; sometimes causes epilepsy.

epilepsy

chronic neurological disorder characterized by recurrent seizures; estimated to affect 2.7 million Americans.

Epilepsy Foundation

Founded 1967 as the Epilepsy Foundation of America. National office: Landover, MD. The voluntary non-profit organization that provides local and national services for people with epilepsy, and funds research into causes and cures for the disorder.

epileptologist

a physician (neurologist) expert in teh diagnosis and treatment of epilepsy.

etiology

study of the cause of a disease or medical condition.

febrile seizure

seizure related to high fever in babies and children, usually under age five. Most children who have a febrile seizure do not develop epilepsy.

Focal seizure

an epileptic seizure that involves one hemisphere of the brain. (See also: generalized seizure, partial seizure.)

Focus

Identified area of the brain from which partial seizures arise.

frontal lobe

located in upper region of the head, behind the forehead; frontal lobe controls decision-making, problem-solving or planning and motor movement. (See Also: lobe, parietal lobe, temporal lobe, occipital lobe.)

gamma knife surgery (radio surgery)

a form of radiation therapy that uses gamma rays to destroy seizure-causing tissue in the brain.

generalized seizure

a epileptic seizure that involves the whole brain. (See also: types of generalized seizures: tonic-clonic and absence.)

grand mal

(See: tonic clonic.)

hemispherectomy

surgical removal of one hemisphere of the brain; with epilepsy, performed almost exclusively in children for whom severely damaged tissue spanning one hemisphere produces uncontrollable seizures. (See Also: surgery for epilepsy.)

hippocampal sclerosis

cell loss and hardening of the hippocampus, the brain structure that lies in the temple areas.

hippocampus

with the amygdala, the septum, and parts of the cortex, comprises the brain?s limbic system; hippocampus is partly responsible for memory.

Hyperventilation

Rapid, deep breathing. Use in EEG testing may produce abnormalities or even a seizure.

Ictal

Pertaining to, characterized by, or caused by an epileptic seizure.

ictus

a seizure; a stroke.

Idiopathic

Of unknown origin or cause.

incidence

the frequency with which epilepsy occurs over time; about 200,000 epilepsy cases develop in the United States each year.

infantile spasms

myoclonus seizures; generalized seizures causing the clonic spasms of a muscle or muscle group in an infant.

interictal

the period of time between one seizure and another.

International Bureau for Epilepsy (IBE)

Founded 1961. The international lay organization concerned with medical, social, and scientific aspects of epilepsy which exchanges information and experience on care of patients with seizures.

International Classification

developed by the International League Against Epilepsy, a periodically updated classification of seizure types, behaviors, and causes used to characterize seizure disorders and epileptic syndromes. ILAE classifies seizures according to the location in the brain where the seizure activity takes place: generalized or partial. (See Also: generalized seizure and partial seizure.)

International League Against Epilepsy (ILAE)

Founded 1909. Headquarters: Bethesda, MD. The international professional organization for physicians which encourages scientific research on epilepsy and the exchange of information.

Intractable

Not responding to treatment.

ketogenic diet

stringent, high fat, low carbohydrate diet that controls seizures in some children.

Lafora disease

a rare form of myoclonic epilepsy leading to progressive disability, dementia and a shortened lifespan.

Landau-Kleffner syndrome

A rare, childhood condition producing seizures and progressive loss of the ability to speak.

Lennox-Gastaut syndrome

debilitating epileptic syndrome in children characterized by myoclonic, absence, and tonic-clonic seizures.

lesion

wound or injury which results in pathological change in tissue (e.g. head injury which results in seizure-causing lesions in the brain). Lesions are sometimes surgically removed to reduce or prevent recurring seizures.

limbic system

the group of brain structures that influence the body?s unconscious movement and hormonal activity.

lissencephaly

refers to an abnormal smooth brain without folds.

lobe

any rounded, projecting part of the anatomy; components of the brain. (See Also: frontal lobe, parietal lobe, temporal lobe, and occipital lobe.)

lobectomy

surgical removal of a lobe; surgical removal of all or part of the lobe of the brain bearing abnormal seizure-causing tissue (e.g., temporal lobectomy). (See Also: surgery for epilepsy.)

Magnetic resonance imaging

An imaging method using magnets instead of X-rays. Produces detailed pictures of the internal structure of the brain.

march

progression of muscular convulsions from one muscle or muscle group to another.

MEG (magnetoencephalography)

records magnetic activity generated by the brain?s electrical activity; helps identify brain areas where seizures begin.

meningitis

inflammation of the membranes of the brain and spinal cord; sometimes causes epilepsy.

mesial temperal sclerosis

(See: hippocampal sclerosis)

Monotherapy

Treatment with a single drug.

mortality

death rate; often given as ratio of deaths per 100,000.

multifocal epilepsy

epilepsy in which the seizures come from a number of locations in the brain.

multiple subpial transcetion (MST)

surgery in which shallow parallel cuts are made in the cortex; used to reduce or eliminate seizures that come from critical brain areas that cannot be removed.

myoclonus

usually generalized seizures causing massive rapid clonic spasms of muscle or group of muscles.

neurocystircercosis

a parasitic brain infection from eating bad pork; a common cause of seizures in some US immigrants.

neurologist

a specialist in the diagnosis and treatment of nervous system diseases and disorders such as epilepsy.

nocturnal seizures

seizures which occur routinely in evening hours.

nonepileptic seizures

seizures with a psychological cause or which are due to a sudden drop in blood pressure, low blood sugar, or other temporary condition.

occipital lobe

brain lobe at the rear of the head identified with vision.

parietal lobe

brain lobe which interprets sensory input and the body?s relation to space.

partial seizure

seizure involving only one part of the brain, categorized as either simple partial or complex partial. (See Also: focal seizure.)

perinatal

in development of a fetus, the period from the 28th week of gestation to 7 days after delivery; the period during which complications such as prolonged lack of oxygen or other trauma may result in epilepsy for a newborn.

petit mal

(See Also: absence seizure.)

pharmacotherapy

medication therapy.

phenobarbital

common AED; trade name Luminal.

phenytoin

common AED; trade name Dilantin.

photosensitivity

a reflex epilepsy in which seizures are triggered by flashing lights or patterns (e.g., strobe lights, video games, or flipping and rolling of a television screen). An estimated 3 % of people with epilepsy are photosensitive.

polytherapy

(syn.: polypharmacy) the use of two or more antiepileptic medications for control of seizures.

post-ictal confusion

temporary incoherence, inability to respond to contact or unfamiliarity with environment which commonly follows tonic-clonic, complex partial and atonic seizures.

Prodromal

Indicating the onset of a disease. In epilepsy, indicating the onset of a seizure.

pseudoseizure

(syn.: non epileptic attack disorder [NEAD]) a sudden disruptive change in a person's behavior which resembles epileptic seizures but has no electrophysiological changes in the brain. NEADs may be related to physical illness, psychiatric disorder or emotional attacks.

reflex epilepsy

rare epilepsy which occurs in response to specific sensory stimulus, including flickering light or patterns, sounds, tastes, smells, movements or sensations of touch.

Refractory

Difficult to treat, unresponsive or of limited response to medication.

seizure

abnormal electrical discharge in the brain. Seizures can be related to injury, high fever, substance abuse, metabolic disorders, and other health conditions such as diabetes, and are not always a sign of epilepsy.

seizure prediction

complex automated brainwave analysis that can predict an oncoming seizure up to 30 minutes or more before it is clinically apparent.

seizure semiology

the clinical symptoms of a seizure.

seizure threshold

the point at which a person can no longer tolerate a seizure-provoking stimulus (e.g., babies have a lower seizure threshold for high body temperature than do adults. High fever can trigger febrile [fever-related] seizures in babies.

simple partial seizure

seizure activity in one part of the brain resulting in: a.) jerking in one area of the body, arm, leg or face; b.) partial sensory seizures where a patient experiences distorted environments, sensory illusion or gastric discomfort. The motor or sensory activity may progress to a convulsive seizure.

Single-photon emission computerized tomography

(SPECT) An imaging technique to measure blood flow in the brain.

spikes and waves

the brainwave pattern on an EEG tracing during a seizure.

status epilepticus

severe, potentially life-threatening non-stop seizures, not always related to epilepsy; status epilepticus can result from acute brain injury.

stereotactic surgery

brain surgery performed with the head held in an immoveable position by a special positioning device.

subdural

referring to the area beneath the tough membrane (dura) which forms the outer envelope of the brain; subdural strips or grids are small plastic devices containing electrodes which are placed directly on the brain surface to record brain wave activity.

SUDEP (sudden unexplained death in epilepsy)

a rare condition in which death occurs without an apparent cause but which is presumed to be related to the person's epilepsy.

surgery for epilepsy

removal of the part or parts of the brain determined to cause seizures in a patient for whom medications prove ineffective. Surgery candidates must undergo a battery of tests and evaluations to ensure all alternatives have been exhausted, to pinpoint the area of the brain where seizures begin, and to map areas which must be preserved. (See Also: lobectomy, hemispherectomy, corpus callosotomy.)

syncope

fainting due to a loss of blood flow to the brain; sometimes misdiagnosed as seizures.

syndrome

a set of symptoms characterizing a disease, disorder, or condition. An epilepsy syndrome is the complete set of seizure types and symptoms experienced by a patient. The International Classification of the Epilepsies and Epileptic Syndromes (1985) identifies more than 11 widely accepted epileptic syndromes.

temporal lobe seizure

a partial seizure involving the temporal lobe. Symptoms vary but may include visual and auditory hallucinations or distortions, deja vu, feelings of detachment from surroundings and automatisms. Consciousness may be impaired or lost.

temporal lobes

the areas of the brain that lie at the side of the head behind the temples and which are involved in hearing, memory, emotion, language, illusions, tastes, and smells. (see also lobe, anterior lobe, occipital lobe, parietal lobe.)

teratogenic

a medication or treatment with the potential to cause birth defects.

tonic-clonic

most conspicuous type of seizure; generalized seizures which usually begin with a sudden cry, fall and rigidity (tonic phase) followed by muscle jerks, shallow breathing or temporarily suspended breathing and change in skin color (clonic phase), possible loss of bladder or bowel control; seizure usually lasts a couple of minutes, followed by a confusion and fatigue.

trans cranial magnetic stimulation

an unproven experimental procedure that exposes the brain to a strong magnetic field as a potential treatment for epilepsy.

treatment

conventional treatment for epilepsy is drug therapy. Surgery is increasingly common and used in a growing number of patients each year. (See Also: ketogenic diet, vagus nerve stimulator.)

vagus nerve

a nerve which begins at the brain stem, passes through the cranial cavity past the jugular, to the throat, larynx, lungs, heart, esophagus, stomach and abdomen.

vagus nerve stimulator (VNS)

a device to reduce severity of seizures through electrical stimulation of the vagus nerve. Device is implanted in the upper left chest with electrodes encircling the vagus nerve. Electrical impulses are sent at set intervals to the brain.

valproic acid

common AED; trade name Depakote?liquid form, Depakene?pill form.

video monitoring

simultaneous video (TV) monitoring and EEG recording of brain waves to help identify the type of seizure that is taking place.

Wada test (intracarotid sodium amobarbital)

test that helps locate speech and memory centers, named for creator Dr. J.A. Wada. An injection of amobarbital sedates one side or hemisphere of the brain. Doctors then check speech and memory to determine which side is the dominant area for these crucial brain functions.