The following definitions are included to help further your general knowledge of epilepsy terminology.


Absence Seizure (Petit Mal Seizure): — A type of generalized seizure usually seen in children, characterized by staring and accompanied by a 3-per-second spike-and-wave pattern on the electroencephalograph. These seizures respond well to medication, and most children outgrow them. May also be described as a “generalized non-motor seizure”.

Adjunctive Therapy — Taken with other medications.

Anticonvulsant (antiepileptic drug) — A medicine used to control both convulsive and non-convulsive seizures.

Arteriovenous Malformation — A tangle of arteries and veins which can cause headaches, seizures, or bleeding in the brain. Often requires surgery.

Automatisms — Involuntary movements that accompany seizures, such as chewing, fumbling at a button, or pulling on clothes. Can occur in generalized or partial seizures.

Ataxia — A type of clumsiness, often the result of too much medication.

Aura — A warning that a seizure may begin, often described as a “funny feeling.” An aura is actually a small seizure that may develop into a larger seizure or disappear.

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Benign Rolandic Epilepsy — Accounts for almost 25% of seizures appearing in children from age 5 to 14. Not always treated with medication, because seizures typically outgrown by adolescence.

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Catamenial — Related to a woman’s monthly period.

Cerebrovascular — Relates to the blood supply in the brain, involving the cerebrum and blood vessels.

Clonic Seizure — An epileptic seizure characterized by jerking.

Corpus Callosum — The white matter that connects the 2 hemispheres of the brain. A corpus callosotomy is an operation in which a part or all of this structure is cut, disconnecting the 2 hemispheres. This surgery is typically reserved for patients with intractable generalized epilepsy, such as Lennox-Gastaut syndrome.

Complex Partial— Seizure that alters consciousness causing confusion.

Complex Partial With Secondary Generalization — Seizure that starts as complex partial but becomes a generalized seizure affecting both sides of the brain.

Computerized Axial Tomography — A CAT or CT scan. This type of x-ray uses a computer to assemble multiple images, producing a detailed picture of the skull and brain.

Comprehensive Epilepsy Centre — A medical facility consisting of an epilepsy clinic and epilepsy monitoring unit usually staffed by neurologists, neurosurgeons, neuroradiologists, neuropsychologists, technologists, a clinical coordinator, and a social worker specially trained to help people with epilepsy. An epilepsy centre may employ sophisticated technology such as magnetic resonance imaging, single photon emission computerized tomography, and positron emission tomography scans to research epilepsy help diagnose and .

Convulsion (Grand Mal Seizure): — A seizure characterized by stiffening of the body and jerking, excess salivation (foaming at the mouth), and loss of control of urine, followed by a period of confusion.

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Déjà Vu — A psychic seizure that produces a false sense of familiarity, as if life is repeating itself.

Depth Electrode — A special electrode placed inside the brain through a small hole in the skull to locate a seizure focus.

Double Blind — A clinical trial in which medication is coded so that neither the neurologist nor the patient knows whether placebo or active medication is being used.

Drop Attack — Often seen in Lennox-Gastaut syndrome, a type of seizure that causes the child to suddenly fall. May cause injuries of the face and head.

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Electrode — A small metal contact attached to a wire designed to record brain waves from the scalp or inside the brain.

Electroencephalogram (EEG) — A tracing of brain waves, used to search for epileptic spikes and abnormal slowing.

Encephalitis — An inflammation in the brain caused by infection. May be accompanied by seizures and result in epilepsy later in life.

Epilepsia Partialis Continua — A rare seizure type that consists of repeated jerking lasting long periods of time. Often seen in Rasmussen’s encephalitis.

Epileptic Focus — The site in the brain where a seizure begins.

Epileptologist — A neurologist with special training who treats patients with epilepsy.

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Febrile Seizure — A seizure caused by a high fever in children under the age of 5. Most of these children do not develop epilepsy.

Fit — A seizure.

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Gastroenteritis — Swelling of the lining of the stomach and intestines. Generalized Seizure — A seizure that affects both hemispheres of the brain. Grand Mal Seizure — A convulsion.

Grid — An array of electrodes placed on the brain to locate a seizure focus or map speech.

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Half-Life — The time required for half the amount of drug to disappear from the body.

Hemispherectomy — A type of epilepsy surgery in which one of the hemispheres of the brain is removed or disconnected. Can be extremely helpful in controlling seizures in appropriate patients.

Hypoglycemia — An abnormal decrease of glucose/sugar in the blood.

Hypsarrhythmia — Specific patterns of irregular high-amplitude slow waves and spikes on the electroencephalogram seen in West’s syndrome.

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Infantile Spasms — A type of seizure that occurs in infants, characterized by frequent jerks of the body. Part of West’s syndrome.

Intractable — Refers to seizures that cannot be stopped by medication.

Intravenous — Medications or fluids administered through a needle inside a vein.

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Juvenile Myoclonic Epilepsy — A seizure syndrome that usually appears at puberty.

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Ketogenic Diet — a special high-fat, low-carbohydrate diet that helps to control seizures in some people with epilepsy. It is prescribed by a physician and carefully monitored by a dietitian.

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Lennox-Gastaut Syndrome — A type of epilepsy occurring in infancy and early childhood characterized by frequent seizures and multiple seizure types. These children have mental retardation and slow spike- and-wave complexes on their electroencephalograms. This type of epilepsy is extremely difficult to control.

Liver Function Test Abnormality — An elevation of liver enzymes, which can be caused by antiepileptic medications. This is a common finding on blood tests and not a cause for concern unless the level is very high.

Low White Count — An abnormality detected on a complete blood count (CBC), often a side effect of antiepileptic medications. Rarely of clinical significance.

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Magnetic Resonance Imaging (MRI) — A scan that uses an enormous magnet instead of x-rays to form an extremely detailed image of the brain.

Magnetic Resonance Angiography — A magnetic scan of the blood vessels of the brain. Does not require any contrast material (dye).

Magnetic Resonance Spectroscopy — A method of measuring brain metabolism using a magnetic scanner to identify a seizure focus.

Magnetoencephalography — An experimental device that measures minute magnetic fields produced by ionic currents in the brain; may help localize an epileptic focus.

Meningitis — An inflammation of the covering of the brain.

Menopause — The time when menstruation naturally stops in women. Usually occurs around age 50.

Monotherapy — Single-drug treatment for epilepsy.

Myoclonic Seizure: Seizure characterized by sudden jerking of the muscles, similar to the effect of being hit by a jolt of electricity.

Myoclonus — A sudden muscle jerk of the body. Can be seen in a number of different epilepsy syndromes.

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Neurologist — A doctor who is trained to diagnose and treat diseases related to the nervous system.

Neuron — A nerve cell. Billions of neurons interact to make up a working brain. Epileptic discharges are produced when groups of neurons misfire.

Neurotransmitter — Chemicals that carry impulses from one neuron to another.

Nystagmus — Bouncing eye movements, often the result of medication toxicity.

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Open Label — A clinical trial in which the name and dosage of the investigational drug are known to the investigator and patient.

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Partial Seizure — A seizure that begins in a specific location in the brain, such as the temporal lobe.

Partial Complex Seizure — A seizure that begins in a specific location in the brain and alters consciousness, causing confusion.

Partial Simple Seizure — See Simple Partial

Petit Mal Seizure —See absence seizure.

Placebo — An inactive substance sometimes used as a basis for comparison when new drugs are tested.

Polytherapy — Treatment with multiple drugs.

Positron Emission Tomography (PET) — A scan that uses an injection of radioactive tracer to measure brain metabolism in an effort to locate the seizure focus. Often part of the evaluation before seizure surgery.

Postictal — The period immediately after a seizure.

Protocol — The specific manner in which a clinical trial is conducted.

Pseudoseizure — Clinically resembles an epileptic seizure but without epileptic discharges from the brain. Also called psychogenic or nonepileptic seizure, most often caused by severe psychosocial stress.

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There are currently no glossary items for the letter “Q”.

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Rasmussen’s Encephalitis — A type of chronic, progressive brain inflammation that produces uncontrolled seizures. May be successfully treated by hemispherectomy.

Respiratory — Relating to the process of breathing.

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Simple Partial — A seizure that that begins in a specific location in the brain but does not alter consciousness. May produce abnormal sensations, such as an unpleasant smell, or a motor movement, such as jerking of the arm.

Single Photon Emission Computerized Tomography (SPECT) — A scan that uses an injection of a radioactive tracer to measure blood flow in the brain. Typically 2 SPECT scans are done, one during a seizure and one in between seizures. SPECT scans can help identify a seizure focus in preparation for surgery.

Spike — A characteristic finding on the electroencephalograph in patients with epilepsy. A spike is the result of an abnormal synchronized electrical discharge in a population of neurons.

Status Epilepticus — A condition of recurrent seizures on the same day or prolonged seizures requiring immediate medical attention.

SUDEP – Sudden Unexpected (Unexplained) Death in Epilepsy is a rare cause of death for people with Epilepsy. There is no known cause.

Synapse — The place at which a nerve impulse passes from one neuron to another.

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Telemetry — Continuous monitoring of the electroencephalogram, often with video.

Temporal Lobe — A part of the brain important in memory and controlling speech. Often the site of the epileptic focus.

Therapeutic Range — A blood level guide, for some antiepileptic drug levels. Patients often require more or less medication to control their seizures than suggested by the therapeutic range listed on the laboratory report.

Todd’s Paralysis — A temporary weakness of an arm, leg, or other body part after a seizure.

Tonic-clonic Seizure — An epileptic seizure characterized by a fall to the ground (tonic phase) followed by jerking movements (clonic phase).

Tuberous Sclerosis — An inherited disorder, typically with mental retardation, abnormalities of the brain, skin, and other organs, and seizures. Half these patients will have infantile spasms.

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There are currently no glossary items for the letter “U”.

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Vagal Stimulator — A device designed to control seizures, similar to a cardiac pacemaker, but with the electrode attached to the vagus nerve in the neck.

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Wada Test — Not an abbreviation, but named after its developer, Dr. Jun Wada. This is an injection into the carotid artery of amobarbital, used to determine the location of the brain’s speech center and to test memory prior to epilepsy surgery.

West’s Syndrome — A type of epilepsy in infants characterized by abrupt spasms of the body that usually occur in clusters, mental retardation, and the recognizable pattern on the electroencephalograph called hypsarrhythmia.

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There are currently no glossary items for the letter “X”.

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There are currently no glossary items for the letter “Y”.

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There are currently no glossary items for the letter “Z”.

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