Glossary
The medical terms used to describe the various aspects of epilepsy can be confusing. Use this simple glossary for definitions of some basic terms found on this Web site and elsewhere.
A
- Absence Seizure (also called Petit Mal)
- A sudden—but fleeting—loss of awareness, sometimes accompanied by staring, often without any prior warning or aftereffect.
- Adjunctive Therapy
- If the first drug treatment the healthcare professional prescribes is not effective enough alone, the healthcare professional may prescribe Adjunctive Therapy—another drug that is taken along with the first.
- AED
- Antiepileptic drug.
- Affective
- Having to do with feelings and emotional responses, including fear, foreboding, depression, happiness, and anger.
- Amnesia, Anterograde
- After a seizure, difficulty in remembering events that happened just before the seizure.
- Amnesia, Retrograde
- After a seizure, difficulty in remembering things one used to know.
- Antiepileptic Drug (also called Anticonvulsant)
- A drug used to bring seizures under control.
- Asymmetrical
- When movements during a seizure are noticeably different on each of the two sides of the body.
- Atonic Seizure (also called Drop Attack, Astatic Seizure, or Akinetic Seizure)
- A brief seizure during which muscles suddenly lose their tone and go limp without warning. Can occur as part of Lennox-Gastaut syndrome.
- Auditory
- Having to do with hearing, especially buzzing, drumming, droning, or other sounds caused by a seizure.
- Aura
- A warning—sometimes experienced as a feeling of strangeness—that sometimes comes just before a seizure. An aura is itself a small seizure that affects the senses. It may, but doesn’t always, become a larger seizure that others can observe.
- Automatism
- A set of repetitive, involuntary motions that can happen as part of a seizure. Often the motions are not remembered afterward. An automatism can look like a voluntary movement, and may resemble a movement made just before the seizure began.
B
- Bilateral (also called Generalized)
- Affecting both sides of the brain or body.
C
- Catamenial
- Used to describe seizures that always or regularly occur in some specific phase of a woman’s menstrual cycle.
- Cephalic
- Used to describe feelings of light-headedness or headache.
- Clonic Seizure (also known as Rhythmic Myoclonus)
- An epileptic seizure in which certain muscle groups jerk repetitively.
- Cluster
- A grouping of seizures within a single day or over a few days, especially when the grouping adds up to more seizures than usually experienced.
- Convulsion
- A seizure involving excessive and unusual muscle contractions, usually affecting both sides of the body.
D
- Dacrystic
- Used to describe crying or sobbing associated with a seizure.
- Déjà-vu
- An uncanny feeling of familiarity with something unfamiliar.
- Drop Attack (see Atonic Seizure)
- Duration
- The time from the start of a seizure (including the aura, if one occurs) until the end of the seizure (not including any postseizure feeling or states).
E
- Electroencephalograph (EEG)
- A recording of the electrical activity of the brain, used to identify some of the characteristics of epilepsy, such as spikes and waves.
- Epileptic Seizure
- An event that takes place when nerve cells fire much more rapidly and with less control than normal. Seizures can affect movements, the senses, concentration, the ability to communicate—even consciousness.
- Epileptologist
- A neurologist who specializes in treating patients with epilepsy.
- Experiential
- Used to describe out-of-context emotions, memories, or perceptions, including complex and vivid hallucinations.
F
- First-Line Therapy
- The first drug treatment prescribed by a healthcare professional. If it is not effective enough alone, the healthcare professional may prescribe Adjunctive Therapy—another drug taken along with the first.
- Focal Seizure (also known as a Partial Seizure)
- Focal seizures affect just one part of the brain. Partial seizures can interfere with awareness and the ability to communicate; they can also make the body move involuntarily. Focal seizures are the most common type of seizure. A focal seizure can stimulate emotions and the senses, make the body move, interfere with perceptions, generate perceptions, and produce vivid, extended hallucinations that can be seen and/or heard by the person having the seizure.
G
- Gelastic
- Used to describe laughter or giggling associated with a seizure.
- Generalized Seizure (also known as a Bilateral Seizure)
- Generalized seizures affect both sides of the brain at the same time, from the time the seizure begins. Consciousness is lost—often for a short time, but sometimes for much longer. Absence Seizures, Atonic Seizures, Myoclonic Seizures, and Tonic-Clonic Seizures are all generalized seizures.
- Generalized Tonic-Clonic Seizure (also known as a Bilateral Tonic-Clonic Seizure or Convulsions; formerly known as a Grand Mal Seizure)
- During a tonic-clonic seizure, the body stiffens (the tonic phase) and the limbs and face begin to jolt and shake (the clonic phase). During the tonic phase, breathing may slow down or even pause; in a typical tonic-clonic seizure, when the convulsive movements begin, breathing returns. The jerking and jolting of the clonic phase often lasts less than a minute.
- Gestural
- Used to describe groping movements of the hand associated with a seizure.
- Gustatory
- Used to describe sensations of taste—bitter, tart, salty, sweet, metallic—associated with a seizure.
H
- Hallucinatory
- Used to describe vivid, complex impressions involving some or all of the senses but associated with a seizure rather than with external events.
- Hyperkinetic
- Used to describe rapid movements associated with a seizure.
- Hypokinetic
- Used to describe a shutdown of ongoing movements associated with a seizure.
I
- Ictus
- A sudden neurological incident such as an epileptic seizure.
- Impaired Cognition
- Used to describe difficulty in thought, perception, attention, emotion, memory, or speech because of a seizure.
- Incidence
- The number of epileptic seizures within a given time period.
- Interactive
- Used to describe seizures that are environmentally influenced.
J
- Jamais-vu
- An uncanny feeling of unfamiliarity with something familiar.
K
- Kinetic
- Relating to motion.
L
- Lennox-Gastaut Syndrome
- One of the most severe and difficult-to-control forms of epilepsy, Lennox-Gastaut syndrome accounts for up to 10% of all cases of childhood epilepsy. (For more, see our Web page About Lennox-Gastaut syndrome.)
M
- Magnetic Resonance Imaging (MRI)
- A magnetic scanning technique used to create a detailed image of the brain.
- Mimetic
- Used to describe a facial expression that seems to be associated with an emotion—often fear—but that is actually caused by a seizure.
- Mnemonic
- Used to describe distortions involving memory—such as deja-vu and jamais-vu—due to a seizure.
- Monotherapy
- Treatment for epilepsy using a single drug instead of a combination of drugs.
- Motor
- Involving muscles and movement.
- Myoclonic Seizure
- During a myoclonic seizure, the muscles contract rapidly for a brief time. Sudden jerking motions occur on both sides of the body or sometimes in one foot or arm.
N
- Neurologist
- A healthcare professional who is an expert at diagnosing and treating conditions and diseases of the central nervous system.
- Neuron
- A nerve cell.
O
- Olfactory
- Used to describe the sensation of an odor, usually unpleasant, associated with a seizure but not with an external event.
- Oroalimentary
- Used to describe movements of the mouth, tongue, throat, and jaw associated with a seizure.
P
- Partial Seizure (also known as a Focal Seizure)
- Partial seizures affect just one part of the brain. Partial seizures can interfere with awareness and the ability to communicate; they can also make the body move in ways that can’t be controlled. Partial seizures are the most common type of seizure. A partial seizure can stimulate emotions and the senses, make the body move, interfere with perceptions, generate perceptions, and produce vivid, extended hallucinations that can be seen and/or heard by the person having the seizure.
- Perception
- The mental picture formed based on the information the senses provide—or seem to provide.
- Polytherapy
- Treatment of a single condition with more than one drug.
- Positron Emission Tomography (PET)
- A scan that uses a radioactive substance to find the part of the brain where seizures originate.
- Postictal
- Just after a seizure.
- Prodrome
- A change of feeling or behavior that signals the onset of a seizure but is not a part of it.
R
- Reactive
- Used to describe a seizure that happens in part because of or along with an illness, lack of sleep, or stress.
- Respiratory
- Having to do with breathing.
S
- Sensory
- Used to describe a seizure that produces perceptions triggered by the seizure rather than by an external event.
- Severity
- Assessment of a seizure based on how long it lasts, what movements are involved, how it affects thinking, feeling, and perceptions, how often seizures occur, and extent of injury and other consequences.
- Side Effects
- An unwanted effect of medication such as dizziness or trouble concentrating.
- Spike
- Unusual electrical activity in a group of neurons, producing a distinctive electroencephalograph (EEG) reading for patients with epilepsy.
- Spontaneous
- Used to describe a seizure that is not due to the environment.
- State Dependent
- Used to describe seizures that always or regularly occur in some specific stage of sleep or wakefulness.
- Status Epilepticus
- Most seizures are brief. But when seizures go on for too long, or come in clusters, a person may be at risk for a condition called status epilepticus—an ongoing state of seizure. Status epilepticus requires emergency treatment.
- Synchronous
- Movements that happen at the same time or at the same rate.
T
- Temporal Lobe
- A part of the brain often involved with epileptic seizures, the temporal lobe plays a vital role in memory and speech.
- Therapeutic Range
- A guide used by healthcare professionals to help determine the right dosages for antiepileptic drugs.
- Titration
- The process of bringing the dosage of a medication up to the level at which it has the desired effect.
- Tonic Seizure
- Increased muscle contractions lasting from a few seconds to a few minutes.
- Tonic-Clonic Seizure
- During a tonic-clonic seizure, the body stiffens (the tonic phase) and the limbs and face begin to jolt and shake (the clonic phase). During the tonic phase, breathing may slow down or even pause; in a typical tonic-clonic seizure, when the convulsive movements begin, breathing returns. The jerking and jolting of the clonic phase often lasts less than a minute.
U
- Unilateral
- Used to describe a seizure in which one side of the body is involved.
V
- Verbal
- Used to describe a seizure in which speech is involved.
- Visual
- Used to describe a seizure in which visual phenomena, such as flickering lights, spots, or patterns, are involved.
- Vocal
- Used to describe a seizure in which noises such as growling, grunting, or shouting are involved.
For more definitions, try one of these sources: