Seizure terminology: A glossary

Absence seizure — A type of generalised onset seizure, also known as a dialeptic seizure or a petit mal seizure. Characterised by blank stares and a brief loss of awareness, sometimes with blinking. They may last anywhere between 2–20 seconds. Usually, they develop in childhood, but are often outgrown and can be easily controlled with medication. 

Accommodation — Any change that gives people with disabilities an equal opportunity to work.

Adversive seizures — Seizures characterised by rotation of the head, eyes, or body.

Ambulatory EEG monitoring —  A system for recording the electroencephalogram outside of the hospital for a short period of time.

Anticonvulsants — A drug used to control seizures. 

Anti-epileptic drugs — Medications used to treat epilepsy, also called anticonvulsants or AEDs. 

Atonic seizure — Seizures characterised by the sudden loss of muscle tone, often in the arms or legs. Known to cause objects in hands to drop or sudden falls. 

Aura — Focal aware seizure. Some people use “aura” to describe a warning sign of a seizure 

Benign focal epilepsy of childhood — An epilepsy syndrome found in children characterised by focal aware seizures during sleep. Known to cause changes around the face or tongue, gurgling noises, or rapid movement of facial muscles. They are easily controlled with medication, but are often infrequent enough to be left untreated. Are usually outgrown by puberty.

Catamenial epilepsy — The tendency for people with epilepsy to experience seizures around the time of menstruation. 

Chronic epilepsy — When seizures are resistant to medication and other treatments.

Clonic seizure — Epileptic seizures characterised by sudden rhythmic movement involving all parts of the body.

Computed tomography — Also known as a ct or cat scan. a technique using x-rays and computers to create an image of the inside of a body, particularly of someone’s brain. Similar to an MRI but makes a lower resolution image. 

Corpus callosum — The major nerve structures that connect the two hemispheres of the brain. Helps to share information between each half of the brain. 

Corpus callosotomy — A surgery that cuts the corpus callosum to interrupt the spread of seizures between brain hemispheres. Most effective against atonic and tonic-clonic seizures. 

Drop attacks — A sudden fall without loss of consciousness, categorised as tonic or atonic seizures when part of epilepsy.

ECG (electrocardiogram) — Diagnostic test of the electrical activity of the heart. 

EEG (electroencephalogram) — Diagnostic test of the electrical activity of the brain.

EEG video monitoring — A continuous EEG test with accompanying video to observe behaviour. Used for diagnosing epilepsy, localising the seizure focus, and determining treatment.

EPC (epilepsia partialis continua) — Continuous or prolonged partial seizures. Characterised by sudden movement in the arms, legs, or face.

Epilepsy — A medical condition characterised by recurrent seizures caused by abnormal electrical activity in the brain.

Epilepsy surgery — A procedure to prevent further seizures. Successful in most patients depending on type of epilepsy.

Epilepsy syndrome — A disorder defined by a cluster of epilepsy symptoms occurring together with a known prognosis. 

Epileptogenic zone — The area of the brain responsible for the abnormal electrical signals that cause seizures.

Febrile seizures — Tonic-clonic seizures that are known to occur in young children as a result of fevers. 

Focal impaired awareness seizure Seizures that involve partially impaired awareness. Characterised by staring into space or unintentional movements.

Focal seizure — An older term for partial seizures. A seizure that begins in the focal area of the brain and may not spread to other parts.

Generalised seizure — A seizure that occurs in both hemispheres of the brain at once. May be convulsive or non-convulsive, and may cause tonic clonic or other movements. 

Grand-mal seizure — An older term for tonic-clonic seizures. Characterised by losing consciousness and collapsing, often with body stiffening or sudden muscle movements.

Hemisphere — Cerebral hemispheres, referring to one half of the brain.

Hemispherectomy — A surgical procedure to remove portions of one hemisphere of the brain to prevent seizures from spreading.

Idiopathic generalised epilepsies — Epilepsy syndromes characterised by onset from both hemispheres of the brain at once.

Isolated seizures — A single seizure with no risk factors for epilepsy.

Ketogenic diet — A treatment for epilepsy involving high fats, and low carbs. Most often recommended for children with a generalised epilepsy that has failed to respond to medication.

MRI (magnetic resonance imaging) — An imaging technique for getting pictures of the inside of the body without using x-rays.

Myoclonic seizure — A seizure characterised by sudden but brief movements on both sides of the body, most often in the arms and shoulders.

Neurologist — A doctor who specialises in epilepsy and other disorders of the brain and nervous system.

Nocturnal seizure — A seizure that occurs at night during sleep.

Partial seizure — See focal seizure. a seizure that occurs in a specific part of the brain and does not travel to other parts.

Petit mal — An older term for absence seizure. 

Seizure — Altered brain function as a result of abnormal electrical discharges in the brain, often causing changes in behaviour or motor function.

Seizure focus — The part of the brain where a seizure started.

Tonic seizure — Seizures characterised by stiff muscles and abnormal electrical activity on both sides of the brain.

Tonic-clonic seizure — See grand-mal seizure. A type of seizure marked by sudden loss of consciousness, body stiffness, and sudden muscle movements.

Unknown onset seizure — A seizure that cannot be diagnosed as focal or generalised.