Epilepsy Glossary

Absence seizure: A generalized non-convulsive seizure starting abruptly, lasting a few seconds, and ending abruptly without warning or postictal period. The person stops what he/she was doing at the beginning of the seizure and resumes the activity immediately after the end of the seizure, there is no recollection of the episode. This type of seizure is related to a genetic cause.

Ablation: A surgical technique that removes damaged tissues using a laser beam or other heat sources.
Acquired epilepsy: Disease developed due to a specific preceding underlying condition such as brain infection (meningitis), stroke, tumor, or an injury after head trauma. This kind of epilepsy is also called symptomatic-related epilepsy.

Ambulatory EEG: A portable type of EEG recording of the electrical activity of the brain continuously over a period of several hours, usually 24, 48, or 72 hours.
Electrodes are attached to the scalp and connected to a recorder that the person wears on a belt around the waist. This type of EEG can be performed with or without video recording.

Modified Atkins Diet: A special high-fat diet used for difficult-to-treat seizures but less restrictive than the Ketogenic Diet (see below). It allows unlimited amounts of protein foods and fats. Food does not need to be weighed and recipes do not need to be precise. This diet can be used in children, teenagers, and adults.

Alzheimer’s disease (AD): This is the most common form of dementia. AD is a neurologic disease characterized by a loss of mental ability severe enough to interfere with normal activities of daily living, lasting at least six months, and not present from birth. AD usually occurs in the elderly, evidenced by a decline in cognitive functions such as remembering reasoning and planning.

Antipsychotic drugs: A class of medicines used to treat mental illness and emotional conditions.

Brain tumor: A mass inside the brain originated by abnormal growth of brain cells, neurons, or supportive cells.

Congenital malformation (CM): A physical defect present in a newborn that can involve any part of the body including, but not limited to, the brain, heart, lungs, kidneys, intestinal tract, bones, extremities, and face. CM can be genetic or acquired by exposure of the fetus to a malformed agent such as alcohol, drugs, and radiation (X-Rays), particularly during the first trimester of the pregnancy.

Cryptogenic epilepsy: Epilepsy is presumed to have an underlying anatomic cause that remains unidentified.

Dravet syndrome (DS): Also known as Severe Myoclonic Epilepsy of Infancy is a rare and catastrophic form of epilepsy resistant to medical treatment that begins in infancy. The onset of seizures usually begins in the second year of life. Several types of seizures may co-exist in the same child and development remains on track initially but progressive decline typically begins in the second year of life affecting every aspect of daily living. Individuals with Dravet syndrome face a higher incidence of SUDEP.

Dietary supplement: A product intended for ingestion that contains a “dietary ingredient” meant to add further nutritional value to the regular diet. A dietary ingredient may be one or more than one of the following substances: a vitamin, a mineral, an herb, or another botanical.

Epilepsy: A chronic neurological disease characterized by the tendency to have repeated, unprovoked seizures. Its name derives from the Greek word Epibalaneim which means “to seize” or “violent shaking”.

Focal seizure: An older term for partial seizures. A seizure originated on a small focus in the brain.

Food and Drug Administration (FDA): U.S. federal agency responsible for the enforcement of federal regulations on the manufacture and distribution of food, drugs, medical devices, and cosmetics. The regulations are intended to prevent the sale of impure or dangerous substances.

Gamma Knife Surgery: A surgical procedure not actually performed with a knife at all. It is a stereotactic, radioactive, non-invasive (skull is not opened) surgical procedure performed with a device that treats malignant and benign brain tumors, vascular malformations (also known as arteriovenous malformations – AVMs), and other causes of epilepsy.

Generalized seizure: A seizure involving the whole brain and impairment or loss of consciousness results since its onset.

Idiopathic epilepsy: Epilepsy where the cause of the disease is not known but is suspected to be of genetic origin.

Juvenile Myoclonic Epilepsy (JME): Also known as Janz syndrome is a fairly common form of idiopathic generalized epilepsy, representing 5-10 % of all epilepsy cases. The disease typically manifests between the ages of 12 and 18 with brief episodes of involuntary muscle jerks occurring early in the morning. Most patients also have generalized tonic-clonic seizures and absence seizures. The disease is an inherited form of epilepsy.

Ketogenic Diet: Created in 1921, the Ketogenic diet is a medical therapy for children with difficult-to-control epilepsy. This high-fat, moderate protein, very low carbohydrate diet induces a ketotic state (acidosis) that theoretically leads to seizure reduction.

Lennox-Gastaut Syndrome (LGS): This is a severe form of catastrophic epilepsy. Seizures usually begin before 4 years of age and very often, more than one type of seizure co-exists in the same child. These types of seizures include tonic (stiffening of the body, upward deviation of the eyes, altered respiratory pattern), atonic (sudden brief loss of muscle tone and consciousness, causing abrupt falls), atypical absence (staring spells), and myoclonic (sudden muscle jerks). Generalized tonic- clonic and complex partial seizures can also be seen. Children with LGS also experience variable degrees of intellectual disability, developmental delays, and behavioral disturbances. LGS can be caused by brain malformations, perinatal asphyxia, severe head injury, central nervous system infections, and inherited, degenerative, or metabolic causes. In 30-40 percent of cases, no cause is found.

Lyell’s Syndrome: A severe and often fatal cutaneous reaction primarily to drugs but also due to other causes such as infections or cancer, characterized by bulla formation, sub-epidermal separation, and widespread loss of skin leaving raw denuded areas. This disease is considered a more severe form of Stevens- Johnson syndrome.

Magnetoencephalography (MEG): This is a functional neuroimaging technique for mapping brain activity by recording magnetic fields produced by electrical currents occurring normally in the brain. This is a modern diagnostic method to detect abnormal electrical activity in patients with epilepsy and evaluate brain functions for surgical planning in patients with brain tumors or intractable epilepsy.

Neurons: Building blocks of the brain made of a cell body, the axon, and dendrite projections which allow them to communicate with each other.

Partial epilepsy: Epilepsy originating from a part of the cerebral cortex.

Petit Mal: Old medical term for Absence seizures.

Positron Emission Tomography (PET): It is a nuclear, 3-dimensional brain scan that gives information about the function and structure of the brain.

Reflex seizures: These may occur in reflex epilepsy (also known as environmental epilepsy) and they are the result of sensory stimulation caused by the environment such as photosensitivity, noises, odor, and others. The type of stimulus precipitating the seizures defines the type of reflex epilepsy: e.g., photosensitive epilepsy, reading epilepsy, hot water epilepsy, music-induced epilepsy, math epilepsy, and many others.

Responsive Neurostimulation: The Response Neurostimulation System (RNS) is a responsive direct brain stimulation used to treat difficult-to-control seizures in individuals with medically refractory epilepsy. The RNS utilizes a neurostimulator (NeuroPace) implanted in the skull with one or two leads implanted in the brain at the focal points generating the seizures. The neurostimulator monitors the brain’s electrical activity and when the device identifies pre-programmed seizure activity, it attempts to suppress the seizure by sending small electrical stimulation pulses through the leads to that portion of the brain. The device is powered by a long-life battery. The neurologist has a programming device while the patient has a remote monitor to provide information from the stimulator to the neurologist.

Robotic surgery: This is a method to perform surgery using very small surgical tools attached to a robotic arm. The surgeon controls the robotic arm with a computer.

Stevens-Johnson Syndrome: A severe and sometimes fatal inflammatory eruption of the skin, mucous membrane, and viscera, usually affecting children and young adults. It is characterized by the acute onset of fever bullae on the skin and ulcers on the mucous membranes of the lips, eyes, mouth, nasal passage, and genitalia as well as viscera internally. It may be due to an allergic reaction to drugs, infections, or radiation therapy.

Teratogenic effect: The consequences of consuming harmful substances such as alcohol or drugs or exposure to environmental hazards such as X-Rays on a developing fetus causing abnormal growth deficiency (also called congenital malformation) and/or intellectual disability.

West Syndrome: Also known as infantile spasm is a form of catastrophic epilepsy and is characterized by infantile spasms usually beginning in the first year of life, typically between 4 – 8 months of age. The seizures consist of a sudden bending forward of the body with stiffening and hyperextension of the arms and legs.
Spasms tend to occur after awakening or after feeding and often in clusters of up to 100 spasms at a time. Infants may have dozens of clusters per day. West Syndrome usually stops by age 5 but may be replaced by other seizure types and/or evolves into Lennox-Gastaut syndrome.