The Epilepsy Center

Epilepsy Glossary


Absence seizures (petit mal): This type of seizure typically occurs in childhood and is distinguishable by short periods ( 5-15 seconds) of staring, blinking, rolling of the eyes, or arm movements. These brief lapses of consciousness are followed by a return to full awareness.

Antiepileptic drugs (AEDs): A category of drugs that can help control the frequency and severity of seizures; they also are known as anticonvulsants. There are several AEDs available; each works in different ways and has proven effective for certain types of epilepsy.

Aura: An unusual physical sensation that occurs in some people before a seizure occurs. Auras, which vary depending on the individual, can be a strange taste or odor, a tense feeling, or even a sound.

Breakthrough seizures: Seizures that periodically occur in a person whose epilepsy is otherwise well controlled.

Brain stem: Located at the front of the cerebellum, it links the cerebrum to the spinal cord and controls various automatic as well as motor functions. It is composed of the medulla oblongata, the pons, the midbrain, and the reticular formation.

Cerebellum: Located at the back of the brain, the cerebellum controls body movement, i.e., balance, walking, etc.

Cerebrum: The brain's largest section can be divided into two parts: the left and right cerebral hemispheres. These hemispheres are joined by the corpus callosum, which enables "messages" to be delivered between the two halves. The right side of the brain controls the left side of the body, and vice versa. Each hemisphere also has four lobes that are responsible for different functions: frontal (behavior, emotions, problem solving); temporal (short-term memory, identification of sound and smell); parietal (touch, language comprehension), and occipital (visual processing, shape and color identification).

Complex partial seizures (psychomotor or temporal lobe epilepsy): This type of seizure affects consciousness and originates from the temporal lobes of the brain. Complex partial seizures are characterized by automatisms, which are involuntary, repetitive behaviors such as head turning and random movement that is not remembered by the person after the seizure is over.

Continuous Video EEG Monitoring: When a longer EEG study is required, patients stay in a special unit in the hospital for at least 24 hours. In the unit, a video camera connected to the EEG provides constant monitoring, enabling the medical team to pinpoint the area where a seizure occurs and track the patient's physiological response to the seizure.

Cranial nerves: Twelve pairs of nerves responsible for various functions, including speech, hearing, taste, facial sensation and facial expression, balance, and smell.

Cranium: The bony covering that surrounds the brain. The cranium and the facial bones comprise the skull.

Electroencephalogram (EEG): During this non-invasive test, several electrodes are placed on a patient's scalp. They record electrical impulses from the brain known as brain waves.

"Eloquent" brain: Areas within the brain that control the senses, motor functions, and speech.

Functional Image Guided Surgery(FIGS):A combination of Functional MRI with frameless stereotactic surgery that creates a precise, detailed "road map" for the surgeon to follow during an operation

Frontal lobe: One of the brain's four lobes, the frontal lobe is where such functions as speech, emotions, and reasoning originate. As the name suggests, it is located at the front of the brain.

Functional MRI: With Functional MRI, a map of the brain can be created that indicates where language, motor, and sensory areas are located. An imaging technique that incorporates "real time" sequence, it is also faster than traditional magnetic resonance imaging.

Generalized seizures: Seizures that originate in several parts of the brain.

Hypothalamus: The part of the brain that acts as a messenger to the pituitary gland; it also plays an integral role in body temperature, sleep, appetite, and sexual behavior.

Intractable epilepsy: A form of epilepsy that does not improve (fewer or less severe seizures) with medication. Surgery may be the next recommended course of treatment to improve the patient's condition.

Ketogenic diet: This special high-fat, low carbohydrate diet is sometimes recommended for children with intractable epilepsy. It is carefully designed to help the patient's body make large amounts of ketones, which are produced when fats are processed in the liver. The diet helps reduce the number of seizures in some patients, although precisely why this beneficial effect occurs is not known.

Left hemisphere: The half of the cerebrum sometimes referred to as the "dominant" hemisphere. It has primary responsibility for speech and language. However, in some left-handed people, the right hemisphere controls speech function.

Medulla oblongata: This section of the brain stem connects the brain to the spinal cord. It is responsible for involuntary functions such as breathing, heart rhythms, and swallowing.

Meninges: Protective layers of tissue that surround the brain and the spinal cord.

Midbrain: Part of the brain stem, it is the origin of the third and fourth cranial nerves, which control eye movement and eyelid opening.

Neuropsychological testing: A patient's cognitive abilities, memory, and motor skills are assessed through a variety of tests.

Occipital lobe: This lobe is located at the back of the brain and controls many visual functions.

Optic chiasm: The area in the front of the brain where the optic nerves cross.

Parietal lobe: This lobe is associated with perception of stimuli such as pain and touch.

Partial seizures: Seizures that begin in one part of the brain.

Pons: This part of the brain stem is the origin of four pairs of cranial nerves: fifth (facial sensation); sixth (eye movement); seventh (taste, facial expression, eyelid closure); and eighth (hearing and balance).

Posterior fossa: The part of the skull containing the brain stem and the cerebellum.

Right hemisphere: The half of the cerebrum that processes visual information.

Seizure focus: The area(s) of the brain where seizures originate.

Simple partial seizures: These seizures generally do not affect consciousness and are the most common type of epilepsy. They may cause sudden, jerking motions of the body and affect vision or hearing.

Single Photon Emission Computed Tomography (SPECT): A scanner that measures a low-dose radioactive material as it circulates through the brain. SPECT can track cerebral blood flow and detect alternations in brain metabolism between and during seizures.

Status epilepticus: Repeated convulsions that occur without a break of consciousness between them. This is a medical emergency that can result in permanent brain damage.

Temporal lobe: This lobe is associated with memory, hearing, and perception.

Thalamus: A small area in the brain that relays information to and from the cortex and translates impulses related to pain, attention, and alertness.

Tonic-clonic seizures (grand mal): These seizures are characterized by a stiffening of the body and jerking body movements. A person sometimes loses consciousness during a tonic clonic seizure and may also have shallow breathing and a loss of bowel/bladder control.

Triggers: In some people, certain factors that seem to bring on or "trigger" a seizure. Among the most common triggers are: lack of sleep; flashing lights; alcohol; smoking; the hormonal changes brought on by the menstrual cycle; and stress

Vagal Nerve Stimulator: A small, battery-operated device that sends low levels of electrical current to the left vagal nerve. This nerve sends messages to the area of the brain believed to be responsible for producing seizures. The vagal nerve stimulator is implanted in the patient's body, much like a pacemaker.

Ventricles: Four small cavities within the brain, they contain the choroid plexus, which produce cerebrospinal fluid.

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