Absence seizure: A short seizure (less than 20 seconds) that can cause one to stare or blink repeatedly or make some type of repeated hand movement. This type of seizure is common in children with epilepsy.

Aura: A distinct sensation or automatic movement right before a generalized seizure. Examples of auras include strange sensations of smell, light and sound. A person may also experience déjà vu, which is a feeling of already having experienced something.

Clonic seizure: A seizure that causes jerking movements in one part or all of the body.

Epilepsy: A medical condition of the brain characterized by recurrent seizures that may include repetitive muscle jerking called convulsions.

Generalized seizure: A seizure that involves the entire brain.

Myoclonic seizure: A quick muscle jerk caused by abnormal electrical activity in one part of the brain.

Neuron: Any of the impulse-conducting cells that constitute the brain, spinal column, and nerves, consisting of a nucleated cell body with one or more dendrites and a single axon. Also called a nerve cell.

Partial seizure: A seizure that involves only one part of the brain.

Seizure: A condition that is caused by too much electrical activity in brain cells (neurons).

Tonic seizure: A seizure that causes the muscles to go stiff on both sides of the body.