A seizure is a burst of uncontrolled electrical activity between brain cells that causes temporary abnormalities in muscle tone or movements (stiffness, twitching or limpness), behaviors, sensations or states of awareness.

A seizure can be a single event due to an acute cause, such as high fever or medication. When a person has recurring seizures, this is defined as epilepsy.

Seizures symptoms vary and can include a sudden change in awareness or full loss of consciousness, unusual sensations or thoughts, involuntary twitching or stiffness in the body, or severe stiffening and limb shaking with loss of consciousness (a convulsion).

There are two major classes or groups of seizures. Focal onset seizures start in one area and can spread across the brain and cause mild or severe symptoms, depending on how the electrical discharges spread. Generalized seizures can start as focal seizures that spread to both sides of the brain. They also can occur as “generalized onset” seizures in which seizure activity starts simultaneously over both sides of the brain.

Seizures of all kinds are most commonly treated with medication, and, if they are difficult to control, with diet therapy, nerve stimulation or surgery.