A seizure is an electrical disturbance that interferes with normal brain function. It occurs when abnormal electric signals from the brain change the way the body functions. The way that a seizure presents itself can vary a lot between people with epilepsy, depending upon the type of seizures they experience and their particular form of epilepsy.
In order to better understand what is occurring in the brain when a seizure occurs, it is helpful to understand the four distinct phases of a seizure. On this page, you’ll learn about each phase, including what makes them different, when they might occur, and common symptoms that a person with epilepsy might experience.
The four phases of seizure are:
The prodromal phase is a subjective feeling or sensation that can occur several hours or even days before the actual seizure. Prodromal is defined as the period from when early symptoms begin to before the more obvious, diagnosable symptoms begin. The most common symptoms of a prodrome include confusion, anxiety, irritability, headache, tremor, and anger or other mood disturbances.3
About 20% of individuals with epilepsy experience this stage,3 which may serve as a warning sign of seizure onset for those who experience it. Individuals experiencing the prodromal phase may even consider this phase empowering, as they may be warned of an impending seizure.3
Unlike an aura (defined below), this stage is not considered part of the seizure.
For many people with epilepsy, the earliest sign of seizure activity is an aura. Although it has traditionally been thought of as a warning of an oncoming seizure, an aura is the earliest sign of seizure activity and the beginning of the ictal phase.3
The ictal phase includes the time between the beginning (aura, if present) and the end of the seizure.
It is reported that as many as 65% of people with epilepsy experience auras. Much like the prodrome, not everyone with epilepsy has auras, though they are common. For those who do, the specific symptoms vary depending on seizure type, severity, and affected brain region. Some common symptoms include: 4-7
Using the 2017 updated International League Against Epilepsy (ILAE) seizure classification system discussed here, an aura would be called a focal aware seizure. An aura can remain localized or progress to other areas of the brain with the person’s awareness becoming impaired to varying degrees. The aura can also spread to both hemispheres of the brain, becoming a focal to bilateral seizure (formerly called a secondarily generalized seizure) within seconds to minutes after onset. 5, 8
This is the stage of the seizure that most people are familiar with and would identify as a seizure. This stage manifests in different ways for each person with epilepsy. A person may experience a variety of symptoms, including but not limited to: 9
The recovery period following a seizure is called the post-ictal phase. Some people recover immediately, while others may require minutes, hours or days to feel like they’re back at their baseline. The length of the post-ictal stage depends directly on the seizure type, severity, and region of the brain affected. Typical symptoms include: