How are seizures classified now?

The new terms consider these important areas when describing seizures.

1. The onset or beginning of a seizure: Where seizures start in the brain tells a lot about what may occur during a seizure, what other conditions or symptoms may be seen, how they may affect someone and, most importantly, what treatment may be best for that

2. A person’s level of awareness during a seizure: Whether a person is aware or not tells a lot about the type of seizure. It’s also very important to know for a person’s safety.

3. Whether movements happen during a seizure: Seizures can also be described by whether motor symptoms occur. When no motor symptoms happen, it can be called a non-motor seizure. This level of description does not need to be used all the time, especially when generally describing or talking about seizures. Yet other times you may find the motor terms helpful.

There are now 3 major groups of seizures.

These seizures affect both sides of the brain or groups of cells on both sides of the brain at the same time. This term was used before and still includes seizures types like tonic-clonic, absence, or atonic to name a few.

The term focal is used instead of partial to be more accurate when talking about where seizures begin. Focal seizures can start in one area or group of cells in one side of the brain.

  • Focal Onset Aware Seizures: When a person is awake and aware during a seizure, it’s called a focal aware seizure. This used to be called a simple partial seizure.
  • Focal Onset Impaired Awareness: When a person is confused or their awareness is affected in some way during a focal seizure, it’s called a focal impaired awareness seizure. This used to be called a complex partial seizure.

When the beginning of a seizure is not known, it’s now called an unknown onset seizure. A seizure could also be called an unknown onset if it’s not witnessed or seen by anyone, for example when seizures happen at night or in a person who lives alone.

  • As more information is learned, an unknown onset seizure may later be diagnosed as a focal or generalized seizure.

How are different symptoms during a seizure described?

Many different symptoms happen during a seizure. This new classification separates them simply into groups that involve movement.

  • Motor symptoms may include sustained rhythmical jerking movements (clonic), muscles becoming weak or limp (atonic), muscles becoming tense or rigid (tonic), brief muscle twitching (myoclonus), or epileptic spasms (body flexes and extends repeatedly).
  • Non-motor symptoms are usually called absence seizures. These can be typical or atypical absence seizures (staring spells). Absence seizures can also have brief twitches (myoclonus) that can affect a specific part of the body or just the eyelids.
  • Motor symptoms may also include jerking (clonic), muscles becoming limp or weak (atonic), tense or rigid muscles (tonic), brief muscle twitching (myoclonus), or epileptic spasms. There may also be automatisms or repeated automatic movements, like clapping or rubbing of hands, lipsmacking or chewing, or running.
  • Non-motor symptoms: Examples of symptoms that don’t affect movement could be changes in sensation, emotions, thinking or cognition, autonomic functions (such as gastrointestinal sensations, waves of heat or cold, goosebumps, heart racing, etc.), or lack of movement (called behavior arrest).
  • Motor seizures are described as either tonic-clonic or epileptic spasms.
  • Non-motor seizures usually include a behavior arrest. This means that movement stops – the person may just stare and not make any other movements.