How Are Seizures Classified?

The words your doctor uses to name your child's seizure may feel unfamiliar at first: "focal," "generalized," "absence," "tonic-clonic"... This chapter maps out those words. Knowing the seizure type correctly is not just academic curiosity; the right choice of medication depends directly on the seizure type. A medicine that is a miracle for one seizure type can make another seizure type worse.

Why Is the Classification Constantly Updated?

The International League Against Epilepsy (ILAE) develops a common language for classifying seizures. This language is updated as science advances. The classification published in 2017 replaced the older system used for many years, and it was revised in 2025 to make it even clearer. Your doctor uses this current system. Don't worry; you do not have to memorize these fine details. What matters is that you grasp the basic logic.

The First and Most Important Question: Where in the Brain Does the Seizure Start?

At the heart of the modern classification is a single question: Does the seizure start in one region of the brain, or in both halves at the same time? The answer divides seizures into three main groups:

• Seizure Group
• Where Does It Start?
• In Brief
• Focal onset
• In a specific region of one half of the brain
• Starts at one point, sometimes spreads
• Generalized onset
• In both halves of the brain at the same time
• Widespread from the beginning
• Unknown onset
• The starting point cannot be determined
• For example, seizures that occur during sleep, with no witness

A seizure may start out focal and then spread to the whole brain; this is called a focal to bilateral tonic-clonic seizure (formerly known as "secondary generalized"). These distinctions guide your doctor in the treatment plan.

The Second Question: Is Awareness Preserved?

Especially in focal seizures, the second important criterion is the child's state of consciousness/awareness during the seizure — that is, the ability to perceive what is happening around them and respond to it. In this book, we'll simply call this ability "awareness." If the child perceives their surroundings and can respond throughout the seizure, it is called a seizure with preserved awareness; if this ability is impaired, it is called a seizure with impaired awareness. This is also closely related to whether the child later remembers that moment. The current ILAE 2025 classification uses this criterion in the same way.

The Third Question: Is There Visible Movement?

Seizures are also divided into two according to their observable signs. In seizures with movement (motor seizures), there are signs such as stiffening, jerking, thrashing, becoming rigid, or falling. In seizures without movement (non-motor seizures), very little is visible from the outside: zoning out, a blank stare, a change in a sense (smell, taste, sight), a sudden fear, or a strange "inner" feeling. The seizures families most often miss are exactly these vague, movement-free ones.

The Only Thing Asked of You: Being a Good Observer

Your doctor relies on your account to make this classification, because most of the time it is you, not the doctor, who sees the seizure.

Details such as "Did the eyes turn to one side, did the arms stiffen, how long did it last, was the child sleepy afterward?" are the key to the correct diagnosis.

If you can, recording the seizure on video with a cell phone is the most valuable information you can give your doctor.

Old and New Terms: Don't Get Confused

Because the classification has changed over the years, you may hear different terms in different sources or from different doctors. This is not a contradiction, but the result of the terminology being updated. The table below matches commonly encountered old and new terms so that, wherever you come across a term, you'll know what it means.

• Old Term
• Current Equivalent
• Grand mal
• Tonic-clonic seizure
• Petit mal
• Absence seizure
• Partial seizure
• Focal seizure
• Complex partial seizure
• Focal seizure with impaired awareness
• Simple partial seizure
• Focal seizure with preserved awareness
• Secondary generalized seizure
• Focal to bilateral tonic-clonic seizure
• Benign rolandic epilepsy
• SeLECTS (self-limited epilepsy with centrotemporal spikes)

Questions to Help You Tell Seizure Types Apart at Home

You are not a doctor, and you are not expected to make a diagnosis. But the following simple questions will help you give your doctor more useful information and know what to observe:

• Did the seizure start all over the body at once, or in one region? (a clue to the generalized vs. focal distinction)
• Was the child aware of their surroundings throughout the seizure, and did they respond when called? (the awareness distinction)
• Was there any visible movement, or was it only zoning out? (motor vs. non-motor)
• How many seconds/minutes did the seizure last, and how was the child afterward?

Writing the answers to these questions in your seizure diary directly helps your doctor classify the seizure correctly and choose the right medication.