Understanding Seizures
What is a Seizure?
An epileptic seizure is a temporary event caused by abnormal electrical activity in the brain. It can affect movement, consciousness, sensations, emotions or behaviour.
About this information: This webpage is subject to continuous review by Epilepsy South Central Ontario to help keep the information current. Updates may be in progress. This material is for informational purposes only and should not be used for self-diagnosis or as a substitute for professional medical advice, diagnosis or treatment. Consult your healthcare provider about your own health and care.
Recognizing Differences
What Can a Seizure Look Like?
Seizures do not all look the same. Some involve obvious movements; others involve changes that may be difficult for someone else to notice.
Changes in movement
Examples include stiffening, jerking, repeated movements or a sudden loss of muscle tone. Some seizures affect one part of the body; others involve both sides.
Changes in consciousness
A person may briefly stare, become less responsive or lose consciousness. In other seizures, consciousness remains preserved.
Changes in sensation or emotion
A person may experience unusual sensations, smells, tastes, visual changes or a sudden emotion that others cannot see.
Changes in behaviour
A person may appear confused or make repeated movements, such as picking at clothing. What happens varies with the seizure.
These examples are not a diagnostic checklist. Similar experiences can have other causes. A healthcare professional needs to assess a possible seizure.
Understanding the Terms
Seizure Categories
The International League Against Epilepsy’s 2025 classification uses four main classes. Classification is a clinical process, based on available information.
Focal
Seizures involving networks within one side of the brain. They may be further described by whether consciousness is preserved or impaired.
Generalized
Seizures involving networks across both sides of the brain. This class includes absence seizures and several other seizure types.
Unknown whether focal or generalized
Some features can be described, but there is not enough information to determine whether the seizure is focal or generalized.
Unclassified
The clinician considers the event an epileptic seizure, but there is insufficient information to classify it further.
You may encounter older terms in records or educational materials. Ask your healthcare provider to explain which terms apply to your seizures.
What Happens After a Seizure?
Recovery varies. Some people recover quickly, while others experience confusion, tiredness, headache or temporary weakness. The effects and recovery time depend on the person and the seizure.
Stay with the person and offer calm reassurance as they recover. Follow their seizure action plan, if available.
Important Facts to Remember
- Having a seizure does not automatically mean someone has epilepsy.
- Not every seizure involves convulsions or loss of consciousness.
- Seizures can require urgent medical care. Do not assume every seizure will end safely without help.
- Some people have prescribed rescue medication. It must be used according to their individual instructions and appropriate training.
Know How to Help
Seizure First Aid
Stay calm, time the seizure and help protect the person from injury. Do not restrain them or put objects in their mouth.
Call 911 for a first seizure, a seizure lasting more than five minutes, repeated seizures without recovery, difficulty breathing or another medical emergency. Other circumstances also require emergency help; see the full first aid guidance.
Classification reference:
ILAE: Updated Classification of Epileptic Seizures (2025).