Understanding Seizure Types
Focal Seizures
A focal seizure involves networks within one side of the brain. What someone experiences depends on which networks are affected and how the seizure develops.
You may encounter older names such as “partial seizures” or “focal-onset seizures.”
About this information
Epilepsy Ontario regularly reviews this educational material. It cannot establish a diagnosis or replace advice, assessment or treatment from a healthcare professional. Speak with your healthcare provider about your own circumstances. Do not change prescribed treatment independently.
Different Experiences
What might happen during a focal seizure?
Some effects are noticeable to other people. Others may only be felt by the person experiencing the seizure.
Movement and behaviour
There may be twitching or jerking in one body part, a pause in activity, or repeated movements such as chewing or picking at clothing.
Sensations and experiences
Someone may notice an unfamiliar smell or taste, tingling, changes in vision, sudden fear or an unusual feeling of familiarity.
Body sensations
Possible experiences include nausea, a rising feeling in the stomach, sweating or changes in heart rate.
Communication
Speech or understanding may be affected. Difficulty speaking alone does not tell you whether consciousness is impaired.
These examples are not a diagnostic checklist. Other health conditions can produce similar symptoms. Repeated or unexplained episodes should be discussed with a healthcare professional.
Understanding the Terms
Consciousness may be preserved or impaired.
The International League Against Epilepsy’s 2025 classification considers both awareness and responsiveness when describing consciousness.
Preserved consciousness
The person remains aware and responsive during the seizure. They may describe sensations that others cannot see.
Older terms include “focal aware” and “simple partial” seizures.
Impaired consciousness
Awareness or responsiveness is affected. The person may look awake but respond differently or have incomplete memory of the episode.
Older terms include “focal impaired awareness,” “complex partial” and “focal dyscognitive” seizures.
What is an aura?
An aura can itself be a focal seizure with preserved consciousness. It may happen on its own or be the first part of a seizure that develops further.
Not everyone experiences an aura, and having one does not reliably predict what will happen next.
Can a focal seizure become convulsive?
Yes. Seizure activity can spread to involve both sides of the brain, producing a focal-to-bilateral tonic-clonic seizure.
Follow the person’s seizure action plan and adapt first aid if the event changes.
First Aid
Stay calm and protect the person.
During the event
- Note the start time and stay nearby.
- Remove hazards and gently guide the person away from danger.
- Speak simply and offer reassurance.
- Avoid restraint and never place anything in their mouth.
- Follow their individual seizure action plan.
During recovery
Allow time for the person to recover. They may need reassurance, rest or help understanding what happened.
Protect their privacy. Do not interpret involuntary behaviour as deliberate refusal to cooperate.
When is emergency help needed?
Call 911 for a first known seizure, one lasting more than five minutes, seizures recurring without recovery, breathing difficulty, serious injury or another emergency sign.
Do not wait five minutes when another emergency sign is present. The full first aid page explains additional circumstances requiring help.
Getting the right assessment
Describe the sequence of symptoms, how long the episode lasted, what the person remembers and how they recovered. A witness’s account may be helpful.
Treatment depends on the diagnosis and individual needs. Ask your healthcare team about ongoing events, new symptoms or concerns about treatment.
Further reading:
ILAE seizure classification
·
Epilepsy Foundation: preserved consciousness
·
Epilepsy Foundation: impaired consciousness.
