What is a seizure?

A seizure is a sudden and temporary change in the electrical and chemical activity in the brain which leads to a change in a person’s movement, behaviour, level of awareness, and/or feelings.

A seizure is a sign that there has been a disruption to the normal functioning of the brain. Seizures can be either provoked or unprovoked. A provoked seizure is caused by a known event such as an illness, flashing lights, stress, or sleep deprivation.

Unprovoked seizures happen without a known cause. For almost 60% of people diagnosed with epilepsy, the cause of their seizures is not immediately known upon diagnosis, and further investigations are needed to determine the underlying cause.

Seizures differ from person to person, and some people experience more than one type of seizure. Depending on the type of seizure, the following things may be experienced:

• A loss of consciousness.
• A range of unusual movements.
• Odd feelings and sensations, such as an unpleasant taste or smell.
• A behaviour change.?
• Loss of bladder control.
• A change in mood.

Every person's experience with seizures is different

For example, some people will still be alert during a seizure and will be able to remember what happened afterwards. Others will be unaware and unable to respond to those around them during a seizure. They may then not remember the seizure at all, or only remember certain aspects before or after the seizure. A person’s level of awareness can vary greatly and depends on the type of seizure being experienced. Following a seizure, the person may feel tired and sleepy, confused, angry, sad or worried. Confusion following a seizure can last several hours, days or sometimes even weeks.

Some people living with epilepsy have seizures every day, while others may only have a seizure occasionally. Some people will notice that their seizures may follow patterns. Some common patterns include nocturnal (nighttime) seizures, although some people even experience seizures at particular times of the day.

Types of seizures

The term ‘motor’ and ‘non-motor’ are often when describing seizure types. Motor relates to physical movement or motion, and seizures involving motor activity may include either an increase or decrease in muscle tone, leading to muscle twitches, jerks or contractions. Non-motor onset seizures don’t involve muscle action but may include behavioural, emotional and/or sensory activity or actions.

Some people experience non-epileptic seizures, which don’t fit into these three categories.

Types of seizures can include:

• Focal onset seizures
• Generalised onset seizures
• Unknown onset seizures
• Psychogenic non-epileptic seizures

If you'd like to learn more about seizures and epilepsy, visit our website.