What are absence seizures?
What are absence seizures?Absence seizures are generalised onset seizures, which means the seizure affects both hemispheres (sides) of the brain from the onset. Because of this, a person may lose awareness at the start of the seizure.
The most common absence seizure is the typical absence seizure. These are generally easy to diagnose with a routine EEG as they can be provoked with hyperventilation (fast deep breaths) and show a specific waveform on EEG.
Absence seizures usually begin in childhood (but can occur in adolescents and adults) and are easily missed or mistaken as daydreaming, inattentiveness or “not listening”. They are so brief, they can be easily missed and often are not diagnosed until the child starts school where he or she must be more attentive, making these lapses in concentration more obvious. If not treated, they can interfere with school and learning.
What do they look like?
Typically, an absence seizure will look like:
- the seizure starts suddenly, and the person stops what they are doing
- they will stare vacantly, with loss of facial expression and unresponsiveness
- sometimes eye blinking, upward eye movements, or small movements of the hands are seen
- the seizure can last from two to 20 seconds and start and end abruptly
- straight after the seizure the person is wide awake, resumes their previous activity, usually unaware the seizure has happened or no memory of what happened during the seizure
What can trigger absence seizures?
The triggers for absence seizures are usually the same as for other types of epilepsy. They include:
- Lack of sleep
- Not taking medications as prescribed
- Emotional stress, worry or excitement
- Breathing heavily, hyperventilation
- Flashing lights, bright sunlight
- Use of alcohol or other drugs.
Treatment
These seizures can happen many times a day which can affect learning or daily activities. They generally respond well to medication. Problems with attention may continue despite controlling the seizures.
Many children outgrow absence seizures in their teenage years. In these cases, antiseizure medications can usually be weaned. However, some children may develop other seizure types.
Is it an absence seizure?
Visually, absence seizures can be difficult to recognise as seizures, and sometimes diagnosis is delayed because they are mistaken for daydreaming or behaviour.
However, some people refer to their seizures as absence seizures when in fact, they may be another seizure type. You may not be having a typical absence seizure if your seizures:
- Start slowly or you have a warning of an impending seizure
- absence seizures start and end suddenly
- Last longer than 45 seconds
- absence seizures are very brief, usually less than 30 seconds
- Have a period of confusion afterwards
- there is no confusion seen after an absence seizure
Speak to your doctor or contact us on 1300 37 45 37 or email [email protected] for further information.
References:
Cleveland Clinic. Absence Seizures. Accessed 23 May 2022. https://my.clevelandclinic.org/health/diseases/22194-absence-seizures
EpilepsyDiagnosis ILAE. Typical Absence Seizures. Accessed 23 May 2022. https://www.epilepsydiagnosis.org/seizure/absence-typical-overview.html
Epilepsy Foundation USA. Childhood Absence Epilepsy. Accessed 23 May 2022. https://www.epilepsy.com/what-is-epilepsy/syndromes/childhood-absence-epilepsy
