Absence seizures cause momentary lapses in consciousness. During a seizure, the person may look as though they are daydreaming.
Absence seizures, previously known as petit mal seizures, are a type of epilepsy. They occur due to brief periods of abnormal electrical activity in the brain.
They are most common in children aged 4–14 years, but they can also affect adults.
This article discusses what absence seizures are, how to spot one, and how to treat them.
A seizure refers to a period of abnormal electrical discharge in the brain. There are many types of seizure, and healthcare professionals categorize them by where they start in the brain and their symptoms.
Absence seizures are generalized seizures, meaning that they affect both sides of the brain. This is in contrast with focal seizures, which affect just one area of the brain.
Absence seizures cause a short lapse in awareness. This can involve staring into space and rapid blinking. They start and end quickly, lasting only a few seconds.
There are two subtypes of absence seizures: typical and atypical.
Typical seizures are sudden and last under 10 seconds. Atypical seizures have a slower onset and can last up to 20 seconds or longer.
The seizures can be part of an underlying condition, such as childhood or juvenile absence epilepsy. Receiving a diagnosis of epilepsy typically occurs after experiencing two or more seizures.
Absence seizures cause a momentary lapse in awareness. This can mean that a person will not speak, move, or react to their environment. They may appear to be daydreaming or confused.
The seizure can cause the person to stare blankly into space. Sometimes, their eyelids may flutter, or their eyes may roll upward.
Depending on whether it is a typical or atypical seizure, the episode can last 10 or 20 seconds. Some people barely notice them because they can be so brief.
Atypical seizures have a longer onset and can cause additional symptoms. For example, someone might suddenly start:
- blinking their eyes
- moving their mouth
- smacking their lips
- rubbing their fingers
Absence seizures rarely cause falls.
Following an absence seizure, people typically recover right away. In some cases, however, multiple absence seizures can occur in a row.
Abnormal changes in brain activity cause seizures. Absence seizures are most common in children aged 4–14 years. However, it remains unclear what triggers these changes in brain activity.
In some cases, hyperventilation can trigger an absence seizure. Hyperventilating involves rapidly breathing in and out. This can cause typical absence seizures.
Atypical seizures are less often the result of hyperventilation.
Absence seizures do not always require treatment. However, they can be disruptive to a person’s daily routine when they occur frequently.
A doctor may prescribe medications to treat frequent absence seizures. Common medications for treating absence seizures include:
- valproic acid
- divalproex sodium
Absence seizures typically become less frequent over time. Childhood absence epilepsy and other causes of absence seizures rarely continue into adulthood.
Medication can be effective in preventing absence seizures. Other factors that can help include:
- getting enough sleep
- managing stress
- eating a healthful, balanced diet
- exercising regularly, if possible
Most absence seizures last a few seconds before the person makes an immediate recovery. Some children will experience as many as 50–100 absence seizures in a day.
Although the seizures themselves do not cause any lasting physical damage, experiencing frequent seizures can be disruptive.
Absence seizures cause a short lapse in consciousness. Experiencing multiple seizures throughout the day can be confusing and cause problems at school or when socializing with friends.
Over time, these problems could affect academic performance or social development.
It can take people some time to notice absence seizures. Children may not realize that they are occurring, and parents or caregivers may perceive them as signs of daydreaming or not paying attention.
Providing a comprehensive account of the seizures will help a healthcare professional make a diagnosis. Parents, teachers, and caregivers should try to keep descriptions of what happens before, during, and after a suspected seizure.
Doctors may use an electroencephalogram test to check for unusual patterns in brain activity. They may also use other tests to check for other possible conditions and confirm the diagnosis, including:
- blood tests
- liver and kidney tests
- brain imaging scans, such as MRI scans
- spinal taps
The outlook for absence seizures varies depending on their frequency and severity. In most cases, the child will stop experiencing absence seizures by adulthood.
In other cases, children may require long-term medications to treat their absence seizures. Ongoing treatment can help prevent seizures and reduce their impact on the person’s daily life.
Absence seizures always require a trip to the doctor. However, they can be difficult to detect and may appear to resemble daydreaming.
Look out for the signs of absence seizures that differ from daydreaming, including:
- have a sudden onset
- can occur during movement or other activities
- cannot be interrupted
- last 10–20 seconds
Absence seizures cause brief lapses in consciousness. During an absence seizure, the person may appear to be daydreaming. The symptoms usually last around 10–20 seconds before the person makes an immediate recovery.
Absence seizures are more common in children than adults. They can occur several times per day, which may affect daily life.
There are several medications available that help prevent absence seizures.