Absence seizure

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at April 21, 2016
StartDiseasesAbsence seizure

An absence seizure is a seizure that causes the afflicted person to stare into space and project a vacant look. It gets its name due to the fact that the person is awake and his or her eyes are open, but he or she is unresponsive. Absence seizures are sometimes also called a petit mal seizure.


Definition & Facts

An absence seizure may appear as though a person is daydreaming. However, inside the brain, the electric activity is abnormal. The absence seizure is one of six types of seizures categorized as generalized epilepsy. Since absence seizures are considered to be part of epilepsy, a person displaying absence seizures can also display the other five types of epileptic seizures too.

Absence seizures primarily afflict those between the ages of 4 and 12. It is estimated that 4.3 million Americans over the age of 18 have epilepsy, and it costs the US over $15.5 billion yearly.

Symptoms & Complaints

The first visible symptom that comes with absence seizures is a vacant stare. Unlike with grand mal seizures, those experiencing absence seizures do not lose control of their bodily functions. However, it is not uncommon to see a person smack their lips during the seizure. They may also have eyelid flutters, make chewing motions, rub their thumb and forefinger rapidly, and make small movements with their hands. Absence seizures can last up to 20 seconds.

When people have a disruption in their brain activity that causes these absence seizures, someone can try to talk to them, but they will be unable to respond. They may appear alert, but they are unable to hear or communicate. As with any epileptic event, a person with this condition is in danger when operating machinery or driving a car.

Absence seizures can happen at any time or place with no real apparent reason. Some say stress aggravates these episodes, but there is no solid evidence to support that claim. Someone with epilepsy can have 20-30 absent seizures each day.


Absence seizures are caused by a medical condition called epilepsy. Epilepsy is a neurological disorder where the brain short circuits and causes the brainwaves to disrupt. Just like the heart, the brain has electrical components. When those electrical currents are disrupted, it causes seizures. Many different conditions can cause a brain to develop epilepsy including:

It is not uncommon for children to have absence seizures in their youth and then to outgrow the disease by the time they reach adulthood. Absence seizures may be induced by hyperventilation.

Epilepsy affects people differently. One may have frequent grand mal seizures and be unable to work or drive. Another person may be able to live a productive life with only the occasional seizure. The cause of epilepsy in each person will vary, and in some cases there are no real indications what is causing these events. When an adult reaches an advanced age, they can start having seizures due to health problems. The advanced age makes an individual prone to strokes, which is caused by blood clots.

Diagnosis & Tests

The most common test done to confirm the diagnosis of absence seizures is called an EEG. Electrodes are attached to the scalp, for a period of time, to monitor brain activity. The test does not hurt and is fairly simple. The goal is to capture an episode while using the machine. Some doctors will stimulate seizure activity using lights and encouraging the patient to hyperventilate.

In some cases, a person may be having pseudo-seizures. These seizures are psychiatric in nature and are not caused by epilepsy. There are several types of seizures that a person can have. The doctor will place the diagnosis of epilepsy into two categories: generalized epilepsy or partial epilepsy. The two are distinguished between how and where they begin. Absence seizures fall under the generalized category.

Treatment & Therapy

After a definitive diagnosis has been made, the doctor will want to find the underlying cause. Often by classifying the seizure it can help identify its origins. If there is swelling on the brain, the goal is to figure out what is causing the swelling and to reduce it. If there has been a stroke, they may consider surgical options to restore blood flow to the injured area of the brain.

For most people, the way to control their absence seizures and epilepsy is through medications. Ethosuximide and valproic acid are anticonvulsant drugs approved by the FDA for treating absence seizures. The latter is also used in the treatment of bipolar disorder.

Medications work for some, diet for others, and then there are those who have a device implanted into their brain. This little device, known as a vagus nerve stimulator, is similar to having a pacemaker in the brain. When the brain starts to short-circuit and go into seizure mode, the VNS machine sends pulses of electric stimulation to control the seizure.

Prevention & Prophylaxis

Absence seizures can be prevented with the use of medications. Because epilepsy is sometimes caused by head trauma, it is advisable to wear proper safety gear when engaging in sports or activities that may cause brain injuries.