2017 Revised Classification of Seizures

The International League against Epilepsy (ILAE) is the world's main scientific body devoted to the study of epilepsy, and it has recently revised its classification of seizures. The changes will help make diagnosing and classifying seizures more accurate and easier. In this article, you'll find the new general outline and basic seizure classification. In the coming weeks, epilepsy.com will be updated to reflect the new classification to help users searching for both the older and newer terms.

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  • Atonic means an abrupt loss of muscle tone.
  • They are also known as drop attacks.
  • In some children, only their head suddenly drops.

What is an atonic seizure?

Muscle "tone" is the muscle's normal tension. "Atonic" (a-TON-ik) means "without tone," so in an atonic seizure, muscles suddenly lose strength. The eyelids may droop, the head may nod, and the person may drop things and often falls to the ground. These seizures are also called "drop attacks" or "drop seizures." The person usually remains conscious. These seizures typically last less than 15 seconds. They often start in childhood yet last into adulthood. Many people with atonic seizures are injured when they fall, so they may choose to use protection such as a helmet.

Another name for this type of seizure is "akinetic" (a-kin-ET-ik), which means "without movement."

Who is at risk for atonic seizures?

Atonic seizures usually begin in childhood and are often seen in syndromes like Lennox Gastaut syndrome.

What’s it like to have an atonic seizure?

In an atonic seizure, the person's body will get limp. If sitting, their head or upper body may slump over. If standing, the person many fall limply to the ground. People who have seizures that cause them to fall rigidly (like a tree trunk) often have tonic seizures (involving sudden muscle contraction) rather than atonic seizures.

What happens after an atonic seizure?

When an atonic seizure ends, the person may or may not be confused. Because these seizures often results in falls, first aid may be necessary especially if the seizure led to an injury or bruise. Helmets are often recommended for patients who have this type of seizure.

If someone has atonic seizures, how often will they occur?

It depends. Patients who have this type of seizure may have one or several in a row. When an atonic seizure occurs, make sure the person is in a safe place to prevent injuries from a fall.

How can I tell if someone is having an atonic seizure?

These seizures tend to be fairly obvious because the person if standing may suddenly drop and fall to the ground. Other times, the person if sitting may appear to have their head suddenly droop down.

How are atonic seizures diagnosed?

Usually descriptions of the seizures by witnesses will suggest the diagnosis. Some EEG monitoring may be performed to confirm it. If the seizures persist, other tests may be used to make sure that changes in the heart rhythm or blood pressure are not causing the patient to fall down.

How are atonic seizures treated?

There are medicines, devices (Vagus nerve stimulator) , diet ( ketogenic or modified Atkins) and even surgeries (callosotomy) that can help prevent atonic seizures.

What should I do if I think my child or loved one may have atonic seizures?

If you think your child, loved one or yourself may be having atonic seizures, it is important to talk to your doctor right away. These seizures have the potential to cause serious injury due to falls. Getting an appropriate diagnosis and treatment is essential.

Authored by: Joseph I. Sirven, MD | Joan Sirven | Orrin Devinsky, MD on 7/2013
Reviewed by: Joseph I. Sirven, MD | Patricia O. Shafer, RN, MN on 3/2014
What It Looks Like...

When Bob has a 'drop' seizure, he falls to the ground and often hits his head and bruises his body. Even if I'm right next to him and prepared, I may not catch him. Even with carpet in the bedroom and mats in the bathroom, he gets hurt.