Atonic Seizure

What is an atonic seizure?

An atonic seizure is a burst of electrical activity in your brain that causes you to lose muscle control and tone. You may close your eyes, drop what you’re holding or fall down. Injuries are common during atonic seizures.

Think about a puppet — a doll held upright by strings. The doll doesn’t have anything to support its body to stand up unless you pull on the strings. If you loosen the puppet’s strings, it slumps over. When you pull the puppet’s strings again, it stands back up.

An atonic seizure happens when the strings on the puppet loosen. You lose muscle tone and can’t support your body. As soon as the seizure ends, your muscle control returns and you can stand up and move as expected.

You may hear your healthcare provider refer to atonic seizures as:

• Akinetic seizures.
• Drop seizures.
• Drop attacks.

Your healthcare provider can help you take precautions and stay safe if you have repeat atonic seizures.

What are the symptoms of an atonic seizure?

The symptoms of atonic seizures include a sudden and temporary loss of:

• Muscle tone in part or all of your body (limp and weak muscles).
• Consciousness (awareness).

After an atonic seizure, your muscle tone will return.

Are atonic seizures dangerous?

Injuries are very common with atonic seizures. They may cause you to fall down, close your eyes or drop what you’re holding. You may be doing something seemingly safe when you suddenly lose muscle control. This may lead to:

• Cuts and lacerations.
• Bruises.
• Broken bones.
• Traumatic brain injury.

Activities like driving or operating heavy machinery may be extremely dangerous if you have a seizure. Losing focus on a task that requires your full attention, even for just a moment, may lead to life-threatening outcomes.

How long do atonic seizures last?

Atonic seizures usually last around 15 seconds. After a seizure, you might be confused, but often, there is a quick recovery, and you’ll be able to resume your activity.

In some cases, seizures can happen back-to-back. These seizure clusters may make it look like you’re paralyzed for several minutes to hours. Back-to-back seizures that last longer than 15 minutes are a medical emergency.

Atonic seizure after-effects

After an atonic seizure, your muscle strength will return. In some cases, you may not be able to move for several seconds (paralysis) after the seizure ends.

You may feel confused about what just happened. You’ll likely come to in a different position than how you were a moment ago. For example, if you were standing up before the seizure, you may find yourself on the ground when you regain awareness. You may need some time to rest, especially if you injured yourself.

Many children don’t feel bothered after an atonic seizure if they’re uninjured. They may continue the activity that they were doing before the seizure as soon as they regain muscle tone.

What causes an atonic seizure?

A surge of electrical activity in areas of your brain that regulate your muscle tone, like your frontal lobe and brainstem, causes an atonic seizure. The reason why this happens is unknown.

What are the risk factors for an atonic seizure?

You may be more at risk of atonic seizures if you:

• Are younger than 18 years of age.
• Have a history of seizures during infancy (infantile spasms).
• Have an underlying condition like Lennox-Gastaut syndrome or Dravet syndrome.

Some atonic seizures may last into adulthood, but it’s less common to receive a diagnosis as an adult.

How is an atonic seizure diagnosed?

A healthcare provider will diagnose an atonic seizure after a physical exam, neurological exam and testing. During the exams, your provider will learn more about your seizure symptoms. It helps to have a loved one who witnessed the seizure with you during the exam (or have them write down what they noticed if they can’t be there) so your provider better understands what happened. Cell phone videos of the seizures can also be helpful.

Testing can help your provider diagnose seizures or rule out conditions or causes of a sudden loss in muscle tone and consciousness. Testing may include:

• Blood tests.
• Electroencephalogram (EEG).
• Magnetic resonance imaging (MRI).
• Positron emission tomography (PET) scan.

If you had an injury after the seizure, a healthcare provider may run additional testing, like an X-ray, to see if you have any broken bones, for example.

How is an atonic seizure treated?

A healthcare provider may treat atonic seizures with antiseizure medications like:

• Benzodiazepines (clonazepam or clobazam).
• Felbamate.
• Levetiracetam.
• Topiramate.
• Valproic acid (valproate).
• Zonisamide.

If an injury occurred during the seizure, your provider will treat that immediately.

Your provider may consider other types of treatment if antiseizure medications aren’t successful or you had many seizures with significant injuries. These may include:

• Surgery (corpus callosotomy).
• Vagus nerve stimulation.
• Wearing protective headgear.

In some cases, your doctor may suggest a specialized medical diet like the ketogenic diet, which can be helpful in managing seizures.

What’s the outlook for an atonic seizure?

Your healthcare provider will give you the best information about your outlook, as they vary from person to person. Antiseizure medications and other types of treatment may reduce how often you have seizures. Injuries that happen during a drop seizure may affect your outlook. Your provider may offer suggestions to prevent future injuries that happen during seizures.

When should I see a healthcare provider?

Contact a healthcare provider if you have more frequent atonic seizures or you’re injuring yourself more often. A healthcare provider may adjust your treatment plan to keep you safe.

When should I go to the ER?

Visit the emergency room or contact emergency services if you:

• Have a seizure for the first time.
• Severely injure yourself during a seizure (like breaking a bone).
• Have several seizures back-to-back (more than three seizures in 30 minutes).

What questions should I ask my healthcare provider?

If you have atonic seizures, you may want to ask your provider:

• What type of treatment do you recommend?
• Are there side effects of the treatment?
• Can I drive?
• What activities are safe to do?

What’s the difference: Atonic vs. tonic seizures?

The main difference between atonic and tonic seizures is what happens to your muscles during a surge of electrical activity in your brain:

• Atonic: Your muscles weaken.
• Tonic: Your muscles tighten.

You may collapse or slump over during an atonic seizure. You may fall like a tree being chopped down during a tonic seizure. Convulsions don’t usually happen with atonic seizures but you may lose consciousness.