What Is an Atonic Seizure? Symptoms, Causes, and Treatment
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer: What is an atonic seizure and is it serious?
An atonic seizure is a brief seizure in which electrical surges in the brain make the muscles go limp, causing sudden drop attacks and falls that often cause injuries. [1] Episodes last less than 15 seconds and recovery is usually quick [1], but severe injuries or seizure clusters lasting over 15 minutes need emergency care. [7] Medications and safety strategies help most people.
Key takeaways
Atonic seizures cause a sudden loss of muscle tone and brief loss of awareness, often resulting in a fall. [7]
Episodes typically last less than 15 seconds, and muscle control returns quickly once the seizure ends. [1]
Injuries are very common: falls can cause cuts, bruises, broken bones, and traumatic brain injury. [7]
It usually begins in childhood; the condition is often linked to Lennox-Gastaut or Dravet syndrome. [1] [7]
Treatment includes antiseizure medications, protective headgear, the ketogenic diet, vagus nerve stimulation, and sometimes surgery. [1]
Go to the ER for a first-time seizure, a severe injury, or more than three seizures within 30 minutes. [7]
What the research says
Drop attacks are among the hardest seizures to control, and treatment choices vary. In a survey of 71 pediatric neurologists in Saudi Arabia, 77% used valproic acid as a first-line drug for epileptic drop attacks, and levetiracetam, clobazam, topiramate, and rufinamide were also part of initial treatment plans. The authors describe these seizures as one of the most drug-resistant types and call for evidence-based guidelines. (Alhiniah et al., Neurosciences (Riyadh), 2023) [4]
No single drug has been shown to work well for every drop seizure. A Cochrane review of nine randomized trials in Lennox-Gastaut syndrome, a common cause of drop seizures, could not pool the results because the trials were so different. It concluded that no drug has been shown to be highly effective, that rufinamide, lamotrigine, topiramate, and felbamate may help as add-ons, and that clobazam may help with drop seizures. (Hancock & Cross, Cochrane Database Syst Rev, 2013) [5]
Newer medicines made for Lennox-Gastaut syndrome can reduce drop seizures further. In a double-blind trial of 225 patients aged 2 to 55 years, the median drop in drop-seizure frequency was 41.9% with cannabidiol at 20 mg/kg, 37.2% at 10 mg/kg, and 17.2% with placebo. Side effects included sleepiness, decreased appetite, diarrhea, and raised liver enzymes in 9% of treated patients. (Devinsky et al., N Engl J Med, 2018) [6]
What Is an Atonic Seizure?
An atonic seizure is a temporary loss of consciousness and muscle control caused by an abnormal burst of electrical activity in the brain. During an episode, a person may close their eyes, drop what they are holding, or fall down. Injuries are common during these seizures. [7]
A helpful way to picture it is a puppet held upright by strings. Pull the strings and the puppet stands; loosen them and it slumps over. An atonic seizure is like the puppet's strings loosening: muscle tone vanishes and the body can no longer support itself. As soon as the seizure ends, the "strings" tighten again, muscle control returns, and the person can stand and move as expected.
You may hear this seizure type called by other names: akinetic seizures, drop seizures, or drop attacks. [7] They all describe the same event.
What Are the Symptoms of an Atonic Seizure?
The defining symptoms are a sudden, temporary loss of muscle tone, in part or all of the body, leaving muscles limp and weak, and a sudden, temporary loss of consciousness, or awareness. [1] After the seizure, muscle tone returns.
Symptom | What happens |
Loss of muscle tone | Muscles in part or all of the body go limp and weak |
Loss of consciousness | Brief loss of awareness |
Falling | Many people fall down because they cannot brace themselves |
Dropping objects | Whatever the person was holding is dropped |
Eyes closing | Many people close their eyes during the episode |
Why Are Atonic Seizures Dangerous?
Injuries are very common with atonic seizures. [7] A person may fall down, close their eyes, or drop what they are holding, often while doing something that seemed perfectly safe.
Possible injury | How it happens |
Cuts and lacerations | Hitting sharp surfaces or objects during a fall |
Bruises | Impact with the floor or furniture |
Broken bones | Unprotected falls onto hard surfaces |
Traumatic brain injury | Head impact when falling without warning |
Certain activities become extremely dangerous with this seizure type. Driving or operating heavy machinery is risky because losing focus for even a moment can lead to life-threatening outcomes. [7]
How Long Do Atonic Seizures Last?
Atonic seizures usually last less than 15 seconds. [1] Afterward, you might feel confused for a short time, but recovery is often quick and you can usually resume your activity. [1]
Sometimes seizures happen back-to-back. These seizure clusters can make it look like the person is paralyzed for several minutes or even hours. [7] Back-to-back seizures lasting longer than 15 minutes are a medical emergency. [7] Seek emergency care right away.
What Happens After a Seizure?
Muscle strength returns after the seizure ends. In some cases, a person may not be able to move for several seconds (brief paralysis) before strength comes back. [7]
Confusion about what just happened is common. You may also wake up in a different position than where you started: someone who was standing may find themselves on the ground when awareness returns. Rest may be needed afterward, especially if there was an injury.
Children often take drop seizures in stride. If uninjured, many children don't feel bothered and return to their activity as soon as muscle tone comes back. [7]
What Causes an Atonic Seizure?
A surge of electrical activity in the brain regions that regulate muscle tone, particularly the frontal lobe and the brainstem, causes an atonic seizure. Why this surge happens is unknown. [7]
What Are the Risk Factors?
Atonic seizures mostly begin in childhood, though some continue into adulthood. [1] Adult diagnosis is less common.
Risk factor | Detail |
Age under 18 | Being younger than 18 raises the risk |
History of infantile spasms | Seizures during infancy raise the risk |
An underlying childhood epilepsy syndrome linked to drop seizures | |
Another epilepsy syndrome associated with atonic seizures |
How Is an Atonic Seizure Diagnosed?
A healthcare provider diagnoses an atonic seizure after a physical exam, a neurological exam, and testing. [7] During the exams, the provider learns more about the seizure symptoms.
One tip: bring a loved one who witnessed the seizure to the appointment, or have them write down what they noticed. Cell phone videos of the seizures can also be extremely helpful. [7]
Test | Purpose |
Physical exam | General health and symptom review |
Neurological exam | Assessment of nervous system function and seizure symptoms |
Blood tests | Rule out conditions causing sudden loss of muscle tone and consciousness |
EEG (electroencephalogram) | Measures the brain's electrical activity |
MRI | Images the brain to look for underlying causes |
PET scan | Shows brain activity patterns |
X-ray | Used only if an injury occurred, to check for broken bones |
How Is an Atonic Seizure Treated?
The first line of treatment is antiseizure medication. If an injury occurred during a seizure, a provider treats that immediately as well.
Treatment | When it's used |
Antiseizure medications | First-line treatment to reduce seizures |
Protective headgear | Worn to prevent head injury during falls |
A specialized medical diet that can help manage seizures | |
Considered when medications fall short | |
Surgery (corpus callosotomy) | Considered when medications fail or injuries are significant |
What medications are used?
Common antiseizure medications for atonic seizures include: [7]
Medication | Class or notes |
Clonazepam; clobazam | Benzodiazepines |
Felbamate | Antiseizure medication |
Levetiracetam | Antiseizure medication |
Topiramate | Antiseizure medication |
Valproic acid (valproate) | Antiseizure medication |
Zonisamide | Antiseizure medication |
What Is the Outlook?
Outlook varies from person to person, and a healthcare provider will give the best information for your specific situation. Antiseizure medications and other treatments may reduce how often seizures happen. [7] Injuries that occur during drop seizures can affect the outlook, so your provider may offer suggestions to prevent future injuries.
Living With Atonic Seizures
Atonic vs. tonic seizures: what's the difference?
The key difference is what happens to the muscles during the electrical surge.
Feature | Atonic seizure | Tonic seizure |
Muscles | Weaken and go limp | Tighten and stiffen |
How a person falls | Collapses or slumps over | Falls stiffly, "like a tree being chopped down" |
Convulsions | Usually do not occur | More common |
Consciousness | May be lost | May be lost |
When should I see a healthcare provider?
Contact a healthcare provider if you experience more frequent atonic seizures or if you are injuring yourself more often. A provider may adjust your treatment plan to keep you safe.
When should I go to the ER?
Emergency situation | Why it matters |
First-time seizure | Needs immediate medical evaluation |
Severe injury during a seizure | Such as a broken bone, which needs immediate treatment |
Back-to-back seizures | More than three seizures within 30 minutes is a medical emergency |
Questions to ask your provider
Come prepared to ask: What treatment do you recommend? Are there side effects? Can I drive? Which activities are safe for me?
Conclusion
Atonic seizures are brief, usually less than 15 seconds, but their suddenness is what makes them dangerous. [1] Because muscle tone vanishes without warning, there is no chance to brace for a fall, and injuries like cuts, broken bones, and head trauma are common. [1] The good news is that the condition is manageable: antiseizure medications help many people, and when they fall short, options like the ketogenic diet, vagus nerve stimulation, protective headgear, and surgery can reduce seizures and protect against injury. [7] If you or someone you care about has experienced sudden falls with brief loss of awareness, a medical evaluation is the essential first step: an accurate diagnosis unlocks the right treatment plan and the right safety precautions. [1]
Take the next step in understanding your health. For families managing seizure disorders, visual guides help caregivers remember emergency first-aid steps, warning signs, and daily safety routines. Rinnit's library of health infographic templates can help you create simple, shareable visuals for your family's care journey.
Frequently Asked Questions
What does an atonic seizure look like?
A person's muscles suddenly go limp and they briefly lose awareness. They may slump over, close their eyes, drop what they are holding, or fall down without warning. The episode typically lasts less than 15 seconds, and muscle control returns afterward. [1]
Why are they called drop seizures?
Because the sudden loss of muscle tone makes the person "drop," collapsing or slumping to the ground without being able to brace themselves. "Drop attacks" and "akinetic seizures" are other names for the same seizure type. [7]
Are atonic seizures dangerous?
The seizure itself is brief, but the fall is risky. Injuries are very common, including cuts, bruises, broken bones, and traumatic brain injury. Driving and operating heavy machinery are especially dangerous with this seizure type. [7]
How long does an atonic seizure last?
Usually less than 15 seconds. [1] Recovery is often quick, though some confusion is common afterward, and in rare cases brief paralysis may follow the episode. Clusters of back-to-back seizures are more serious, and clusters lasting over 15 minutes are a medical emergency. [7]
What causes atonic seizures?
An abnormal surge of electrical activity in the brain areas that regulate muscle tone, especially the frontal lobe and brainstem. The reason the surge occurs is unknown. [7]
Who gets atonic seizures?
Being younger than 18 raises the risk. Risk is higher with a history of infantile spasms or underlying conditions like Lennox-Gastaut syndrome and Dravet syndrome. [7] Some seizures continue into adulthood, though adult diagnosis is less common. [1]
What medications treat atonic seizures?
Common options include benzodiazepines (clonazepam, clobazam), felbamate, levetiracetam, topiramate, valproic acid, and zonisamide. If medications fail or injuries keep occurring, other options include surgery, vagus nerve stimulation, and protective headgear. [1]
What is the difference between atonic and tonic seizures?
In atonic seizures, muscles weaken and the person slumps or collapses. In tonic seizures, muscles tighten and stiffen, causing a rigid fall "like a tree being chopped down." [7] Convulsions are uncommon with atonic seizures, but consciousness may still be lost.
What is the ketogenic diet's role in treatment?
In some cases, a doctor may recommend the ketogenic diet, a specialized, high-fat medical diet, which can help manage seizures, particularly in children. [1]
When should I go to the ER?
Seek emergency care for a first-time seizure, a severe injury during a seizure (such as a broken bone), or multiple back-to-back seizures: more than three within 30 minutes. [7]
Related Reading
References
Kiriakopoulos E; reviewed by Fisher R. Atonic Seizures. Epilepsy Foundation. Accessed October 15, 2026. https://www.epilepsy.com/what-is-epilepsy/seizure-types/atonic-seizures
National Institute of Neurological Disorders and Stroke. Epilepsy and Seizures. NINDS Health Information. Last reviewed March 13, 2026. Accessed October 15, 2026. https://www.ninds.nih.gov/health-information/disorders/epilepsy-and-seizures
Victorio MC. Seizures in Children. Merck Manual Consumer Version. Last updated July 2026. Accessed October 15, 2026. https://www.merckmanuals.com/home/children-s-health-issues/neurologic-disorders-in-children/seizures-in-children
Alhiniah M, Alshahrani A, Rajab R, et al. Treatment of drop attacks: anti-seizure drug choices of pediatric neurologists in Saudi Arabia. Neurosciences (Riyadh). 2023;28(3):170-176. PMID: 37482388. https://doi.org/10.17712/nsj.2023.3.20230008
Hancock EC, Cross JH. Treatment of Lennox-Gastaut syndrome. Cochrane Database Syst Rev. 2013;(2):CD003277. PMID: 23450537. https://doi.org/10.1002/14651858.CD003277.pub3
Devinsky O, Patel AD, Cross JH, et al. Effect of cannabidiol on drop seizures in the Lennox-Gastaut syndrome. N Engl J Med. 2018;378(20):1888-1897. PMID: 29768152. https://doi.org/10.1056/NEJMoa1714631
Cleveland Clinic. Atonic Seizure: What It Is, Causes, Symptoms & Treatment. Cleveland Clinic Health Library. Last updated July 26, 2024. https://my.clevelandclinic.org/health/diseases/atonic-seizure
Medical disclaimer
The information provided in this article is for educational purposes only and is not intended as medical advice. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. If you or someone else experiences a first-time seizure, a severe injury, or seizures lasting more than 15 minutes, seek emergency medical care immediately.
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