Atonic seizures — also known as drop seizures or drop attacks — occur when abnormal electrical activity in the brain causes a person to lose consciousness and muscle tone. As a result, the head can briefly drop, or the body can become limp, and a person may fall or drop what they're holding, leading to accidents and injuries.
UPMC epilepsy experts provide advanced care for atonic seizures, including first-line treatment with anti-seizure medication. If seizures continue despite medications, our neurologists will work with our neurosurgery experts to discuss surgical options to reduce seizure frequency and severity.
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What Are Atonic Seizures?
Atonic seizures — also known as drop seizures or drop attacks — occur when abnormal electrical activity in the brain causes a person to lose consciousness and muscle tone. As a result, the head can briefly drop, or the body can become limp, and a person may fall or drop what they’re holding, leading to accidents and injuries.
How common are atonic seizures?
Atonic seizures are rare in adults but more common in children. They occur in about 1% to 3% percent of children with epilepsy, and are more common in certain types of epilepsy syndromes.
What causes atonic seizures?
Epileptic seizures are caused by abnormal electrical activity in the brain. Atonic seizures occur when abnormal electrical activity affects the part of the brain that controls muscle tone, such as the frontal lobe or the brainstem.
Atonic seizure risk factors
You may be at higher risk for an atonic seizure if you:
- Are younger than 18 years of age.
- Have a history of seizures during infancy.
- Have a childhood seizure disorder such as Lennox-Gastaut syndrome or Dravet syndrome.
Complications of atonic seizures
Atonic seizures can lead to injuries, such as cuts, bruises, broken bones, and brain damage. Having an atonic seizure while driving or operating heavy machinery could be life-threatening to both the person experiencing the seizure and those around them.
Other serious complications of atonic seizures may include:
- Status epilepticus — Long-lasting seizures or seizures that occur one after another.
- Sudden unexplained death in epilepsy (SUDEP) — A rare condition that causes sudden death without a clear cause in people with epilepsy, often during sleep.
How can I prevent atonic seizures?
Seizures can affect anyone, and there’s nothing that can be done to prevent atonic seizures from occurring initially. However, if epileptic seizures have already been diagnosed, you can reduce the risk or frequency of future seizures by avoiding known triggers, taking prescribed medication as directed, getting enough sleep at night, avoiding alcohol and non-prescribed recreational drugs, avoiding dehydration, and letting your provider know if your seizures change or worsen.
What Are the Signs and Symptoms of Atonic Seizures?
Symptoms of atonic seizures may include:
- Temporary loss of consciousness.
- Temporary loss of muscle tone in all or part of your body, such as your head/neck.
These symptoms may cause you to:
- Close your eyes.
- Drop your arms to your side.
- Drop your head to your chest or shoulder.
- Fall.
- Lose your grip on objects you’re holding.
- Slump in your seat.
After the seizure is over, muscle tone will quickly return to normal.
How long do atonic seizures last?
Atonic seizures last about 15 seconds. Most people recover quickly.
Sometimes seizures can occur one after another, which is known as a seizure cluster. If a seizure cluster lasts longer than five minutes, it is a medical emergency.
When should I see a doctor about my atonic seizure symptoms?
If you have an atonic seizure for the first time, you should visit the nearest hospital emergency department and schedule an appointment with your provider as soon as possible.
If you have already been diagnosed with seizures and your symptoms are severe or you experience an injury, dial 911 or ask someone to take you to the nearest hospital emergency department.
How Do You Diagnose Atonic Seizures?
To diagnose atonic seizures, your provider will perform a physical examination and review your symptoms and medical history. Your doctor may also order tests to confirm your diagnosis or rule out other problems.
What to expect during your visit
During your visit, your provider will:
- Ask you about your symptoms.
- Order tests.
- Perform a physical and neurological exam.
- Review your medical history.
Tests to diagnose atonic seizures
Your provider may order tests to confirm your diagnosis or rule out other conditions, including:
- Blood tests — Check for infections and abnormalities.
- Electroencephalogram (EEG) — Checks for abnormal electrical activity in your brain that may cause seizures.
- Magnetic resonance imaging (MRI) — Creates images of your brain and spine using contrast dye to look for damaged or abnormal areas.
- Video-EEG monitoring — Uses EEG in combination with video monitoring to capture physical symptoms during seizures or episodes of concern.
- Neurological examination — A noninvasive test to check your reflexes, balance, movement, memory, and ability to think.
Atonic seizure prognosis
Your prognosis after an atonic seizure diagnosis depends on the severity of your condition. In many cases, atonic seizures can be controlled with antiseizure medications. However, if medications aren’t completely effective, surgical options may be considered.
How Do You Treat Atonic Seizures?
The goals of atonic seizure treatment are to prevent seizures, reduce your risk of injury, minimize treatment-related side effects, and improve quality of life.
Treatment options may include:
Lifestyle changes
If you and your epilepsy care team can identify triggers that lead to atonic seizures, you may be able to make lifestyle changes to reduce the number of seizures you experience.
Dietary changes
Your provider may recommend following a specialized, high-fat, low-carbohydrate diet, such as the ketogenic diet, to help manage seizures in certain circumstances.
Medications for epilepsy
Medications are first-line treatment for atonic seizures and help to control atonic seizures in most people with epilepsy. Your provider will work with you to identify the medications, or combination of medications, that work best for you with minimal side effects.
Surgery to treat epilepsy
In at least one-third of people with epilepsy, seizures persist despite medication.
Epilepsy surgery may be an effective option if:
- Medication side effects are not tolerable.
- At least two different medications have not been effective at controlling seizures.
UPMC neurosurgeons offer a range of surgical options for people with epilepsy, including:
Diagnostic surgery
Also known as intracranial monitoring or stereo-EEG, this procedure helps neurosurgeons pinpoint the origin of seizures within the brain. UPMC neurosurgeons use the ROSA® robotic-assisted surgery system to perform minimally invasive procedures more accurately for epilepsy and movement disorders.
Neurosurgical procedures
Neurosurgical procedures for epilepsy include:
- Craniotomy for resection of seizure focus — Involves surgically removing the abnormal brain tissue causing seizures.
- Laser ablation — Minimally invasive surgery using focused heat to destroy the abnormal brain tissue causing seizures.
Other less commonly performed surgeries include multiple subpial transections (MST), corpus callosotomy, and other procedures that reduce abnormal electrical impulses in the brain.
Neuromodulation device implantation
Your neurosurgeon may recommend a procedure to implant a neuromodulation device that sends electrical impulses to your brain. These impulses regulate or disrupt abnormal electrical signals, thereby reducing seizures.
Procedures include:
- Vagus nerve stimulation (VNS) — Implantation of a device in the chest that delivers electrical impulses to the vagus nerve in your neck to prevent or disrupt seizures.
- Deep brain stimulation (DBS) — Implantation of electrodes in the brain to directly deliver electrical impulses that can reduce seizure activity.
- Responsive neurostimulation (RNS®) — Implantation of a device within the skull and electrodes within the brain that can detect seizure activity and respond with electrical stimulation to disrupt seizures.
Why Choose UPMC for Atonic Seizure Care?
When you choose UPMC for atonic seizure care, you will receive:
- Multidisciplinary care — Our team of neurologists, epileptologists, and neurosurgeons can work together to develop a customized epilepsy treatment plan that helps you manage seizures and minimize treatment side effects for medication-resistant epilepsy.
- Access to advanced clinical trials — Our team participates in national multicenter clinical trials evaluating new epilepsy treatments, allowing you to contribute to research that advances the care of seizure disorders.
- Expert neurosurgery care — People with medication-resistant epilepsy can access leading-edge, minimally invasive neurosurgery treatment options that reduce seizures and restore quality of life.
