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Myoclonic seizures

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What is a myoclonic seizure?

Myoclonic seizures can be both generalised (affecting both sides of the brain) and focal seizure types (affecting one side).   

You are usually awake during a myoclonic seizure – this can often happen just after waking or when you are tired before going to bed.

It’s the one where your body suddenly jerks—like a jolt—and whatever you’re holding might go flying. 

- Description from young people with epilepsy in the Youth Voice Network.

The name of this seizure describes what happens during this type of seizure:  

  • ‘Myo’ means ‘muscle’ – the muscles tighten rapidly.   
  • ‘Clonic’ means ‘jerk’ – a burst of abnormal electrical activity in the part of the brain that controls the muscles causes sudden jerking in the head, arms, legs, neck or body. 

Myoclonic seizures happen in a variety of epilepsy syndromes, such as juvenile myoclonic epilepsy syndrome. 

What do myoclonic seizures look like?

Myoclonic seizures cause sudden, brief jerks or twitches in the muscles—often in the arms, legs, or upper body. These movements can be strong enough to make someone drop what they’re holding or jolt in a way that looks unexpected or out of place. 

During this type of seizure, you might also roll your eyes, blink, nod, make coughing sounds, or fall to the ground (if you’re standing).   

What do myoclonic seizures feel like?

The seizure only lasts a second or two, and the person is usually fully aware while it’s happening. That can make it feel unsettling or even embarrassing, especially in public or around friends. While it might not look like much from the outside, it can be a scary and confusing experience for the person going through it. 

Understanding that it’s a seizure—not clumsiness or a reaction—can help others respond with empathy and support. 

If you are there when someone has a myoclonic seizure, listen to how they want to be supported.

How to help someone having a myoclonic seizure

You told us what really helps when you're having a seizure, and we listened. This guidance is shaped by a powerful mix of lived experience and clinically informed expert advice, coming together to help others know what to do.

Even though they only last a few seconds, a myoclonic seizure can be scary and confusing for both the person experiencing it and the person witnessing it. But you can help.  

To help someone who is having a myoclonic seizure, follow these steps: 

  • Stay with them and make sure they’re safe. 
    • Move any hazards, like furniture, out of the way.
    • Don’t move them unless it’s absolutely necessary, for example, if they are close to a hazard that cannot be moved, like an open fire, roads or open water. 
  • Be calm and reassure them, even if you think they can't hear you. This isn’t always easy, but it’s very important, especially when the person is recovering from the seizure and looking to you for reassurance.
  • Make sure they’re okay and haven’t hurt themself. 
    • Don’t try and restrain them.
    • Don’t let strangers film them on their phones.
    • Please don't put anything in their mouth.
  • Listen to how they want to be supported.
    • How they feel after the seizure can be different each time. 
    • They might feel tired, confused and upset. Or they might feel okay. 

Call an ambulance if they’ve seriously injured themself, or if they have lots of seizures in a short space of time. 

The person may have an emergency management or care plan. If they do, you should follow the instructions in their plan. Their plan may include giving them their prescribed emergency medication, but do not administer emergency medication unless you are trained to do so. If you have to call 999, stay on the line and follow the guidance of the call handler. Find out more about emergency medication.

Treating myoclonic seizures

If you have myoclonic seizures, your doctor may suggest you start by trying a single med. For example, levetiracetam or sodium valproate. If this treatment does not work or you have side effects, your doctor may suggest you try a different med either on its own or as an add-on. 

If both of these meds do not work, your doctor may suggest different mediations.  

If you’d like to know more about what meds you might be offered, talk to your doctor. Or go to the NICE website to read the most up-to-date guidelines.

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Find out how the new seizure films were made with young people at the heart - what they want you to understand about their seizure type and how you can help.

Last reviewed July 2025.

Next review due July 2028.

If you would like to find out more about how we produce our information, or the sources of evidence we use, please contact us at healthinfo@youngepilepsy.org.uk