This site is intended for healthcare professionals

Go to /sign-in page

You can view 5 more pages before signing in

JME (juvenile myoclonic epilepsy)

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

Myoclonic seizures are brief, shock-like jerks of a muscle or a group of muscles

  • "Myo" means muscle and "clonus" (KLOH-nus) means rapidly alternating contraction and relaxation - jerking or twitching - of a muscle
    • myoclonic seizures
      • sudden brief (< 100 ms) and almost shock-like involuntary single or multiple jerks due to abnormal excessive or synchronous neuronal activity and associated with polyspikes on EEG (1)
    • usually last no more than a few seconds
    • may occur singularly but sometimes many will occur within a short time
    • note that people without epilepsy can experience myoclonus in hiccups or in a sudden jerk that may wake you up as you're just falling asleep - these are normal (2)

In epilepsy, myoclonic seizures usually cause abnormal movements on both sides of the body at the same time. They occur in a variety of epilepsy syndromes that have different characteristics:

Juvenile myoclonic epilepsy:

  • has an age of onset of 6-22 (peak 10-16 years)
  • accounts for 4-12 % of childhood epilepsy
  • seizures usually involve the neck, shoulders, and upper arms
  • generally the seizure occurs in the first hour after waking
  • epileptogeneic photosensitivity occurs in at least half of patients with JME
  • in most cases, these seizures can be well controlled with medication but it must be continued throughout life

Lennox-Gastaut syndrome:

  • is an uncommon syndrome that usually includes other types of seizures as well
  • begins in early childhood
  • myoclonic seizures usually involve the neck, shoulders, upper arms, and often the face. They may be quite strong and are difficult to control.

Progressive myoclonic epilepsy:

  • the rare syndromes in this category feature a combination of myoclonic seizures and tonic-clonic seizures
  • treatment is usually not successful for very long, as the patient deteriorates over time


  • if the person has myoclonic seizures or is suspected of having juvenile myoclonic epilepsy (JME), be aware that lamotrigine may exacerbate myoclonic seizures (1)
  • carbamazepine and oxcarbazepine have the risk of exacerbating myoclonic or absence seizures (1)


Related pages

Create an account to add page annotations

Add information to this page that would be handy to have on hand during a consultation, such as a web address or phone number. This information will always be displayed when you visit this page

The content herein is provided for informational purposes and does not replace the need to apply professional clinical judgement when diagnosing or treating any medical condition. A licensed medical practitioner should be consulted for diagnosis and treatment of any and all medical conditions.


Copyright 2024 Oxbridge Solutions Limited, a subsidiary of OmniaMed Communications Limited. All rights reserved. Any distribution or duplication of the information contained herein is strictly prohibited. Oxbridge Solutions receives funding from advertising but maintains editorial independence.