Juvenile Myoclonic Epilepsy

What is juvenile myoclonic epilepsy?

Juvenile myoclonic epilepsy (JME), also known as Janz syndrome, is a type of epilepsy that typically begins in the teenage years. It causes quick, involuntary muscle jerks (called myoclonic seizures), often in the arms or shoulders. These jerks usually happen shortly after waking up in the morning or after a nap. This can also be associated with other seizure types. JME can also cause short periods of “spacing out” that typically last only a few seconds.

Medication controls seizures in most people with juvenile myoclonic epilepsy. With proper treatment, people with JME can lead full, active lives.

As a Level 4 Epilepsy Center, certified by the National Association of Epilepsy Centers, Massachusetts General Hospital provides the highest level of epilepsy care available. Our team provides advanced neurodiagnostic monitoring, along with comprehensive medical, neuropsychological, and psychosocial treatment for even the most complex cases. We also offer full evaluations for epilepsy surgery, including intracranial monitoring and specialized surgical procedures that are not widely available at other institutions.

The Pediatric Epilepsy Program at Mass General Brigham for Children provides advanced diagnostic tests and treatments for epilepsy conditions that cause seizures in children.

Conditions that may look like juvenile myoclonic epilepsy

Other types of epilepsy have symptoms and patterns that are similar to juvenile myoclonic epilepsy. Conditions that can resemble JME include:

• Eyelid myoclonia with absences: A type of epilepsy that causes eyelid jerks (eyelid myoclonia) and loss of awareness (absence seizure)
• Non-epileptic seizures: Seizures that resemble epilepsy but do not result from the type of brain changes that cause epilepsy
• Photosensitive occipital epilepsy: A type of epilepsy only triggered by flashing lights
• Progressive myoclonic epilepsy: A more severe type of myoclonic epilepsy that worsens over time and typically does not respond to medication

Juvenile myoclonic epilepsy symptoms

Juvenile myoclonic seizures involve quick jerks in the arms, neck, and shoulders after waking up. People with this condition often say the jerks feel like shocks.

People with juvenile myoclonic epilepsy also may experience two other types of seizures:

• Generalized tonic-clonic seizures: This type of seizure, formerly called "grand mal seizure," begins when all of the muscles stiffen (tonic phase). Then, the arms and legs begin to jerk rapidly and rhythmically (clonic phase). Generalized tonic-clonic seizures usually happen after myoclonic seizures in people with JME. Most people with JME experience tonic-clonic seizures.
• Absence seizures: These seizures are short periods of “blanking out” or “spacing out” that typically last only a few seconds. Not everyone with JME experiences absence seizures.

What to do if someone is having a seizure

Seeing someone have a seizure can be scary, but by following the right steps and staying calm, you can make sure everyone stays safe. Ali S. Raja, MD, executive vice chair, Department of Emergency Medicine at Massachusetts General Hospital, explains how to keep someone comfortable and safe during and after a seizure.

Causes of juvenile myoclonic epilepsy

Juvenile myoclonic epilepsy is a genetic (inherited) disease. Around half of people with JME have a family member who also has the condition. Having a family history of epilepsy is the main risk factor for JME.

Seizure triggers can vary among people with juvenile myoclonic epilepsy. Common triggers of JME seizures include:

• Alcohol, especially excessive drinking
• Bright, flashing, or flickering lights
• Caffeine
• Fatigue or sleep deprivation
• Stress

Diagnosis of juvenile myoclonic epilepsy

Diagnosing juvenile myoclonic epilepsy involves a careful review of your symptoms, medical history, and brain activity. Your neurologist may take the following steps:

• Review your family history of epilepsy or neurological conditions
• Ask about your seizure history, including when symptoms started and what happens during a seizure
• Review your health history
• Perform physical and neurological exams
• Order an EEG (electroencephalogram) to look for specific patterns of abnormal brain activity associated with JME

Juvenile myoclonic epilepsy treatment

Juvenile myoclonic epilepsy treatment typically involves daily medication tailored to the types of seizures you have. With proper treatment, most people with JME achieve good seizure control and lead full, active lives.

Anti-seizure medications for juvenile myoclonic epilepsy include:

• Valproic acid
• Lamotrigine
• Levetiracetam

Add-on or emergency medications to help control seizures include:

• Clonazepam
• Topiramate
• Zonisamide

In addition to medication, lifestyle choices play an important role in managing juvenile myoclonic epilepsy. To reduce seizure risk, it’s important to:

• Get consistent, quality sleep
• Avoid sleep deprivation
• Limit or avoid alcohol
• Manage stress through relaxation techniques or counseling

Surgery for juvenile myoclonic epilepsy

Most people with JME respond well to medication. If medication does not control seizures, there are several surgical options available. Implantable neurostimulation devices, which disrupt electrical signals that cause seizures, can reduce seizures. These devices include vagus nerve stimulation (VNS) and responsive neurostimulation (RNS). Our epilepsy experts perform a comprehensive evaluation to understand your unique condition and whether epilepsy surgery may be the right treatment for you.

FAQs about juvenile myoclonic epilepsy