Myoclonic Seizure

What is a myoclonic seizure?

A myoclonic seizure causes one or more muscles to quickly and uncontrollably jerk. These movements last just a few seconds, and you may remain fully conscious and aware while they happen. You may have one myoclonic seizure or several over a short time.

Myoclonic seizures are more common in children and adults who have certain types of (a seizure disorder). They happen due to abnormal brain activity. People with recurrent myoclonic seizures typically need treatment.

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 myoclonic seizures in children.

What are the symptoms of a myoclonic seizure?

Symptoms of myoclonic seizures can be easy to miss. Myoclonic seizures:

• Are brief: The jerky movement of a myoclonic seizure starts and ends quickly. Muscles tighten or jerk for one or more seconds.
• May occur while you’re conscious: Unlike many other, when the myoclonic seizure ends, you may be able to resume activities quickly.
• Affect a small area: Jerking movements often occur in a single muscle or a small group of muscles in your arms, legs, or face. Less commonly, they can affect muscles in your chest, back, or abdomen.
• Happen in limited numbers: Some people have a single myoclonic seizure, while others may experience several myoclonic seizures in a short period.

Causes of myoclonic seizures

Epilepsy is often the cause of myoclonic seizures. occurs when there’s abnormal electrical activity in the brain. Nerve cells in the brain (neurons) send too many electrical signals to your muscles, causing the myoclonic seizure.

These types of epilepsy are more likely to cause myoclonic seizures:

• Juvenile myoclonic epilepsy (JME): JME typically begins around puberty. It causes myoclonic seizures in the upper arms, shoulders, and neck.
• Lennox-Gastaut syndrome: This rare type of epilepsy can cause multiple types of seizures, including myoclonic seizures. It may also involve:
  • Atonic seizures, where muscles suddenly go limp
  • Tonic seizures, where muscles become stiff
• Progressive myoclonic epilepsies (PME): This group of rare epilepsies cause both myoclonic seizures and tonic-clonic (convulsive or grand mal) seizures.

Triggers of myoclonic seizures

Many people have myoclonic seizures in the morning, especially right after waking up. Certain things may trigger a myoclonic seizure:

• Drinking alcohol
• Fatigue or lack of sleep
• Flashing lights
• Stress or anxiety

Risk factors for myoclonic seizures

In addition to certain types of epilepsy, myoclonic seizures can occur with any condition that disrupts brain activity and function. You may be more prone to myoclonic seizures if you have:

• Brain infection, such as meningitis or encephalitis
• Brain tumor
• Concussion or traumatic brain injury
• Degenerative brain disease, such as dementia or Alzheimer’s disease
• Lack of oxygen to the brain (cerebral hypoxia)
• Substance use disorder or withdrawal
• Too high or too low blood sugar

Learn more about epilepsy symptoms, diagnosis, and treatments from a Mass General Brigham epilepsy specialist.

Diagnosis of myoclonic seizures

Doctors begin diagnosing myoclonic seizures by reviewing your symptoms and medical history. To confirm the diagnosis, you or your child may get an electroencephalogram (EEG). This test detects changes in the brain’s electrical activity that cause different types of seizures.

Treatment of myoclonic seizures

Treatment focuses on managing epilepsy or other underlying conditions causing the seizures. In many cases, seizure medications may prevent, or control, myoclonic seizures.

Medications for myoclonic seizures include:

• Levetiracetam
• Valpoic Acid
• Clonazepam
• Clobazam
• Diazepam nasal spray
• Diazepam rectal gel
• Midazolam nasal spray

Call the Epilepsy Center at 617-726-3311 to schedule an appointment.

FAQs about myoclonic seizures