Juvenile myoclonic epilepsy, also known as impulsive petit mal seizures or Janz syndrome, is an inherited epilepsy syndrome. Typically presenting in adolescence, JME is usually a life-long condition. According to the University of Maryland Medical Center, JME accounts for approximately 7 percent of all epilepsy cases. JME is usually well controlled with antiseizure medication; valproate is commonly used. Characteristic symptoms of JME distinguish this condition from the many other forms of epilepsy.
Myoclonic Jerks
Quick, involuntary, jerking movements of the arms, neck or shoulders, called "myoclonic activity," characterize JME. The legs are also sometimes affected, causing falls. Myoclonic activity is much like the common experience of having your legs suddenly jerk as you are falling asleep. With JME, repetitive jerking of this nature occurs and usually involves both sides of the body. There is no loss of consciousness associated with the myoclonic jerking of JME. The Epilepsy Foundation points out that insufficient sleep, stress, use of alcohol or drugs, intense emotions, menstruation, and flashing or flickering lights may trigger myoclonic jerking. Notably, myoclonic jerking often occurs in the first few hours after awakening.
Generalized Seizures
In a 2008 article published in Epilepsy Currents, Dr. Bassel Abou-Khalil reported that approximately 90 percent of people with JME experience generalized tonic-clonic seizures. A generalized tonic-clonic seizure involves sudden loss of consciousness and stiffening of the body followed by jerking movements throughout the body. Generalized tonic-clonic seizures are also known as grand mal seizures. In people with JME, a generalized tonic-clonic seizure often follows the characteristic myoclonic jerks associated with the disorder.
Absence Seizures
"The Merck Manual for Healthcare Professionals" reports approximately one-third of people with JME also have absence or petit mal seizures. An absence seizure is a brief loss of conscious awareness of self and surroundings. Typically lasting less than 30 seconds, the affected person suddenly stops activity but does not fall. He appears to be staring blankly into space. When the seizure ends, he generally resumes whatever he had been doing without awareness of the absence seizure. With JME, absence seizures most frequently occur in the hours immediately after awakening.
References
- Epilepsy Foundation: Juvenile Myoclonic Epilepsy
- Epilepsy.com/Professionals: Juvenile Myoclonic Epilepsy
- University of Maryland Medical Center: Epilepsy
- Merck Manual for Healthcare Professionals: Seizure Disorders, Generalized Seizures
- Epilepsy Currents: Juvenile Myoclonic Epilepsy--More Trials Are Needed to Guide Therapy
