Myoclonic seizures are a specific type of seizure that cause sudden short jerk-like twitches in the muscles of the arms and legs. “Myo” means muscle and “clonus” means quickly switching to and from tensing and relaxing; so the word myoclonus means the quick tensing and relaxing of muscles. This type of seizure is very short, typically lasting only a second or two. In fact, many people who do not have seizures can have myoclonus that causes their body to suddenly jerk themselves awake after falling asleep. Myoclonic seizures often occur as a part of other epilepsy conditions, such as juvenile myoclonic epilepsy, Lennox-Gastaut syndrome, and progressive myoclonic epilepsy. When myoclonic seizures occur as part of an epilepsy condition, they tend to cause abnormal movements on both sides of the body at the same time. After a myoclonic seizure, a person is usually awake and can continue on with their normal activity. Epilepsy conditions that include myoclonic seizures usually begin in childhood but the seizures can occur at any age.
There are many causes of epilepsy conditions that include myoclonic seizures. These include genetic causes, head trauma, brain abnormalities, infectious diseases and injuries that occur before a baby is born (prenatal injury). Risk factors for epilepsy conditions include age (epilepsy conditions usually present in childhood or after the age of 60 years), previous head trauma and a family history of epilepsy conditions. To diagnose myoclonic seizures, doctors will typically take a detailed medical history and perform a test called electroencephalogram (EEG). EEGs test the brain for abnormal electrical activity associated with a seizure. Many people with myoclonic seizures can be treated with anti-epilepsy medications. Talk with your doctor to decide which treatment option is best for you or your child. Support groups are a good resource for support and additional information.