Different Types of Myoclonic Seizures

Myoclonus is "a sudden, involuntary twitching of a muscle or group of muscles" (National Institute of Neurological Disorders and Stroke). The twitching or jerking can occur for a variety of reasons, the effects of which range from mild to severe and have many triggers and stimuli. This article will focus only on the types of myoclonic seizures.

Action Myoclonus

• This is caused or exacerbated by voluntary movement or the intent to move, and can be extremely disabling. It is often caused by deprivation of oxygen and blood flow to the brain by a stopped heartbeat or stopped breathing (even temporarily).

Cortical Reflex Myoclonus

• This seizure is thought to start in the cerebral cortex that processes information. It may affect a few muscles or many muscles. It may occur during one particular action or when perceiving a certain sensation.

Essential Myoclonus

• This form can occur at random in families with no history of epilepsy or in families where other members are affected. It tends not to progress but to remain stable, and appears to have no known cause.

Palatal Myoclonus

• This seizure presents as a rhythmic muscular contraction in the soft palate at the rear of the mouth, that may be perceived as a "clicking" sound in the person's ear many times per minute. It is usually mild and can last a long time.

Progressive Myoclonus Epilepsy (PME)

• These are a group of serious diseases that start in childhood and adolescence, are progressive and can be fatal. Multiple disorders and complications are involved with these diseases, which are classified into three groups: Lafora body disease, cerebral storage disease and system degenerations.

Reticular Reflex Myoclonus

• This seizure affects the whole body and starts in the brain stem, which involves vital functions like breathing and the heartbeat. The whole body jerks and shakes, either from voluntary movement or external stimulus.