Myoclonus

Myoclonus is a term that refers to brief, involuntary twitching or jerking of a muscle or a group of muscles. It describes a symptom, and generally, is not a diagnosis of a disease. The myoclonic twitches or jerks are usually caused by sudden muscle contractions. They also can result from brief lapses of contraction. Myoclonic twitches or jerks may occur:

  • Alone or in sequence.

  • In a pattern or without pattern.

  • Infrequently or many times each minute.

Often times, myoclonus is one of several symptoms in a wide variety of nervous system disorders such as:

  • Multiple sclerosis.

  • Parkinson's disease.

  • Alzheimer's disease.

  • Creutzfeldt-Jakob disease.

Familiar examples of normal myoclonus include:

  • Hiccups and jerks.

  • "Sleep starts" that some people have while drifting off to sleep.

Severe cases can severely limit a person's ability to:

  • Eat.

  • Talk.

  • Walk.

Myoclonic jerks commonly occur in individuals with epilepsy. The most common types of myoclonus include:

  • Action.

  • Cortical reflex.

  • Essential.

  • Palatal.

  • Progressive myoclonus epilepsy.

  • Reticular reflex.

  • Sleep.

  • Stimulus-sensitive.

TREATMENT

Treatment for myoclonus consists of medicines that may help reduce symptoms. These drugs (many of which are also used to treat epilepsy) include:

  • Barbiturates.

  • Clonazepam.

  • Phenytoin.

  • Primidone.

  • Sodium valproate.

The complex origins of myoclonus may require the use of multiple drugs.