Myoclonus

Excerpt

Myoclonus is defined as rapid, brief, jerky, or shock-like movements involving muscle or group of muscles. Among all hyperkinetic movement disorders, myoclonus is considered to be the most rapid and brief. When caused by sudden muscle contractions, it is known as 'positive myoclonus', while a brief loss of muscular tone results in 'negative myoclonus' such as in asterixis.

Myoclonus is classified in different ways according to its physiology, anatomical site of origin, and etiology. As with most movement disorders, myoclonus can be focal, multifocal, segmental, or generalized.

Myoclonus is one of the signs in a wide variety of nervous system disorders such as dystonia, multiple sclerosis, Parkinson's disease, Creutzfeldt-Jakob disease (CJD), serotonin toxicity, Huntington disease, subacute sclerosing panencephalitis, Alzheimer's disease, and Gaucher disease.