Myoclonus

Description

Myoclonus comes from the Greek words for muscle (myo) and tumult (clonus) and refers to sudden, brief, shock-like movements, which can be positive or negative. Positive myoclonus results in contraction of a muscle or multiple muscles. Asterixis, or negative myoclonus, occurs with brief momentary loss of agonist muscle tone and subsequent contraction of antagonist muscles, resulting in a flapping motion. These nonsuppressible movements often have a characteristic saw-tooth pattern and usually disappear during sleep.

William A. Hammond, an early American neurologist, published a paper in 1873 on convulsive tremor in the American Journal of Sanity in which he described a patient with what later came to be known as myoclonus. Nikolaus Friedreich is credited with publishing the first description of the disorder (1881) and using the term paramyoklonus mulitplex (literally—symmetric quick movements of the muscle in multiple sites) to describe the multifocal jerks of his 50-year-old patient.

Please see the following topics related to myoclonus below, and available on the left side of this page.

• Classification of Myoclonus
• Clinical Classification
• Etiologic Classification
• Pathophysiology
• Epidemiology
• Diagnosis
• Treatment
• Additional Resources
• References

For pediatric myoclonus, see: Pediatric Movement Disorders - Myoclonus.

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Myoclonus Slide Set	Myoclonus Rating Scales	Anatomical Illustrations