Encyclopedia of Clinical Neuropsychology

2018 Edition
| Editors: Jeffrey S. Kreutzer, John DeLuca, Bruce Caplan


  • Anna DePold HohlerEmail author
  • Marcus Ponce de Leon
Reference work entry
DOI: https://doi.org/10.1007/978-3-319-57111-9_470


Jerk; Twitch


Myoclonus is a brief, shock-like, involuntary jerk of a muscle or a group of muscles. Contractions are called positive myoclonus; relaxations are called negative myoclonus. Myoclonic jerks may occur alone or in sequence. They may occur infrequently or many times each minute.


Anatomically, myoclonus may originate from lesions of the cortex, subcortex, or spinal cord. Myoclonus may be related to seizures, neoplasm, and neurodegenerative disorders, as a result of toxin exposure, medication side effect, or as a result of renal or hepatic impairment. It may be seen with hypoxic ischemic events, lipid storage diseases, and spinal cord injury. It may be seen at rest or provoked by movement or sound.


Myoclonus is a common movement disorder often seen in hospitalized patients related to toxic and metabolic issues.

Natural History

Myoclonus related to a metabolic or medication issue may resolve completely when the underlying issue is...

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References and Readings

  1. Obeso, J. A., & Zamarbide, I. (2004). Classification, clinical features, and treatment of myoclonus. In R. L. Watts & W. C. Koller (Eds.), Movement disorders (2nd ed., pp. 659–670). New York: McGraw-Hill.Google Scholar

Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Boston University Medical CenterBostonUSA
  2. 2.Madigan Army Medical CenterTacomaUSA