Myoclonus is the sudden involuntary contraction or relaxation of a muscle or group of muscles. Myoclonus is not a disease but a sign of several diseases or conditions that affect the brain or spinal cord. It can be mild, affecting only a single muscle, or more severe, affecting groups of muscles throughout the body.
Myoclonus can be caused by:
Myoclonus is typically treated with barbiturates, which slow down the action of the central nervous system.