Involuntary shock-like contractions, irregular in rhythm and amplitude, followed by relaxation, of a muscle or a group of muscles. This condition may be a feature of some CENTRAL NERVOUS SYSTEM DISEASES; (e.g., EPILEPSY, MYOCLONIC). Nocturnal myoclonus is the principal feature of the NOCTURNAL MYOCLONUS SYNDROME. (From Adams et al., Principles of Neurology, 6th ed, pp102-3).
shock-like contraction of a portion of a muscle, an entire muscle, or a group of muscles; may be part of a disease process or a normal physiological response.
A sudden, brief, strong contraction of a muscle or group of muscles that cannot be controlled.
A sudden, involuntary contraction of a muscle or group of muscles; these movements may develop as a symptom of a number of neurological diseases including epilepsy, Parkinson`s disease, Alzheimer`s disease, or Creutzfeldt-Jacob disease.