myoclonus vs tremor

myoclonus

noun
  • The brief, involuntary twitching of a muscle or group of muscles. 

tremor

noun
  • A rhythmic, uncontrollable shaking of all or part of the body due to partial muscle contractions. 

  • An earthquake. 

  • A shake, quiver, or vibration. 

verb
  • To shake or quiver excessively and rapidly or involuntarily; to tremble. 

How often have the words myoclonus and tremor occurred in a corpus of books? (source: Google Ngram Viewer )