clonus vs tic

clonus

noun
  • A muscular spasm with regular contractions. 

tic

noun
  • A sudden, nonrhythmic motor movement or vocalization. 

  • ticket 

  • Something that is done or produced habitually or characteristically. 

verb
  • To exhibit a tic; to undergo a sudden, semi-voluntary muscle movement. 

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