confounding vs disarticulation

confounding

noun
  • The act by which things are confounded, or confused. 

  • The process by which an apparent association between an exposure and an outcome is actually explained by another factor. 

disarticulation

noun
  • The act of disarticulating. 

  • Some amputations: where a joint is disarticulated: e.g. knee, hip, elbow or shoulder disarticulation. 

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