deviate vs lose the thread

deviate

verb
  • To go off course from; to change course; to change plans. 

  • To cause to diverge. 

  • To fall outside of, or part from, some norm; to stray. 

noun
  • A person with deviant behaviour; a deviant, degenerate or pervert. 

  • A value equal to the difference between a measured variable factor and a fixed or algorithmic reference value. 

lose the thread

verb
  • To get distracted and lose track of something (one's train of thought, a conversation). 

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