attention deficit hyperactivity disorder vs tic

attention deficit hyperactivity disorder

noun
  • A developmental disorder in which a person has a persistent pattern of impulsiveness and inattention, with or without a component of hyperactivity. 

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 attention deficit hyperactivity disorder and tic occurred in a corpus of books? (source: Google Ngram Viewer )