dotage vs softening of the brain

dotage

noun
  • Fondness or attentiveness, especially to an excessive degree. 

  • Decline in judgment and other cognitive functions, associated with aging; senility. 

  • Foolish utterance(s); drivel. 

softening of the brain

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