audiologist vs logopedist

audiologist

noun
  • A healthcare professional who diagnoses, treats and/or manages hearing and balance disorders. 

logopedist

noun
  • A specialist who deals with the correction of the speech sounds, the disorders in writing, reading, the ability to create any forms of mathematical operations, disorders in use of language and swallowing disorders. 

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