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Objective audiometry

Revision as of 12:03, 23 November 2023 by Nikolas (talk | contribs) (Created page with "* Objective audiometry ** Doesn’t depend on cooperation and subjective responses of patient * Otoacoustic emissions ** Vibrations of hair cells in cochlea are transmitted back through the conducting apparatus ** Test can only be performed if the middle ear function is normal ** A microphone in the ear canal can detect otoacoustic emissions ** Test reflects functional integrity of cochlea ** Indications *** Screening for cochlear function in newborns **** Cochlear lesio...")
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  • Objective audiometry
    • Doesn’t depend on cooperation and subjective responses of patient
  • Otoacoustic emissions
    • Vibrations of hair cells in cochlea are transmitted back through the conducting apparatus
    • Test can only be performed if the middle ear function is normal
    • A microphone in the ear canal can detect otoacoustic emissions
    • Test reflects functional integrity of cochlea
    • Indications
      • Screening for cochlear function in newborns
        • Cochlear lesions are the major cause of hearing loss in this population
    • Two types
      • Spontaneous otoacoustic emissions
        • Spontaneous, without external stimulus
      • Evoked otoacoustic emissions
        • Stimulated externally
        • Transient evoked OAEs
          • Brief stimulus
        • Distortion product OAEs
          • Two continuous stimuli which distort each other
  • Brainstem evoked response audiometry
    • EEG above mastoid detects the activity of the auditory brainstem response in response to short stimuli
      • Five characteristic waves are seen on the averaged EEG
    • Infants must be sleeping or sedated
    • Indications
      • Determine auditory threshold objectively
      • Intraoperative monitoring
      • Differentiate cochlear and retrocochlear hearing loss‎