1. Pure tone audiometry, speech audiometry

From greek.doctor
  • Subjective audiometry
    • Involve attention, reaction time, cooperation, etc
  • Pure tone audiometry
    • The patient is played various frequencies through a headphone (air conduction) and a bone oscillator on mastoid bones
    • Various frequencies are played -> patient gives signal when hearing the sound
    • Auditory threshold is determined for each frequency for each modality
  • Speech audiometry
    • Increasingly loud words are played, which the patient should repeat
      • The percentage of syllables, words or sentences heard is plotted on audiogram
    • Also involves speech recognition


  • Conductive hearing loss
    • Impaired conduction of sound through outer ear, tympanic membrane or middle ear
    • Children and young adults
    • Etiology
      • Tympanic membrane perforation
      • Otitis media with effusion
      • Barotrauma
      • Otosclerosis
    • Diagnosis
      • Pure tone audiometry
        • Auditory threshold increased for air conduction
        • Auditory threshold normal for bone conduction
      • Speech audiometry
        • Increasing loudness eventually leads to 100% speech comprehension
      • Rinne test
        • Unable to hear tuning fork after moving it from mastoid to outer ear
  • Sensorineural hearing loss
    • Lesion of cochlea, vestibulocochlear nerve or central auditory pathways
    • Adults and elderly
    • Etiology
      • Congenital
      • Acquired
        • Presbycusis (aging) (most common cause)
          • Especially high frequencies
        • Ototoxicity
        • Meniere disease
        • Acoustic neuroma
        • Noise-induced hearing loss
        • Trauma
        • Otitis interna
        • Diabetic otopathy
    • Diagnosis
      • Pure tone audiometry
        • Auditory threshold increased for both air and bone conduction
      • Speech audiometry
        • Increasing loudness never leads to 100% speech comprehension
  • Combined hearing loss
    • Diagnosis
      • Pure tone
        • Auditory threshold is increased for both air and bone conduction, but it is increased more for air conduction
  • Tuning fork tests
    • Distinguish conductive and SNHL
    • Weber test
      • Tests for lateralization (sound is louder in one ear)
      • Base of tuning fork on the middle of forehead – bone conduction to cochlea
      • Interpretation
        • Lateralization to one ear = contralateral sensorineural HL or ipsilateral conductive HL
        • No lateralization = normal hearing or bilateral HL
    • Rinne test
      • Tests for air conduction and bone conduction
      • Base of tuning fork on the mastoid process
        • -> which side is louder?
        • -> when the patient no longer hears the tone, move front of the fork to the outer ear and ask if the patient still hears it
          • Air conduction is greater than bone, so patient should still hear the fork
      • Interpretation
        • Sound is louder with air than bone conduction (positive Rinne) = no conductive HL in examined ear
        • Sound is louder with bone than with air conduction (negative Rinne) = conductive HL in examined ear
  • Noise-induced hearing loss
    • Excessive noise causes direct mechanical and metabolic injury
    • Types
      • Acute acoustic trauma
        • < 1,5 ms sound of >140 dB
        • Gunshot, airbags, fireworks
      • Blast injury
        • Pressure wave ruptures tympanic membrane
      • Acute noise-induced hearing loss
        • Seconds – hours
        • Jet engine, concerts, power tools
        • Often reversible
      • Chronic noise-induced hearing loss
        • Chronic exposure to loud sounds
        • Loud music, party
    • Clinical features
      • Muffled sensation
      • Tinnitus
    • Diagnosis
      • Hearing threshold decreased at all frequencies, especially 3 – 6 kHz