What is the purpose of bone conduction testing?

• A. Bypass outer and middle ear to test cochlear function
• B. Assess outer ear canal resonance
• C. Test tympanic membrane mobility
• D. Measure auditory nerve conduction

Answer: (A)

Bone conduction testing bypasses the outer and middle ear to test cochlear function by delivering vibrations directly to the inner ear. This method uses a bone oscillator on the skull, so sound reaches the cochlea without needing the ear canal or tympanic membrane to move. It’s especially useful for distinguishing conductive from sensorineural hearing loss: if bone-conduction thresholds are normal while air-conduction thresholds are reduced, the issue is likely in the outer or middle ear; if both are reduced, the problem is sensorineural. It isn’t used to assess outer ear resonance, tympanic membrane mobility, or direct neural conduction of the auditory nerve.