An air-bone gap on audiometry suggests:

• A. Sensorineural hearing loss only
• B. Conductive hearing loss component
• C. Central processing problem
• D. No hearing loss

Answer: (B)

An air-bone gap on audiometry signals a conductive component to hearing loss. Air conduction tests the full pathway through the outer and middle ear as well as the inner ear, while bone conduction bypasses the outer and middle ear and directly stimulates the inner ear. If bone-conduction thresholds are better than air-conduction thresholds by a noticeable amount, it means sound transmission through the outer or middle ear is impaired, even though the inner ear is functioning. This points to conductive issues such as fluid in the middle ear, a perforated eardrum, or problems with the ossicular chain. In contrast, a purely sensorineural loss would elevate both air and bone thresholds similarly with little or no gap, and no hearing loss would show normal results with no gap.