What causes air-bone gap?

An air-bone gap occurs when there is a difference in hearing sensitivity between air conduction and bone conduction pathways. It is typically caused by conductive hearing loss, which can result from factors like fluid in the middle ear, earwax blockage, eardrum perforation, or ossicular chain dysfunction. These issues prevent sound from efficiently traveling through the air to the inner ear, while bone conduction bypasses these obstacles, leading to the observed gap in hearing thresholds.