What does a bone conduction test primarily determine?

A bone conduction test is primarily designed to evaluate the threshold of the cochlea directly. This test involves placing a bone conduction vibrator against the skull, usually behind the ear, which sends vibrations directly to the inner ear (cochlea) bypassing the outer and middle ear. By doing this, clinicians can assess the sensory-neural function of the hearing mechanism; specifically, it helps determine how well sound signals are being processed by the cochlea.

When interpreting the results, the thresholds obtained from bone conduction testing indicate whether the cochlea is functioning normally or if there is any damage or impairment within it. If the results show normal thresholds for bone conduction but not for air conduction, this typically indicates a conductive hearing loss, suggesting problems in the outer or middle ear rather than the cochlea itself.