The inter-aural attenuation for bone conduction (BC) is?

Bone conduction testing is an important aspect of audiometry used to evaluate the ability of the inner ear's structures to transmit sound. When discussing inter-aural attenuation (IA), it refers to the difference in sound level that the ear not receiving the stimulus is subjected to due to the physical barriers of the head.

For bone conduction, the inter-aural attenuation is considered to be 0 dB. This is because bone conduction bypasses the outer and middle ear and directly stimulates the inner ear through the skull. As a result, there is no reduction in sound intensity when the signal reaches the opposite ear. Therefore, if a bone conduction sound is heard in one ear, it can be assumed that it could also be heard in the opposite ear at the same intensity without any attenuation.

This understanding is crucial as it informs clinicians about how to interpret bone conduction results in the context of the entire audiometric evaluation. In contrast, air conduction usually has a higher inter-aural attenuation, typically around 40 dB, which prevents cross-hearing in many testing scenarios.