When measuring bone conduction thresholds without masking, what is the assumption about the better ear?

The assumption in this context is that unmasked bone conduction thresholds may not accurately represent the true hearing levels in cases where there is a significant air-bone gap or unilateral hearing loss. When bone conduction testing is conducted without masking, the sound can stimulate both ears, leading to the possibility that responses are coming from the better ear, but this isn't guaranteed.

The correct interpretation is that only by using masking techniques can a clinician ensure that the test results specifically reflect the capabilities of the ear being tested without influence from the other ear. Therefore, masking is essential to isolate the ear with better hearing ability and obtain precise measurements. This ensures that the results are not artificially influenced by the presence of better hearing in the opposite ear.