BC thresholds cannot be worse than which type of thresholds?

The correct answer is that bone conduction (BC) thresholds cannot be worse than air conduction (AC) thresholds. This relationship is critical in understanding hearing loss types and how they are measured.

BC thresholds represent the sensitivity of the cochlea and the auditory pathways to sound when bypassing the outer and middle ear. This measurement reflects the function of the inner ear and neural pathways, as it assesses the processing of sound that occurs directly within the auditory system.

In contrast, AC thresholds include the entire auditory pathway—outer, middle, and inner ear. If there is an issue in the outer or middle ear, such as hearing loss caused by earwax buildup or a perforated eardrum, the AC thresholds will be poorer compared to the BC thresholds because these conditions hinder sound from reaching the inner ear effectively.

For this reason, AC thresholds can be equal to or worse than BC thresholds, but BC thresholds will never be worse than AC thresholds. Understanding this relationship aids audiologists and hearing aid dispensers in diagnosing types of hearing loss—whether conductive, sensorineural, or mixed.