What indicates conductive hearing loss on an audiogram?

The correct choice highlights a significant aspect of interpreting audiograms, particularly in identifying conductive hearing loss. Conductive hearing loss is characterized by a dysfunction in the outer or middle ear that impedes sound from being conducted to the inner ear. This condition typically manifests as a noticeable gap between air conduction and bone conduction thresholds on an audiogram.

When there is a significant difference, this indicates that while sound may not efficiently travel via air conduction, bone conduction—bypassing those outer and middle ear structures—remains relatively intact. This difference essentially points to an issue with conducting sound through the air pathway, distinguishing conductive hearing loss from other types of hearing loss, such as sensorineural loss, where both air and bone conduction thresholds decline together.

The other options do not adequately indicate conductive hearing loss. Normal bone conduction thresholds paired with elevated air conduction thresholds suggest a clear problem with sound transmission through the outer or middle ear, which is indicative of conductive loss. Similar thresholds for both air and bone conduction suggest that the hearing loss is likely due to a sensorineural issue rather than a conductive one. Unexpected spikes in air conduction thresholds could signify temporary disruptions or other anomalies, but they do not specifically correlate with the characteristic air-bone gap required to diagnose conductive hearing loss