What does a 15 dB difference between air conduction and bone conduction indicate?

A difference of 15 dB or more between air conduction and bone conduction thresholds on an audiogram is significant and typically indicates the need for masking. In audiometric testing, masking is used to ensure that the response obtained from the test ear is valid and not influenced by the non-test ear.

When air conduction (the sound heard through the ear canal) is significantly poorer than bone conduction (the sound transmitted through the skull to the inner ear), this discrepancy can suggest a conductive component in the hearing loss. However, if the difference is 15 dB or more, masking should be applied during testing to accurately assess the thresholds, ensuring that the sound presented to the test ear does not cross over and affect the thresholds recorded, particularly when there may be a concern about the ear's involvement or to clarify the type of hearing loss.

Thus, recognizing the need for masking due to a 15 dB or greater difference helps audiologists provide a more accurate diagnosis and appropriate recommendations for hearing management.