Solving audiometric masking dilemmas with an insert masker.

For some bilateral hearing losses, standard audiometric techniques cannot provide sufficient data for correct otologic diagnosis. These hearing losses are termed "masking dilemmas" because sound attenuation across the head is inadequate to prevent unwanted masking of the test cochlea. In most cases, the masking dilemma can be eliminated by presenting masking through an insert phone in the ear canal, rather than through a standard earphone and cushion. Insert earphones are not standard on most audiometers, but the minimal necessary equipment and alterations are inexpensive, readily available, and require little time to implement. Test time is not increased significantly. Some masking dilemmas will not be solved by the insert masker, but, when properly constructed and used, an insert masker will provide an accurate measurement of cochlear reserve not otherwise obtainable for most cases.