I agree with Bob Siegel...You should have a repeat audiogram done to determine
your true bone levels. It sounds like the Audiologist who conducted your
assessment was using TDH style headphones (the ones that look like regular
stereo headphones, only larger...) When you use the TDH headphones, then the
chances of running into a masking dilemma is much more likely, as interaural
attenuation (IA) occurs around 45-50 dB HL. In your case, the masking level
needed to block out the nontest ear would be greater than the maximum IA using
the TDH headphones. As a result, the masking noise actually crosses over to the
test ear through the bones of the skull, potentially making your true bone
conduction levels look poorer than they are.
To eliminate the problems of the masking dilemma, testing should be conducted
using ER-3A insert earphones. These headphones are quite different than the
standard TDH style...rather than having cups than fit over your ears, the
inserts fit right into the ear canal using foam plugs that look similar to foam
noise protection. By using the inserts, the IA actually is greater (from 70+ dB
HL), so often the masking dilemma is eliminated for most cases of moderate
conductive hearing loss.
We use ER-3A inserts for all of our testing, and I have never come across a case
of masking dilemma using this type of headphone...
Kimberly A. Eskritt