Why Bone Conduction Tests Never Exceed 4 kHz?

My bone conduction (BC) tests never seem to exceed 4 kHz. My first diagram indicates bone conduction on 250, 500, 1k, 1.5k, 2k, 3k, 4k. The second diagram from the second test indicates BC at 250, 500, 1k, 1.8k?, 2k, 3k?, 4k. (The frequency was a bit harder to read on the second diagram, but that may be 1.5k and 3k. I presume those are the standard frequencies.)

First test:


Second test:


I just checked the specs for one of the Otometrics PC based audiometers (Madsen Astra 2).

I don't know exactly what kind of headphones or transducers were used. But I do know that my first test was done with "OTOsuite" which indicates Otoacoustics software was used. The second test was done with "Equinox" which indicates Interacoustics software was used.

So if the BC transducer can go as high as 8 kHz, why did neither of my BC tests exceed 4 kHz? Especially in my case, where I obviously had a mild threshold dip at 6 kHz by air conduction (AC)?

Would it not be necessary to test BC at 6 kHz in such case? My analytical brain tells me that such a test would be absolutely essential! In order to differentiate between conductive and sensorineural hearing loss.

Am I asking too much here? It's probably just a matter of two or three more mouse clicks on the computer on part of the operator, and no more than 1 minute longer examination. Is that such a big deal?

You know I get the feeling that audiologists are a bunch of laymen... so unprofessional and careless! For my first test - which was my first encounter with an "audiologist" - they wanted to skip the BC test entirely, or at least for my left ear (don't remember if they had already done the right ear). You know why? Because the operator had difficulties putting that thing on me, it kept slipping off my head. So she wanted to skip that, like a real professional amateur. Despite the fact that it was my left ear I came in for and had problems with.

Just out of curiosity, have any of you had a BC test that exceeds 4 kHz?

Note! BC is indicated by the left angle and right angle brackets. Blue for left and red for right ear.

 

I probably should not have used the word "never" in the title. I just checked the thread where members put up their audiograms, and there appears to be one member from Dubai who seems to have had a BC test up to 8 kHz. Please have a look at that for a second opinion. But the prevalence is that most members (of those who posted their diagrams) never had a BC test beyond the 4 kHz mark.

Many of these diagrams are plotted on a template paper by hand. That's most interesting! You would expect audiologist and ENT clinics to have invested in a computer printer and diagnostic software that allows printouts by the year 2010 - 2016 (for older and more recent tests). This makes the reading of these diagrams that much more difficult.