I have the gain/insertion profile performed with REM on my ha. Is it equally valid if I replicate the curves on a different manufacture’s ha?
I am not professional, but it’s better to always have current results (I am Cpt. Obvious here, I know).
After thinking about it for a while, assuming anatomy of your ear didn’t change since last test:
REUR - it is without any HA on ear, so theoretically it could be relevant for next tests
.
I would be very cautious about other parameters:
REOR - requires the same acoustic coupling as with previous HA, assuming it was RIC/BTE.
REAR - better NOT to transfer because of different HA tested in that .
NOTE: If new REM is performed (especially with different device) it’s better to proceed new ALL tests.
Someone could correct me if I am wrong.
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Put simply,no you won’t get the “exact” results on other HAs, you won’t even get the exact results on the same HAs on any given week, yeah not sure why this would matter anyway, if you move onto another brand you’ll start with a complete new fitting.
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Not to mention that a different manufacturer uses a different proprietary prescription. That means you’re starting from an entirely different baseline (unless both hearing aid adjustments were set to a universal fitting forumla such as NAL-NL2 or DSL). How exactly would you replicate the gain curve on another manufacturers software? I really see no way of doing this with any degree of accuracy. I’d suggest performing REM from scratch. There are just too many variables at play here.
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The reason behind the question is that having got a fitted REM profile with Nal- nl2 on my ha if I buy another make online then I can replicate the gain profile without having to get an audi to do another REM.
I can match the REM profile on another make with their fitting software – so it should be like a fitting transfer. From what tankan says the REMs are not exactly reproduceable anyway so I thought this would be a good start on a new make. But am I wrong?
Yeah? No.
The point about REM is that it’s measured against a given stimulus.
The reason you have it done is to deal with the manufacturer’s estimate (guessing) you see on screen. So no, as that original REM doesn’t include the new assumptions, gain levels and idiosyncrasies of the new fitting.
Now, if you want to talk about RECD (Real Ear to Coupler Difference) then you might have a path through this that would work. REM’s are only accurate if conditions under which they were measured are repeated. Changing any element (especially manufacturer) throws all that out the widow.
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All correct: the only one you’d actually want/need is the REAR anyway. As that’s the one that gives you the total output with the aid in situ.
So, the one that’s most impacted by changes in the test situation is the one that’s most relevant in terms of the fitting.
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Period.
@Um_bongo , thanks for clarification 
So are you saying that I should replicate the Output-SPL Real Ear profiles rather than the Gain Insertion Gain profile to effectively transfer the fitting to a new model? Thank you
No, all of it becomes invalid (unless you’re using the same aid, receiver, mould/dome). Kneepoints, compression ratios and MPOs will all be applied differently. Yes there will be similarities of gain at specific crossover values, but you can’t ‘see’ that without an objective measurement.
Even if you switch programming rationales, you should run it again, simply because the basic premise of if you put X in, you’ll get Y out; doesn’t apply. The impedance of your eardrum/canal isn’t linear - nor the response of your ossicular chain or cochlear, especially near your canal resonance.
However, if you can clearly hear better in a given environment with the newer settings, that doesn’t mean you’ve made a mis-step, just that you haven’t verified it.
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Thanks for the clarification. The fact is that I have tried replicating the REM gain profiles in another ha with reasonable results but I can find no difference in performance using first fit or REM settings. But I keep coming back to REM settings because they are supposed to be the best.