There is a pretty good but getting old thread discussing the various fitting formulas. Here’s a link to the 2nd comment rasmus_braun made in the thread (see also his previous one above in the referenced thread):
Thanks for the link Jim!
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BTW. I asked my audi today her take on what the difference was between the ReSound proprietary Audiogram+ (based on NAL-NL2) and the NAL-NL2 & DSL algorithms.
She said there is more compression in Audiogram+ vs. the other two algorithms and likened it to the difference between progressive bifocal glasses vs. straight bifocals (no gradation). She said with Audiogram+, there’s more of a gradual bump up in gain as the volume changes whereas with the other two “it all jumps up,” which might be too much for some people.
Don’t know the rightness/wrongness of her analogy but I thought I’d offer it for discussion and hopefully learn lots of additional good stuff from you all in the process if there’s anything right or wrong in her comments worth discussing.
I’m not buying it. I think there are company fitting formulas solely to increase comfort and reduce returns.
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Don’t know the rightness or wrongness of more compression - but I did think she was telling me that Audiogram+ was designed to be more comfort, fewer returns from users - but the best thing she told me is that if I wanted to be a DIY’er and fire away substituting NAL-NL2 or DSL for my fitting, as I told her, was to go for it - that she was happy to have me experiment and actually wished the opportunity was available to more users (maybe less follow-up work, less “free fittings” by the provider? - but I shouldn’t be cynical - she a marvelous audi at least as far as customer relations go and I’m glad that I got hooked up with her - particularly after getting a thumbs up for DIY’ering (or whatever!)-particularly that if I stayed within the limits of the fitting software guidance on switching algorithms, etc., that I was unlikely to damage my hearing.
Update:: Here’s a ReSound Blog discussing NAL-NL2 vs. Audiogram+ (not meaning to take discussion too far off topic of NAL-NL2 vs. SmartFit). Perhaps both my audi and Don are both correct. The blog basically says as a “first-fit” Audiogram+ is designed for user comfort and found to require somewhat less fine-tuning after the initial fit than NAL-NL2 for user satisfaction. But also seems to be saying Audiogram+ tries to avoid too much gain, Audiogram+ compresses everything DOWN whereas NAL-NL2 is flatter with more gain allowed across the range of amplification (my experience from looking at my target output curves). Says no matter what the algorithm there are problems arising at the ideal fit that satisfies the user (fine-tuning required, doesn’t mention REM). There is some discussion of NAL-NL2 vs the NL(1) version. The blog is from 2014.
It is probably hard to generalize the manufacturer formulas. They may all take a different approach. When I compare the SmartFit Power to NAL-NL2 there are some obvious differences. The NAL-NL2 is smoothed out. So there are areas where it under corrects compared to SmartFit, and other areas where it over corrects. SmartFit follows the hearing loss much more closely. And in general the NAL-NL2 boosts the quiet sounds more and the loud sounds less. In other words more compression.
OK, I have had my aids REM checked by my Audiologist on NAL-NL2 for P1 and Oticon VAC+ for P2.
The REM check showed that I was very close on my fitting with my adjustments. So that the new fitting results are very much the same as I previously had.
Therefore I am sticking to NAL-NL2 for better speech intelligibility (at least for now!).
NAL-NL2 and DSL are both evidence-based prescriptive formula with slightly different ideologies.
Manufacturer fits are secret mysteries, mostly based on some version of NAL, but must in the end be driven by patient acceptance rates.
But both checked against NAL-NL2 targets.
Okay, I have a sort of dumb question;
Am I correct in my understanding that REM is performed AFTER acclimation to HA’s?
I’ve had my HA’s for about 5 weeks now & My audi has REM available, but hasn’t done it yet.
When should I be pushing to have REM done?
Dave
No Neville, NOT BOTH checked against NAL-NL2.
My aids are set as follows:
-
Program 1 is “General” programmed to NAL-NL2 target and corrected with REM to NAL-NL2 target; and
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Program 2 is “General” programmed to VAC+ target (Oticon) and corrected with REM to VAC+ target.
That allows direct comparison of fitting rationales with “the flick of a switch”.
Genie 2 Programming allows for different programming rationales on each Program setting.
I was just confirming my preference for NAL-NL2 for superior speech ineligibility over VAC+ after I had my Audiologist do the REM testing and verification and necessary adjustments for each Program on my aids.
I am just a hearing impaired enthusiast. So I will give an answer that I think is correct. Please, any better qualified Member should feel free to correct any of my mis-perceptions.
REM is conducted at the end of the fitting to confirm that the correct amplification for your audiogram prescription is actually heard in your ear canals. Adjustments are then made to enhance or reduce different frequencies to fit your hearing loss.
REM in essence corrects the receiver output to confirm and if necessary correct for different volume size and shape of your actual ear canals against the “standard ideal average model of an ear canal”.
To directly answer your question, yes, REM should be done immediately after fitting your hearing aids.
Look at Real Ear Measurement and Fitting by Doctor Cliff on youtube for a fuller explanation.
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Verification systems do not have VAC+ targets. So even if your hearing aid is set to VAC+ programming, if you are doing REM you have to choose targets to compare those settings to. Since you cannot choose VAC+ targets (they are proprietary), you have to choose something else to compare them against.
I don’t think I have been able to explain this clearly in the past when I’ve mentioned it, and maybe I’m not explaining it clearly here.
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Hi Neville,
I only know what I think I know (which can be dangerous!).
So I must defer to your greater knowledge on the subject.
Best regards…
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Neville, 2nd page of this https://www.oticon.com/~/media/Oticon%20US/main/Download%20Center/Opn/Product%20Information/12241%20-%2015555-10026%20Real%20Ear%20Cookbook.pdf
suggests that Genie2 has REM Autofit that allows verification against VAC+. Is this not “real” REM?
Yeah, that’s something I talked about with someone else, and the answer is: I don’t know. I’ll have to find time to hook it up and play with it. The text certainly suggests that it does, doesn’t it. I did not think that autofit was widely used yet though.
I still feel a little uncomfortable about it. Nice that the software will tell you that the hearing aid is doing what they intended it to do, but you still cannot verify that independently.
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My understanding is that the REM test is done when your hearing aids are fitted. All they are doing is measuring with a microphone inside the ear canal how loud the sounds are from the hearing aid speaker. The computer program predicts how loud they will be, but each ear is different and only when you measure the sound level directly do you know if the correct sound level is being applied. Ideally it should be done at soft, medium, and loud sound levels. It is not a test of your hearing, but a test of your hearing aid performance in your ear.
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The fitter at Costco tried to make the AutoFit in Connexx 8 work so they could measure REM to SmartFit formulas. She could not make it work. I suspect it can work, if it is set up properly. She said she was going to ask the Rexton rep about it when they come in.
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Thanks, now I’ve got a better understanding of REM.
Dave
Signia have a good tutorial on how to use their version of AutoFit in the link below. This was pretty much the same procedure and equipment that I saw with my REM fitting with my Audiologist using the autofit feature of Genie 2.
I am fairly sure that the fitting rationale was selectable and part of the prescribed targets on the Genie 2 as well…? It certainly was what I asked the Audiologist to do for me.
https://www.signia-library.com/scientific_marketing/autofit-imc2/
Signia is not compatible for us, unfortunately. My clinic is all verifit 2 REM machines. I think the Oticon autofit is compatible, I just haven’t had time to hook it up and run the appropriate checks.