I currently use hearing aids from both Oticon and Resound and both are fitted to the prescription formula. However, I’ve noticed that these hearing aids have different gain targets, especially in the higher frequency range
Gain target Resound (dotted line):
Gain target Oticon (dotted line):
As you can see Resound shows a more curved gain target compared to Oticon. Somehow Oticon has a higher gain target in the higher frequencies.
I’m curious about why there’s such a significant difference in gain targets between these two brands, given that both are following the NAL-NL2 prescription formula. Shouldn’t NAL-NL2 result in similar gain targets regardless of the brand of hearing aid?
Manufacturers use the standard algorithms but put slants on them. How they work best with the specs of ‘their devices’
Also take into account the coupling - the type of dome or mould you have. This changes the targets in the software. Each manufacturer has their own calculation of the ‘effective venting’ of their domes. Even if you have an ‘open’ dome from both manufacturers they might have different ‘effective venting’ and manufacturers might use this to influence the NL2 algorithm in different ways
Do you have a more powerful receiver on the Oticon aid?
When I look at your pictures where the frequency amplifications are, I am a little surprised that there is such a big difference. For example, if you insert an audiogram that is made in the clinic, then it will not be the same as in the hearing aid. If you do it IN-situ then the amplification will be as it suits your hearing.
Or maybe I’m looking at something wrong and concluding.
also with the Resound, I see the upper right gray field, which makes me conclude that it can’t amplify as much as the Oticon. Maybe you should use a stronger receiver and only then compare?
also with the Resound, I see the upper right gray field, which makes me conclude that it can’t amplify as much as the Oticon. Maybe you should use a stronger receiver and only then compare?
I have tried both the 85 and 105 dB speakers in Genie 2 with various dome settings. All result in the more or less same gain target. I’m unable to replicate a more curved gain target similar to Resound with Genie 2. It seems that Oticon really amps up the higher frequencies compared to others. Interesting.
I’m curious about why there’s such a significant difference in gain targets between these two brands, given that both are following the NAL-NL2 prescription formula. Shouldn’t NAL-NL2 result in similar gain targets regardless of the brand of hearing aid?
Did you specifically select to be the prescribed fitting rationale in the program that is showing the gain curves above? It doesn’t matter if your adjusted your gain curve to fit an NAL-NL2 target, if the program you’re looking at has the proprietary fitting rationale chosen, then the prescribed target gain curve you’re looking at would be based on THAT fitting rationale, not the NAL-NL2. You can’t just assume that just because the HCP did against NAL-NL2 that what you’re seeing now is the NAL-NL2. It must be select as such in the programming software in the first place.
Just want to get this clarified so that we can rule that out first before making any kind of analysis.
My sincerest apologies! I thought Resound was , but it seems I was too tired yesterday. Upon rechecking everything after your post I found out that the Resound gain target was NAL-NL1.
When inserting this in Genie 2 I get the same curved gain target:
Glad to hear! I hear that clinicians tend to do adjustment to targets, from a conversation I had with @Neville. It makes me wonder when REM is done whether most clinicians would ask their clients which fitting rationales they would like to target to. But then I can understand that it’d be too much of a technical question to ask a typical client in the first place. I wonder how they choose which fitting rationale as the target. I’m just guessing here that NAL-NL2 is more recent than NAL-NL1 (but I can be wrong, they may just be different). But if that’s the case, I wonder why a clinician would pick NAL-NL1 over NAL-NL2 to do REM on?
Once a hearing aid company has licensed the , they are allowed to make alternations, and can still call the algorithm “NAL-NL2.” What has been common practice over the years, therefore, is for most if not all manufacturers to alter the NAL algorithm to more closely resemble their proprietary fitting—that is, significant gain reduction in the higher frequencies, especially for soft inputs, beginning ~2000 Hz. It’s common that this reduction is 6-10 or more. Hence, while the fitting screen may show a “fit-to-NAL” it is not a fit to the real NAL, and it is unlikely that the patient will not experience the same degree of benefit.
NL2 is the standard as you said but sometimes it’s best for the wearer to use a different formulae. Depends on their history, and also factors such as the shape of the hearing loss
s done whether most clinicians would ask their clients which fitting rationales they would like to target to. But then I can understand that it’d be too much of a technical question to ask a typical client in the first place. I wonder how they choose which fitting rationale as the target. I’m just guessing here that NAL-NL2 is
Doesn’t Genie 2 pick a fitting rationale based on the intake questions (“Personalization”)? I get the impression that experienced users with heavy losses get while the inexperienced with light losses get VAC+.
And a good question! I’m wondering the same. This was done by an experienced audiologist in an academic hospital. The only reason I can think of is that I was using power domes, so -NL2 would be more prone to feedback due to more enhancement in the higher tones
It gives me better Speech in Noise and better Bluetooth streaming Altho since my hearing dropped, background noise is so muted that I probably need to look into changing fitting formulas.
I don’t have any fancy features on like NoiseBlock and what ever it’s called with Oticon. All features are turned off.
Since hearing dropped tho, background noise is so extremely muted tho I don’t like it even when all the fancy features turned off.
Speech is also extremely muted now since hearing dropped.
Doesn’t Genie 2 pick a fitting rationale based on the intake questions (“Personalization”)? I get the impression that experienced users with heavy losses get NAL-NL2 while the inexperienced with light losses get VAC+.
The manufacturer will almost always pick their own proprietary fitting rationale for their hearing aids over the standard rationales, because they think that their own rationale works best on their hearing aids. Otherwise, they wouldn’t bother coming up with their own in the first place.
The Personalization intake questions affects various settings inside Genie 2 but not the selection of the fitting rationales. The characteristics of the different fitting rationales is very subjective, so one cannot really make a hard definition of what the rationales are like in order to assign the personal preference to a rationale. For example, if you say you like bright sounds, how would Genie 2 know to if it picks for you that that rationale would be bright enough for you? What if you find v5.0 Adult brighter than NAL-NL2 (which I personally do), and Genie 2 still picks NAL-NL2 for you? It’s better for Genie 2 to stick with VAC+ and increase the brightness control (the higher frequencies) gains than to arbitrarily decide which rationale is “bright” to your taste.
Note, however, that even if you have VAC+ in your default P1 General program, if your makes adjustments for you based on an NAL-NL2-based target, then your REM adjusted gain result will now sound more like the NAL-NL2 rationale than VAC+, even though its base fitting rationale is VAC+ based.
That “can” be part of the reason why seem to show to be “underperforming” when REM is done. The proprietary VAC+ (or whatever it is) rationale may not be designed to sound as bright as NAL-NL2 by design. So if your HCP tries to match a VAC+ based gain curve against the NAL-NL2 target curve, the VAC+ based gain curve may show to be underperforming in the highs compared to target, not necessarily because the Oticon HAs are bad and can’t amplify up-to-snuff per se, but it could partly be because the NAL-NL2 target curve is already stronger in the highs compared to the VAC+ target curve simply by the nature of its design.
Yes, that’s true. It applies to Oticon Genie 2 as well. If you go to Preferences → Fitting defaults, you can change the default to , for example. Then for a brand new client, the default General P1 program will show up with NAL-NL2 selected.
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