REM question: how often does REM test reveal off-target gain?


I have a question about the REM test for the pros on this forum, and also for regular members on this forum who had the REM test done as part of their fitting:

For the regular forum members: When your REM tests was done, was the result significantly off from the target gain enough that would require your provider to make adjustment to match the measured gain to the target?

For providers: What is the percentage of REM test you’ve done where you’ve found significant enough deviation from the target gain that you’ve had to make adjustment to match the hearing aids’ gain to target.

The reason for my question, what started making me curious, is because my brother recently bought a KS8 from Costco and I asked him if they did the REM test for him. He said "Yeah, they did do that for me, but the guy didn’t make any adjustment or remeasurement. It was more like going through the motion to say that they did it, or that it was perfect the first time around."

In my last fitting a year and a half ago, I didn’t know what REM was at the time and it wasn’t done on me. Six months after that, I learned about REM online and on a return visit, I asked my audi why she didn’t do REM on me. She said that she’s found REM results to almost always show that modern hearing aids tend to match the target gain fairly well, so she stopped doing it and now will only do it as a sanity check if the patient seems to have problems with their hearing aids.

I know that in theory it should be done, and it is also good practice to do it, even if more often than not, it confirms and shows good result. So I don’t want to debate here whether REM should be done or not. I agree that it SHOULD be done, period. And next time I have a new fitting for a new hearing aid, I’ll insist on having REM done for me.

But what got me curious is how valid that excuse is, that "I don’t do REM because it almost always shows good result, so I think it’s a waste of time and I only do it on patients who seem to have troubles with their hearing aids."


I do REM at time of purchase, demo, annual review (transducer gain can drift over time, hearing aids can malfunction in ways difficult to detect without REM), or if something odd is going on. So, frequently. I run test box measures regularly as well.

The other day my first fit was absolutely perfect and I snapped a photo and sent it to my colleagues. That’s how infrequent a perfect first fit is–that it is notable enough to share.

That being said, the majority of first fits (maybe…60%?) are close. And unless the ear canal is a bit atypical, manufacturers tend to deviate (in my experience) from prescriptive targets in a standard way such that after a while of fitting X device, I expect in advance to make a particular adjustment to it right away. First fits, at least with the manufacturers I majority fit, also tend to be better if RECDs are inputted into the manufacturer software. First fits are off-target in different ways depending on which prescription is used. Lately manufacturers have also been adding a user experience function (ugh) which will effect the first fit, generally by dragging the gain down overall and preferentially at higher frequencies with the idea that users should be given gain slowly (a theory I find questionable, but very common in the industry). This is neither here nor there so long as the practitioner knows what’s going on.

A solid minority of first fits are way off. A VERY small minority of new hearing aids are lemons.

As per your brother’s experience, I’ve heard similar complaints from American audiologists that (American) Costco practitioners run REM because they have to but do not know what to do with it. Could be sour grapes, I don’t know. But there have been practitioners even here who refer to prescriptive targets as “arbitrary”, which suggest that they don’t have a strong understanding of their purpose and utility, or a strong understanding of evidence-based practice.

And there lies my own bias. If a medical professional dables in naturopathy, chiropractics, acupuncture or the like to bolster their business, I run the other way.


My audiologist upped the gain during REM testing on my Phonak and ReSound fittings. On the Phonak fitting, the REM results also prompted her to swap one receiver for a higher-powered one.

The fitter has to get the mic really close to the eardrum for REM testing, while also juggling the hearing aid or in-ear fitting and not displacing the mic. High chance of patient discomfort and reaction. I can see why some fitters wouldn’t want to go there.


The speech mapping or REM may be “close enough” to satisfy the practitioner but is “close enough” the best you can get, probably not. Close only counts in horseshoes and hand grenades and is a disservice to the patient if used in fitting. It really only takes a few minutes to fine tune a fitting from “close enough” to really close.


My experience at Costco supports that claim. REM was run and it was “close enough.”


Oh come now, getting hit in the eardrum with a probe tube doesn’t hurt THAT much. Having practiced on eachother in school, I’ve probably been hit in the eardrum some 30 times by hamfisted amateurs. :rofl:


Yes, Volusiano. On my trial of the Oticon Opn2, I had REM done and my provider had to make significant adjustments right off the bat, mainly in the high frequency ranges.

I didn’t know much about REM either, but I learned how important it is by watching Dr Cliff Olson’s videos on YouTube. I now tell the practictioners that I know what REM is, and I request that it be done at various intervals to be sure that the HAs are providing the prescription I need.


Thanks everyone for your replies so far.

I guess I have some follow up questions:

  1. Beside insisting on having a REM done, should a patient go a step further and insist of seeing the REM result to see how far off (or “close enough”) from the target it is? For example, what if somebody at Costco did the REM test on you perfunctorily and said nothing and moved on with the programming part? Do you let it slide?

  2. Would the provider be justified to take offense if they say it’s “good enough” but you ask to see it anyway?

  3. If the provider says it’s “good enough”, do you just take his/her judgement and leave it alone? Or should you form your own judgement? And what is the 'good enough" criteria? Within 5 % deviation? 10%? 20%?

  4. What is the frequency range where you expect the result to match the target closely? The point of this question is that there are probably limitations preventing adjustments to match closely at the extreme highs and/or lows. So what are the cutoff frequencies on the high and low where you’re supposed to give up trying to match the target because it’s not realistic to expect the hearing aid to be able to match it beyond that range?

  5. Should you insist on REM being performed each time your fitting is changed, like going from one dome type to another or to custom molds, or going from one receiver size to another?


During my fitting for my Costco ReSound Forte 861 RICs, the hearing aid specialist did indeed perform a REM test. For both aids, there were significant performance shortfalls in the middle and upper frequencies. The specialist corrected these by dragging the aids’ performance curve upward to match the prescribed level. Had this adjustment not been made, the aids would not have met my needs and I am certain I would have returned them.



I basically went into my provider with a little knowledge about the REM test, so while it was being done, I asked a lot of questions, such as “Oh, so that line is supposed to meet/overlap this one?”, etc. As a result, my provider started to explain what he was shooting for with the adjustments, and, throughout the process, he could see that I was watching what he was doing. I think that helped. When he finally said “good enough,” the measurement lines did actually match up pretty closely, so I think that engaging the provider while the test is being done and showing that you have some understanding of the test might help. Oh…and I asked my provider about how often the test should be repeated, and he said with any major change–be that changing the type of hearing aid or a change in hearing, etc. He also said it could be done periodically to make sure the targets are still being met.


Eh, there is some skill in knowing what affects the REM and when to worry about things being off and when not to worry, and how an individual patient’s experience affect things. You’d be better off asking your practitioner to explain their reasoning than demanding a particular outcome.

Pediatric fittings are nice because you have an occluded ear (and you run the audiogram, the RECD and the REM all through the same mold so you have a standard coupling to the ear, reducing variability), you can fit the hearing aids precisely the way you’d like because they won’t complain about their voice sounding different than they are used to or the dishes being too clinky, and you have nice outcome measurements such as language development. In pediatric fittings, you’re aiming for a deviation from target of less than 5 dB RMS at .5, 1, 2 and 4 kHz, and commonly you can get under 2. (The struggle then is just getting the parents to actually put the hearing aids in because, as you might imagine, an infant with 4 hrs a day of language experience doesn’t do as well as an infant with 12 hours a day of language experience.)

But generally you are right in imagining that you should almost always be able to hit the targets in the middle, and the ones at the edges might have to be sacrified more or less depending on the fit of the hearing aid, the level of the hearing loss, the shape of the hearing loss, and the patient’s tolerance and motivation.

Definitely REM should be performed if the power level of the receiver changes. You are basically re-fitting hearing aids from when you change the receiver. Dome, not necessarily.


I had REM done recently at Costco after the HAS said it almost always matches. It didn’t match on one ear and she did make adjustments as a result of the REM test.


I am in agreement with Neville…I have been using real ear verification for 33 years…I have found the manufactures first fits works less then 2 percent of the time. But this will depend on what the audiologist/hearing aid dealer decides what is “adequate” for target match, Having work with all the manufactures at last one time or another, none of them have the “magic bullet” software. The hearing aids need professional involvement if…and that’s a big if…the consumers wants their residual hearing utilized to the fullest. For me, I prefer the gain graphs to be close to target (I use NAL2R for most losses except for mod/sever to profound then i used NALR. I have found the manufactures REM formulas rarely work well enough to use them). Taking into account the ear canal resonance (which can differ between ears), provides better sound quality and benefits. Once you start with the manufactures first fit and then match target, the patient reports better over all hearing. The was apparent when my REM equipment was down and i had to use the first fit ( with some blind adjustments) and then re fitted on follow up with REM. The patients overwhelmingly reported better sound quality and understanding. In addition I have seen some really strange response from the first fit software of manufactures (this also goes for mail order and OTC aids) when the patient ear canal and acoustic come into play with hearing aids. So unless the practitioner uses some form of objective verification, they are just shooting in the dark and relying on the subjective description of the patient, which has a high variability among patients for various acoustic events. And I agree with Neville on this:


In addition, the number of bands/channels are not as critical as the frequency of the bands and channels (note that the frequencies of the bands the manufactures report are not always what the REM shows when you adjust nor the amount of gain you want). For me I prefer a few inter octave bands in addition to the octaves…as i always find 750 Hz, 1500 Hz, 2500 Hz, 3500 Hz, 4500 Hz, 5000 Hz, and 6000 Hz will be compromised due to canal resonance, ear canal shape and acoustic coupling. But how will the audiologist know unless REM is administered.


Are you saying that some patients knowingly don’t want this? Or are they unaware that they’re not hearing as well as they could?


I went in a couple of weeks ago to have my REM test done. I will have to ask him to email me a copy of the result, so I can upload that.

From memory, he had to boost low frequencies in both ears and increase some of the higher frequencies in the right ear. I think he must have reduced some of the higher frequencies in the right ear as well.

The result is that I can hear better in the left ear - not as soft as it was and the right hear does not sound as sharp/shrill as it used to when watching movies.

From memory, I don’t think it was massively off, but the difference is noticeable in terms of volume in left hear for using the phone and its not shrill anymore in right ear. One thing that I have also noticed is that the right hear is now noticeably louder than the left ear. I think because he increased the lower frequencies in the right hear and reduced the highest frequencies for the right hear, the volume differential (which has always been there) is more noticeable.

I think the volume differential and the fact that I still have issue hearing on the phone with the left ear is more down to the dome leaking bass as I have a much bigger dome in the right hear than the left ear. I am creating a new topic for the left/right volume issue so as not to make the REM topic go off topic.

The REM has helped though.


The REM has always dictated some substantive adjustments to get me to my prescription.


New HA user (close to 2 weeks in use) I asked about REM (learned about here and Dr. Cliff’s videos) after having to make an unscheduled trip due to L being what felt like getting rubbed raw in the canal. It was stated to me that we will do REM when we get to the full level of the prescription. (guessing that is what my provider is doing) From what I had seen on the P/C screen when I was fitted there were 4 boxes and she started me out on the 2nd box in the program. ( BTE Widex Evoke 440 F2’s)


Lol…REM is used in order TO properly meet prescription


There is merit in this approach though, there’s no point setting the REM target of the aid when you’ve just done the sensogram and you’re only on 80% of the nominal target per the acclimatisation…

REM validation is a great tool, but if you lose your ability to be flexible or simply ignore the client’s input, you’ll end up with a patient who is dissatisfied in he short term and can reject their hearing aids.