Issues with Widex Inteo Hearing Aids

Recently I was fitted with an Widex Inteo CIC hearing aid. One of the main reasons that I chose that aid was that the specifications indicated that it had a very high maximum gain (61 DB using the ear simulator results) as compared to most other CIC aids that usually have a maximum gain of no more than 45 DB.

http://widex.com/is-bin/intershop.static/WFS/Widex-COM-Site/-/Editions/Root%20Edition/units/Widex-COM/Syndicated%20Content/Widex/COM/Media/Inteo/PDF/UK/IN-CIC_datasheet_UK.pdf

I wanted the high gain since I was fitted with a Siemens CIC aid about 5 years ago but I couldn’t see any difference in my hearing ability.

Between the frequency range of 1000-3000 Hz, I have a hearing loss of about 70 DB.

When I tried the Widex Inteo CIC aids, my hearing improved in many situations (I was much happier with these aids than with the Siemens aids) but was still far from perfect. I started to investigate how the aids were performing. I used the following program to determine how the aids were performing.

http://www.phys.unsw.edu.au/jw/hearing.html

I connected a high quality cupped headphones to my notebook computer, closed all the windows, and turned off anything that would make noise. I plotted my hearing (both without and with hearing aids) by clicking on the lowest possible DB on the chart for each frequency until I could no longer hear the sound. I repeated that process many times over many days to make sure that my readings were as accurate as possible (all graphs were almost exactly the same). Since the chart is not calibrated, I needed to figure out a way to calibrate the graph chart. Since my audiogram from the audiologist indicates that my hearing declined about 70 DB between 1000-3000 Hz and my Test graph (without aids in my ears) indicated about a decline of 42 DB over the same range, I calculated that each increment of Test graph indicated a 5 DB change instead of 3 DB as indicated on Test graph (70/42*3).

Although this test is not as accurate as the audiogram taken at the audiologists office, it should be accurate enough for what I want to determine.

Now I calculated the DB difference between each of the frequencies on the graph that was produced without my hearing aids and the graph that was produced with my hearing aids in my ears. I was surprised to see that the gain indicated was only 20 DB at 1500 Hz, 20 DB at 2000 Hz, and 25 DB at 3000 Hz but the gain at 4000 Hz was 40 DB and the gain at 6000 Hz was 60 DB (this did not even show on the graph without my hearing aids).

I said “what is going on here”? I reran the tests over and over again but the results were always the same.

If the resulting gain was about 40 DB, I may have suspected that marketing was advertising fiqures that weren’t accurate. But at only a 20 DB gain, that would be a major stretch even for most marketing people.

I also noticed that the fitting range did not match the increase in gain (indicated a maximum of 75 DB and should indicate a maximum of 85 DB) due to the following statement from the Widex documentation.

The maximum available gain is substantially increased. Indeed, the Multi-directional active feedback cancelling yields an average of 15 dB more usable gain - SuperGain - before feedback occurs.

So I asked myself, what is the problem? Why is the fitting range so low? Why is the fitting range 75 DB instead of 85 DB? Why is the gain only about 20 DB at 1500 Hz, 2000 Hz, and 3000 Hz? Why can frequencies at 6000 Hz produce a gain of 60 DB? Is the gain reduced for some frequencies due to feedback? Is the problem caused by the channel design? Did the audiologist set up the aids incorrectly? Is there a design problem in the software? Is it possible that my ears are so damaged at some frequencies that a 60 DB increase in SPL (sound pressure level) will not produce a similar response in my ear?

I’m stumped. Does anyone have any ideas? Has anyone had their hearing tested with their aids in the ears? If you did, what were the results as compared to your original audiogram?

I’m going to see the audiologist on Tuesday so I’d like to determine what I should do. I’d like to determine if I should try another brand of aid but if they all act similarly, it would be a waste of time.

Will open fit hearings aids work significantly better even though their maximum fitting range is at most 80 DB (some are as low as 70 DB) and have a lower maximum gain than this aid?

" I was surprised to see that the gain indicated was only 20 DB at 1500 Hz, 20 DB at 2000 Hz, and 25 DB at 3000 Hz but the gain at 4000 Hz was 40 DB and the gain at 6000 Hz was 60 DB "

I didn’t follow the site you posted all that well…its seemed like it wanted to
normalized the loundness at each frequency and that it should fall around
one general dB number for all frequencies in a close range (1kto5k)??

That said, if you found the dB gain of your aid was different at different frequencies wouldn’t that indicate the way it was programmed…ie you found
it’s programmed to make higher frequencies louder (60dB, validating the
fitting range/specs) and lower frequencies were amplified less (20dB) ie… the aid is doing what it’s suppose to?

But perhaps I misunderstood.

dear mike:
I can help you, to see what the problem is…
it seems to me that you are trying to find a way to validate or proof your fitting. Unfortunately, many of the modern hearing aids (certainly the inteo)
contain features such as feedback cancelation, noise reduction, etc. which
did not work well to measure funtional gain (ie: how much gain the instrument provides). The only way to do this is using realear measurement - which
in this test youy can view all at once, your hearing loss, the input signal
the amplified signal and the unconfortable level. Generally a special tone (which is speech like) is used as an input. Several REM have a target for a fitting formula so you can see how close the aid is actually performing vis a vis the fitting target…

WORD OF CAUTION.- some high end hearing aid contain specific fitting formula so target matching is not really acheive, it is perhaps bet to test 3 signal, one normal speech one soft and one loud and compare how it fits in
with in your dinamic range… if there is a deviation she/he will be able to fine tune the instrument. This procedure takes some time so be patient and cooperative

This is why its important to have an audi… and perhaps the reason
why you buy @ a dispensing office vs internet


Toyota Celica Gt-Four History

I think I figured out why the Widex Inteo CIC aid is working differently than I thought it should. It now appears that it is basically working the way it was designed.

All hearing aids develop maximum gain at their lower input SPL (sound pressure level) and that gain is reduced once the input SPL reaches what is known as the compression kneepoint. After it hits the copression kneepoint, the gain will be reduced by the compression ratio (ex. 2:1 compression ratio will decrease the gain by 5 DB for every 10 DB increase in input SPL). The gain reduction continues until the input SPL reaches 90 DB. At that time, the hearing aid has reached its maximum output and will not produce any any higher of an output no matter how high the input SPL goes.

In the case of the Widex Inteo CIC aids, the specifications indicate that the output at input 90 DB SPL is 117 DB (the maximum output of the aid) and the output at input 60 DB SPL is 101 DB. Extrapolating these figures, we can see that the default compression kneepoint has already been hit at input 60 DB SPL (gain is only 41 DB) and that the compression ratio is approximately 2:1 (5 DB gain for each 10 DB increase in input SPL). If we further exprapolate backwards we can determine where the default compression kneepoint is. In this case, the compression kneepoint is at input 30 DB SPL.

Therefore, the following table is the maximum gain at different input SPLs for this hearing aid. I use a compression ratio of 2:1 but it is actually just a little less than that so the table produces an error of 1 DB at input 90 DB SPL.

0 input DB SPL produces a maximum of 61 DB gain.
10 input DB SPL produces a maximum of 61 DB gain.
20 input DB SPL produces a maximum of 61 DB gain.
30 input DB SPL produces a maximum of 56 DB gain. (compression kneepoint hit)
40 input DB SPL produces a maximum of 51 DB gain.
50 input DB SPL produces a maximum of 46 DB gain.
60 input DB SPL produces a maximum of 41 DB gain.
70 input DB SPL produces a maximum of 36 DB gain.
80 input DB SPL produces a maximum of 31 DB gain.
90 input DB SPL produces a maximum of 26 DB gain. (maximum output hit of 117 DB)

So how does the table relate to the test I performed?

The easiest to explain is the abnomoly that occurred at 6000 Hz that appeared to produce a 60 DB gain. A gain of 60 DB did not really occur at that frequency but instead a gain of only 20 DB. At 6000 Hz my hearing is very bad and for me to hear a signal, the input SPL has to be very high (my guess is 105 DB or greater). At input 80 DB SPL, a gain of 31 DB is developed by the hearing aid producing an output of 112 DB which I could hear. At input 90 DB SPL, a gain of 26 DB is developed producing an output of 117 DB. All other higher inputs SPLs (100, 110, 120, and 130) all produced the same output of 117 DB which I could hear. In reality, the hearing aid produce the same output for 8 of the 12 sounds that I heard during the test when I was clicking on the column for 6000 Hz. A similar abnomoly occurs at 4000 Hz but not as pronounced since my hearing isn’t quite as bad at that frequency.

Exactly calculating why frequencies between 1500 Hz and 3000 Hz only produce between a 20-25 DB gain is not as easy to determine. However, depending on the input SPL, the maximum gain will be anywhere between 26 DB and 61 DB. That is still more gain than what is being indicated by the test results. If the gain being indicated was about 40 DB (instead of 20 DB) during the test, this issue of reducing gain depending on the input DB SPL would probably explain the problem 100%. However, that is not the case.

So another explaination for part of the approximately remining 20 DB loss is that the maximum output (and therefore gain) was reduced for the channels when the aid was programmed to compensate for feedback. CIC aids are notorious for feedback if the aids are not perfectly fitted.

The final reduction in gain may be based on the specifications. I used the ear simulator results but there are also 2cc coupler results. The maximum output from the 2cc coupler results is 10 DB less than the maximum output for the ear simulator. Also, the maximum gain from the 2cc coupler results is 9 DB less than the ear simulator. This not only reduces maximum output and gain but it reduces the maximum gain that occurs at all input SPLs. I suspect that neither of the specification results are accurate as related to the human ear but the real world results are somewhere between the two. Otherwise, why would they produce both results?

If all of the above is true, that should explain why I am seeing such low gain with this hearing aid.

I don’t think that getting an open fit hearing aid will significantly help. They have similar gain and output characteristics and are also notoriously bad for feedback issues (gain and output are reduced to compensate for feedback problems).

One possible solution of getting an aid that is more powerful and is still cosmetically pleasing is to get an aid that is similar to the Phonak Micro Power.

http://www.phonak.com/com_datasheet_microPower_IX_300_dSZ-xx.pdf

http://www.phonak.com/com_027_0004-xx_micropower_ix_product_information.pdf

It has a high gain of 64 DB and a maximum output of 132 DB. It uses a thin tube with the receiver in the ear and the ear has a small custom dome to seal the ear from possible feedback.

With the maximum output increasing by 15 DB and hopefully feedback issues will be less allowing for about an additional 10 DB gain, that should give a total gain of about 45 DB during the 1000-3000 Hz range.

Some of you may wonder why I appear to be obsessed with the performance of my hearing aids.

First of all, marketing tends to overexaggerate the good points of a hearing aid (noise reduction, feedback cancelling, number of channels, etc.) but downplay the weak points (how much real benefit will be produced out of their hearing aids).

I can visualize what kind of performance I would like out of a hearing aid to be very happy about my hearing. Obviously a hearing aid that could amplify all frequencies to a normal DB would be the perfect hearing aid but that is only possible for some people with mild/moderate hearing loss.

To try to razzel and dazzel you, marketing uses gimmick terms such as Real Ear Sound, Digital Surround Zoom, Self Learning, High Definition Sound Analysis, High Definition Sound Processing, and Speech Enhancer to try to downplay the limitation of the amplification capabilities of the hearing aids.

Some features can help your hearing experience such as noise reduction capabilities and directional microphones but are only implemented because of the deficiences in amplification of the aids.

Feedback cancelling capabilities are the most promising new feature to improve your hearing ability but is still in its infancy. The reason it is so promising is that it is the only feature that is implemented to allow the amplification capabilities of the hearing aid to be increased.

Therefore it is quite important to understand how the most important features (maximum output and gain in a real situation) is performing. If those are performing well, your hearing experience could be greatly enhanced.

For every 10 DB loss of hearing, your perception of sound decreases by 1/2. Therefore if you have a hearing loss of 70 DB, your perception of sound is 128 times less than a person with normal hearing. If your hearing loss is improved to a 50 DB loss, the perception is still 32 times less than normal. However, decreasing the loss to 30 DB, your percetion of sounds is only 8 times less than a person with normal hearing.

Therefore if a hearing aid only amplifies your high frequencies by 20 DB and you have a 70 DB loss in those frequencies, you probably won’t see a big difference in your hearing ability since both of those losses still require a very loud sound for you to hear any sound at all. However, if the hearing aid amplifies those sounds by 40, 50, or 60 DB, the results can be truely remarkable.

During conversations, frequencies below 1000 Hz produce loudness while frequencies above 1000 Hz produce clarity. It is important that the frequencies above 1000 Hz are amplified to as near normal as possible for people with high frequency hearing loss to hear clearly.

So when I look at the test graph that I produced, I can now realize why my hearing has not improved as well as I hoped.

I’m sure an audiologist can assist me in choosing the correct aids but most of the information that he gets about aids comes from marketing material. He doesn’t have the time and maybe not the technical ability to study and understand all the different specification sheets.

Oh I see now what you were trying to measure now.

I do see for the Phonaks models you posted (BTE) the small size and thin
tubes. I must say they’ve really come a long way with HA size and tubing
these days. For myself my dispenser made me hard semi-transparent skin
looking molds. If it wasn’t for my large everday tubes you would not be
able tell I have BTE aids. Not that I care as an adult. As a kid I could have
sure used some small and discrete tubes and aids. With everyone walking around with bluetooth head sets
and earphones…my hearing aids and molds fit right in nowadays.

Hi,
I’m so glad that I’ve found your message. Since you are quite knowlegeable in this field, I would like to ask some questions. My hearing loss in 1000-8000Hz is about 69-70 dB. I have recently purchased a pair of Phonak Savia Art BTE 411 model which I was told is very powerful and among the best. I’m not very satisfied with them is the “speech in noise” program. The audiologist have adjusted and readjusted several times already. I still can’t hear well. In the data sheet I see the frequency range and TK (threshold kneepoint), G40, G60, G80 and MPO(max.peak output) and CR (compression ratio) in a table for every program. My quesion (1) do we set the CR or adjust the Gain e.g.G40,G60 to increase the gain for each frequency? Or adjust the threshold kneepoint to adjust ? Does the value automatically change when we adjust one variable ? (2) This CR is the frequency compression? (3) Does the so-called compression hearing aid has the feature of frequency compression ? Thanks for the attention.
Jene