I have severe to profound loss. Hearing aid companies are boasting about advances in feedback cancellation. Is a dome fit an option for me now?

Todd Gibson, AuD

Audiologist

06 July 2017 - 1.64K Views

You might be able to get away with power dome tip.  However, the most appropriate coupling would be a custom power shell that is encased in the receiver wire.   I use them all the time with very good success.  They are comfortable and can come in acrylic or soft materials as well. 

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Audiologist in London

06 July 2017 - 1.59K Views

A great feedback manager will never compensate for a poor fit. Simply put, some patients are a great candidate for a power dome and some others must have a custom tip to exploit the full potential of the hearing instrument. You may find frequency compression may also help to combat feedback. Also, not all hearing aids are not created equal when it comes to feedback managers some are better than others. 

So the answer is to try a dome if it doesn't work a custom tip will allow an even better fit in most instances and often access to more powerful receivers.

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Audiologist in Prairie Village

06 July 2017 - 1.6K Views

It's difficult to answer without seeing your ear canal or understanding your exact hearing loss but it's likely not appropriate for someone with a severe-profound hearing loss to utilize a dome tip.  Even with improvements in feedback cancellation, it's an acoustic issue and a power issue in regards to providing you with enough amplification for your best hearing.  There are custom options available however for different types of hearing devices that might be more cosmetic or fit more into the canal of your ear but likely if you pursue a dome type tip, you'll sacrifice overall hearing benefit.  It would be important for you to work with your trusted audiologist/provider to fully explore your goals and available options. 

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Ellen Nathan

Hearing Healthcare Provider

07 July 2017 - 1.57K Views

The short answer is no.  For profound loss, you really need that receiver to stay still in the ear to avoid feedback, angling toward the wall of the canal, etc.  I have not had good success with patients with severe to profound loss with instant fit domes.  You can get tiny canal molds that don't show at all, so if it is aesthetics  this would be a great option.

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Board Certified Hearing Instrument Specialist in Boone

06 July 2017 - 1.62K Views

Feedback cancellation has been addressed for years and some manufactures have done a better job with it than other. The biggest issue as a specialist is when it limits our ability to help the patient and several manufactures have fixed that. Feedback is sometimes seen in our office when we get patients from other clinics who don't custom fit molds for hearing losses that need custom made earmolds. We also see poorly made earmolds. These two issues can easily be helped by making great impressions of our patients ears. 

Technology is better but it cannot fully cover up poor or improperly fit hearing instruments. Make sure when choosing your professional you ask if they make custom molds and if so who do they use to make them. 

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Dawn Sanchez

Board Certified and Licensed Hearing Aid Specialist

06 July 2017 - 1.63K Views

Not really.  Severe to profound loss would be much better served with a maximum amplification mold fitting rather than a dome with RIC's.  Anti Feedback programming is very successful though but it would be easier for you to not have to deal with the touchiness of potential sound leaks and just go with a better fitting.

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Emma W
Emma W 16 August 2017
this! This is why I had lived in BTEs forever :)

Jack Adams

Audiologist

17 July 2017 - 1.55K Views

The answer is based on the shape and size of your ear canal as well as the degree of loss--are you closer to severe or closer to profound and is the canal curved or straight? These are the deciding variables. I have fit many patients with Power domes rather than molds with success, the dome can often provide better depth and retention than a mold and the speaker wire usually lays more flush along the edge of the ear.

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Keith Lam

Inventor, MBA-TM, BSET

10 July 2017 - 1.56K Views

Dear;

I would recommend you to go to a reputable HIS or Audiologist for help.  With technology such as frequency compression and feedback cancellation and occlusion reduction, there is quite a bit that an experienced hearing health care professional can help you with.  Pic someone who is familiar with Real Ear Measurements for the post fitting verification.  If you have been using analog aids, digital aids can mimic that too so just take the next step, go find out.  Most HIS do not charge for helping you unless you purchase hearing aids from them, so there is really nothing to loose. 

Good luck

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Sarah Chipman

Professional Member

06 July 2017 - 1.6K Views

It depends on your ear shape and your hearing loss.  If you have normal or mild hearing loss in the low frequencies, no more than moderate hearing loss i in the mid frequencies, and severe to profound only in the highs, and if your ear canal is somewhat straight and not narrow, then yes, you may be able to be fit with a dome.  If you have significant hearing loss in the low frequencies or severe in the mid frequencies, a dome will not hold enough sound in your ear to enable you to hear well, and you will still be better served by something that is custom shaped to your ear canal where you hearing care provider can control the size of the air vent to adjust the acoustics of the fit.  Feedback isn't the only reason to have an earmold or encased receiver: we want to be sure you can actually hear well with your hearing aids, not just avoid feedback. You can always try with your hearing healthcare provider, and it would be best if they perform real ear measurements to see what sounds are actually getting to the eardrum.  Thank you for the question!

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Steve Romeo

Professional Member

06 July 2017 - 1.6K Views

In a word, no. The problems with domes: (1) They move and change the acoustic environment inside the ear canal. At the levels required to provide correction for severe to profound losses, any small acoustic change can have a big effect on feedback. (2) If a dome does not move, then it is probably tight enough to be uncomfortable. 

The best solution is a custom shell with a power receiver embedded in the shell, connected to a RIC, or in extreme cases a power BTE with the receiver in the BTE, if you are willing to sacrifice smoothness and put up with increased distortion in order to hear. 

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Marvin Lewis, AuD

Doctor of Audiology

06 July 2017 - 1.61K Views

It's true, there are advances in feedback cancellation that have changed what types of hearing aids and earpieces we have been able to fit.  In regards to whether a dome fit is an option, I agree with the other responses that, " it depends".  What I can add to the other posts is that one of the many advantages of a custom mold is that it will conform to the shape of your ear canal and direct or aim the sound to your eardrum.  This is important because most ear canals have curves.  If you use a dome on a canal with curves, the sound may not be aimed directly at the eardrum, and you may not get the full benefit the hearing aid can provide.  However, if you have a relatively straight ear canal, it could work out fine.  Discuss this with your audiologist.  Do not stick anything in your ear to determine if your canal is straight.  Since you likely have custom molds now, you can look at the mold and see if the canal portion curves or is straight.  Also discuss your reason for wanting to use a dome mold.  Is it a comfort issue, does your canal retain too much moisture because of a tight fit, etc.  Again, discuss with your audiologist.  There are many things we can do to modify a situation, don't assume the way it is in the beginning has to stay that way.

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Mark Butler, AAS

Hearing Healthcare Provider

06 July 2017 - 1.62K Views

A dome fit might be an option depending on the shape of your hearing loss and the fit of the dome in your ear.  If you want to stay with the newer RIC style we can also use a custom molded power dome that will usually produce better results than the regular double dome.  You get the discrete size of the RIC style and the fit and seal of a custom mold available in several different styles and materials.  Lower frequencies require more power to reproduce so if you have a lot of loss in the lower end of the frequency range the RIC style may simply not be powerful enough to provide the amount of amplification you need.  The best answer is to find a hearing aid specialist or audiologist who knows what they are doing and have this discussion with them.  Our company offers a 60-day period in which you can switch styles or brands after your initial purchase with no additional cost (unless you trade up in technology level).  That would allows us to try the RIC product first and if we aren't able to make it work effectively then we could switch you back into either a custom aid or a BTE.

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Darin Scheurer

Professional Member

06 July 2017 - 1.63K Views

Maybe, but it depends on the level of your low frequency loss and whether we can deliver enough gain to be beneficial.  It takes a lot of power to deliver low frequency sounds.   As we raise the volume of the hearing aid, the sounds will bounce off your eardrum and try to escape back out your ear.   By occluding an ear canal to various degrees, we can raise the gain and reduce your chances for feedback.  Many of my customers also find custom molds eaiser to insert and more comfortable.   They can be made in any number of styles.  I recommend discussing the options and styles with your local hearing healthcare provider.  Good luck!

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Terese Huber, AuD

Doctor of Audiology

06 July 2017 - 1.63K Views

It depends upon several factors. Some manufacturers use gain reduction, others phase cancellation. Also there are different types of domes and sizes. Patient comfort plus audibility  is essential. 

I know this sounds technical and not a direct answer but, again there are several factors.  It's best to work with a Doctor of Audiology who has experience and access to more than one manufacturer.   There's so much more to this than just buying a hearing aid. 

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Discussion

Dan S
Dan S 06 July 2017
Don't do it, for several reasons: 1) Leaning on the anti-feedback processing can add as much as 20% to the battery drain, and introduce audible distortion, especially if pole warping (slight frequency shifting) is used. Channel gain lowering is mostly obsolete today, as it can result in a loss of audibility, while inverted phase cancellation is used, sometimes in conjunction with pole warping; 2) You're probably a power junkie from being a long-time wearer (especially if you wore analog aids in the past), and use more gain than is "prescribed" by the fitting formula: Often with my severe-profound patients I switch to Linear (ReSound has this option on the Enzo, and LiNX² when a power receiver is selected) and crank the gain in most channels wide open; 3) All receiver-in-canal aids I dispense have a custom tip included, unless the patient demands a dome: You're paying lots of money for new hearing aids, so demand the best.
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