Time to Read: 6 minutes
This question and answer is from the February Ear Talk webinar with Value Hearing founder Christo Fourie. You can find the full presentation on YouTube. If you would like to have your question answered live, leave a comment below RSVP to the next webinar which is on the third Wednesday of the month at 11am AEST.
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The spec sheet for my hearing aids, GN ReSound Linx Quattro 9, shows they have an impressive list of fancy technical features to improve hearing, including 17 channels. How does an audiologist adjust all these different capabilities to give the combination which best addresses my particular hearing problems? Especially how these capabilities are matched to the problems revealed by my audiogram.
Okay, this question was one I got quite excited about, simply because it's something we audiologists take for granted. But seeing this question makes perfect sense, so thank you very much for submitting this one.
Essentially the question is, you've got all these features that's listed for any particular hearing aid, in this case it's a ReSound hearing aid. And the question is, ‘how does the clinician set that up to work specifically for the client’, which is a very very valid question.
From a clinical perspective, however, you've got to consider where we're coming from as audiologists. Our first role is to give you optimal amplification of speech and that is what we're always going to focus on.
When we look at the hearing aids, the fitting software from our perspective is actually laid out in the order of importance.
The first screen (pictured at right) we see is gain adjustments and that is all about matching the hearing loss of the client to the hearing aids output and there we've got to keep things comfortable, we've got to keep it safe so we don't boost things so we cause damage, and we've got to make sure that all speech sounds are audible which we do through real ear measurements.
Initially we want to make sure you can hear the soft sounds, the medium sounds, and the loud sounds without being too loud. Yes, the manufacturer then does give you all these features to play with, but if you think that the brain is really the organ that does all the hearing, your normal ear doesn't have any of these features so a lot of these features might relate to comfort, some of it might relate to how the brain processes speech, and a lot of it's designed for edge cases.
What the manufacturer actually does is set defaults for particular audiograms which are shown to work the best, because there's no way in an hour-long fitting session we can experiment with each little default in a controlled environment and expect that to have a certain result in real life.
So typically the hearing aids are set at specific defaults based on your audiogram by the manufacturer. After we've set up these gain curves correctly, we then use the follow-up appointments, which is why it's so important to go back to your audiologist not only once you first got the hearing aids but also regularly, about every six months, to make sure things are working well.
The feedback you provide the audiologist means they can then go into these specific features and start adjusting them according to your needs.
There are a few features we check when we fit things, like making a loud sound - clapping a hand, shaking a container with some coins in it, banging plates etc - just to make sure the hearing aids are comfortable.
We could also look at things like, does the client complain about tinnitus? Is the hearing aid gain sufficient to address the tinnitus? Or do we need to turn on a tinnitus masker? Is the client often out on sailing yachts? In which case we might add a different program with wind guard because the caveat with all these features is it changes the way the hearing aid processes sound.
If you put in too much noise reduction, and the hearing aids have specific channels, what the noise reduction will do is pull those channels down. But those channels might also contain speech, and if you pull it down too far the speech suffers. So you can actually cause issues by just turning everything in full, which is certainly why most of these are either off or set to mild as default.
It's really a fine-tuning opportunity for your clinician and the more features the hearing aid has, the more the clinician is able to fine-tune it for your specific needs as you report your experiences in different situations.
That also comes into things like this screen (at right) which is the third most important and that's how the hearing aid would react and what it would do with its volume in different situations.
This is more how the hearing aid functions automatically, so if someone complains about noise, we can adjust it so it pulls down the volume a bit more or give you a bit more speech clarity. But again it is a fine tuning option rather than something we do at the fitting.
At the fitting you're not necessarily going to have the experience and the environment to be able to judge these changes so that's why the follow-up period is so important.