Noise is inherently low frequency. If you have reverse slope loss and your hearing aid is programmed with too much low frequencies, that would interfere with your clarity for speech understanding, especially in noisy situation. I would try to increase the mid frequencies and lower the low frequencies, as you probably would have enough high frequencies already. A discrimination test with the hearing aids in the ears would probably help to determine the effectiveness of the hearing aids after they had been programmed.
Refer your audiologist to The Bizarre World of Extreme Reverse-Slope Hearing Loss.
I read a research article about programming hearing aids for reverse slope audiograms. I don't remember the title because it was a few years ago, but it talked about how you program the hearing aids for more gain in the high frequencies and less in the low frequencies than you would expect from just looking at the audiogram. I don't know if this has been tried yet. A reverse slope can be a hard hearing loss to fit.
1) Your audiologist must rule out Auditory Neuropathy Spectrum Disorder (ANSD), and low frequency cochlear dead zones, which is a form of ANSD. The screening test is measuring the acoustic reflex thresholds across the speech range, and if they are above 90dB or missing, dead zones/ANSD is in play. The Threshold Equivalent Noise (TEN) test is available from Prof Brian CJ Moore at Cambridge; or from Frye at a slightly higher price (they also have a better explanation of it on their web page). You can read more here;
2) Refer your audiologist to the Reverse Slope Hearing Loss group on Facebook, where she can read the pinned post and the comment thread, which includes curated comments on pertinent subjects as cochlear dead zones and upward spread of masking;
3) Although both Neil Bauman & I have been doing it manually for years, instruct your audiologist to use Oticon's VAC+ fitting formula, which is the "least worst" of any of the formulas.
Reverse slope hearing loss is impossible to fit without performing real ear verification testing. The generic fitting algorithms in most manufacturers software is based off an average and not typically the best for reverse slope hearing loss. Make sure your audiologist is following best practices and performing real ear verification testing while the hearing aids are in your ear.
Reverse slope hearing losses are difficult to program for, and keeping realistic expectations is important.
A couple of questions - Do you have custom earmolds or do you have earbuds? Custom earmolds can help emphasize the low tones and achieve better control over noise. This might be something to try.
Have you been doing any auditory rehabilitation along with wearing hearing aids? Brain training excercises can help us maximize the hearing we have. If you are not doing auditory rehabilitation, I highly recommend trying it. Ask your Audiologist about how auditory rehab can help you improve your speech understanding in noise.
Is there another audiologist in the clinic who can help? Sometimes getting a second opinion can help. That is not to say your first audiologist is not good, however sometimes a second specialist can see something that the first person didn't think of that may help. There are also audiologists on demand for most manufacturers, and perhaps it would be worth asking about getting expert assistance from the manufacturer.
Do you have auditory deprivation? Was your hearing loss left untreated for many years before you got treatment? Unfortunately, when a hearing loss is left untreated for a very long time, sometimes there is only so much we can get back even with the very best hearing aids and very best programming done on those aids. Having realistic expectations is very important when treating hearing loss. While the technology available today is the best it has ever been, we still cannot get back the lost speech understanding that is caused by deterioration in our brains from leaving hearing loss untreated for many years. This is why it is so important to get help for our hearing early, as soon as we first notice symptoms of hearing loss creeping up in our lives rather than waiting until the problem is "bad enough" to do something about it. Like all health conditions, early detection and treatment produces the best outcomes over the longest period of time. If auditory deprivation is present, auditory rehabilitation is even more important.
I hope this helps!
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