My dad and a colleague both wear hearing aids and they both complain it’s harder to hear because everything gets turned up. I don’t understand what they mean, wouldn’t it all increase in volume relative to it’s initial volume level?
Side note – my dad just started wearing a hearing aid but my colleague has been wearing one for over 20 yrs so I don’t agree that the reason is not being used to the hearing aid.
In: Technology
Hearing and hearing loss is quite complex. Hearings aids are not capable of restoring all the properties of the healthy cochlea, but the basic volume compensation goes approximately like this:
Our hearing is seperated into frequency bands. You can imagine this with a xylophone, for true eli5. When you lose hearing, your thresholds generally decline in the higher frequency ranges. So you cannot hear the short xylophone parts that well. In the frequency bands where you have hearing loss you need higher volumes to be able to hear it. For example you have to smack harder on the short parts of the xylophone to produce the same volume as a light smack on the long one. Hearing aids follow this frequency band approach and amplify incoming sounds per frequency band, based on your individual auditory thresholds. So, again assuming high frequency hearing loss, it leaves the long xylophone sticks unaltered, but strongly amplifies the short xylophone stick.
In short:
Without hearing aid and gently tapping a xylophone
Ding ding ding ding…….
With hearing aid and gently tapping a xylophone
Ding ding ding ding ding ding
However.
As I mentioned hearing loss is complex and covers far more than just increased thresholds. For example the frequency specificity goes way down in the hearing impaired system. Going back to the xylophone, in the normal hearing system each part activates a single frequency band, but in the impaired system multiple parts of the xylophone might activate the same frequency band in the cochlea. Because of the way loudness perception works, this means that when you have multiple xylophone sticks activating the same band, it appears louder.
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