How do hearing aids work? Are they just blasting what they hear directly into the ear potentially causing more damage?
In: Biology
Hearing aids aren’t just amplifiers – they filter and normalize frequencies to adjust to the weaknesses of the wearer’s ears. They are tuned for individuals by professional fitters. To answer your follow-up question, hearing aids can actually protect against loud sounds since they can block and selectively filter.
Person who has hearing aids here. In terms of damage there is one thing that bothers me the most because nobody told me that even though It makes sense. Your hearing without them gets worse and worse which is the thing that hit me the most. I think It’s because your ears are happy that they don’t have to work hard and because of the extra help they don’t need to make their job. (That’s at least how I got told the reason)
Edit: reason is NOT true at all and was just too simplified.
I’ve been informed (by people who have researched hearing aids quite a bit) is that the belief is that getting hearing aids can actually slow down the deterioration of hearing. I’m not sure what the mechanism for that is supposed to be, though.
The new, high end hearing aids are pretty nifty (and expensive). They include equalizers so that only the bands which need amplification are boosted. Various different settings can be used for different environments. They can be Bluetooth enabled so that phone calls can go straight to your hearing aids. They supposedly can reduce tinnitus, too.
There are different types of hearing aid, because different parts of the ear could be damaged or defective.
If you look at [the diagram](https://www.bksv.com/-/media/Images/Waves/2018/01_Anatomy-of-the-human-ear/Anatomy-of-the-human-ear_01.ashx?h=552&w=875&la=en&hash=CA79680318C10B80E2A4343E8BEA13934C861455), the eardrum vibrates with the sounds in air, but that vibration is transmitted via bones to the cochlea, which is a chamber filled with liquid and soft hairs that are attached to nerves.
So if every piece of the ear anatomy is “ok”, then the hearing aid can just amplify the sounds so they vibrate the eardrum a bit harder.
Otherwise, an implanted type of hearing aid could pick up the sounds via a microphone, and apply the vibration directly to the bones (if the eardrum is ruptured). Or, with a [cochlear implant](https://cdn.prod-carehubs.net/n1/802899ec472ea3d8/uploads/2016/10/a-medical-illustration-of-a-cochlear-implant-original.jpg), the sounds picked up by the electronics are applied directly into the liquid environment inside the cochlea, bypassing the eardrum and the bones completely.
Am hearing aid user.
Good hearing aids amplify high, low, and in-between sounds exactly as much as they need to make a person’s hearing normal. I have hearing loss that effects high sounds, so my hearing aids pump up mostly high pitched sounds that mix with real sound.
Most hearing aids max out at certain volumes. Mine stop at 107 decibels, which is around when sound can hurt someone’s hearing. If someone needs sound to be louder than that to correct their hearing, they need to get something other than hearing aids (cochlear implant). If real sound is louder than 107 decibels, my hearing aids do nothing. If real sound is 106 decibels, but my hearing aids are supposed to add 10, they only add 1, because they won’t go over 107.
This is good, because only one part of my hearing is broken. There are four steps to hearing: the ear drum, the ear bones, the hearing nerves, and the listening brain. My damage is in the hearing nerves. If sound is too loud, I can still damage my ear bones, and I have. I used to think “I’m broken, so I don’t need earplugs!” and didn’t wear them when I should have, and hurt my ear bones, which made my hearing worse.
Have you ever seen a professional musician mixing board, with all the levers and nobs? A good hearing aid has those same nobs, but all computerized. A good hearing aid doctor is called an audiologist, and will tune a hearing aid to be perfect for someone’s hearing damage.
There aren’t that many laws in the United States about hearing aids, so you don’t have to be an audiologist to sell them, and you can sell bad hearing aids. There are places where non-doctors sell hearing aids that just blast everything really loudly. They are not good, but they are also cheap. I would not recommend then.
There are different kinds of hearing aids. The specific type depends on the damage to the ear.
If you just “hear bad” specialized amplifiers can be used to alter the volume and frequency range to improve your hearing.
If some parts of the ear are damaged a cochlear implant can be used. This is basically a microphone with some electronics that is direct hooked up to the nerves in the inner ear and stimulates them to allow hearing.
Old ones did just amplify everything regardless or frequency or decibels so that far off siren is just as loud as your gf telling you to get off the couch. New ones are really nuanced and high tech so they can tell what to filter and what no to.
The tech now is pretty amazing. My husband has a set from the VA as a treatment for his tinnitus. He was in aviation fuels on an aircraft carrier during his service. They are specifically tuned to add white noise to cancel out what he hears as alternatively buzzing/ringing. Amazing. He can also answer his phone, stream music, watch movies, etc.
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They do increase the volume of what they hear, but only up to a safe limit, so they don’t damage the ear. These limits are set by the fitter based on a hearing test.
There’s lots of other processing that they do to avoid blasting everything, and only what the hearer wants to hear. There is a LOT of research that goes into how exactly to do this.
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