You know what I don't get, why you think that 120 db is untouchable with hearing aids, but 110, and 105 (which you have) is extremely aidable and should never get a CI.....:roll:
I was wondering the same thing to be honest. I will have to ask my audiologist(s) this. Those reading my post can offer their own theories as well. Let me share my experience what it's like. The results are with the speaker volume cranked up.
250Hz(75db HL) and 500Hz(90db HL): I hear low frequencies up to 500Hz very loud. I can still hear those from the other side of the house!
750Hz(105db HL): I still hear this tone very loud but notice it's half as loud as the 500Hz tone. I can hear this tone from the other room!
1000Hz(110db HL): Much softer than 750Hz, about half as loud and about a quarter as loud as 500Hz. I can still hear 1000Hz from the other end of my room!
1250Hz(115db HL): Less than half as loud as 1000Hz, this tone is quite hard to hear even if I put my ear to the speaker. I can't hear it from more than about 3 feet away.
1500Hz and 2000Hz+(115db-120db+ HL): Most of the time, 1500Hz is inaudible. On a good day, I hear it from a few inches away at threshold levels.
I am personally surprised by that disparity, once I reach 110db HL, each few db above that quickly fades into nothing. But I hear sounds very loud and well at levels below 110db HL, even the 750Hz tone I can hear very well! I have a piano when when I play it, there is a small difference in loudness between the low(first set) and mid frequency keys(second set). It's when I get to the high frequency keys(third set) that I can tell a noticable volume decrease between each key. My parents do not experience this however for any keys. My dad only experiences this for the last few highest keys since he has a moderate high frequency loss. But for me, the last dozen keys are silent, and the keys before that are very faint.
Some possibilities and theories:
1. Perhaps the dynamics of the ear changes at 110db and up. Below 110db HL, there still is enough functioning hair cells that can be stimulated/amplified. Once you get to 110db and up, there is so few, if any hair cells. Ive read into cochlear dead regions where a very loud sound actually stimulates adjacant hair cells and this does give the person a perception of hearing. The sound may be noiselike, very distorted, off-frequency, felt as a woosh, or simply very faint.
2. I wonder if it's a limitation of HAs but after trying my old HAs from 1998 and comparing my new HAs from 2008 with neither giving me hearing above 1250Hz, but the new HAs making sounds at 1250Hz and below 2-4x louder, yet still not being able to give me anything usable at 1500Hz, I suspect it's my ears.
3. I am able to get a response on the audiometer at 1500Hz, 2000Hz and sometimes even 3000Hz in the 115db to 120db range. But I don't recall hearing any shrill tones or whistles. It's likley I heard a low frequency distortion that came from the audiometer and/or due to the cochlear dead region phenomenon. I also hear the same distortion comming from my speakers at 1500Hz, 2000Hz, 3000Hz, 4000Hz, etc. It sounds like "ehhhh" like humming or static.
4. I will find out more when I ask my audie about this and when he reprograms my HAs. He did say that at 120db, HAs cease to become useful. I can ask him what about at 110db, 115db and in between 110db and 120db.
5. I do know that the pain threshold as well as UCL(uncomfortable level) occurs at or around 120db. Thus even if you could attempt to amplify a 120db loss with an insane amount of gain/SPL, it won't be pratical as there's zero dynamic range, would not be comfortable and might even cause damage to adjacant functioning hair cells.
