I will try to answer your questions.
Q) Howcome when I search the internet, it gives different values for converting? For example it gives a value of 7db SPL at 1000Hz. None of the values are below 7db SPL from what someone tested the audiometer with a db SPL meter. For example at 1000Hz hearing at 77db SPL puts your loss at 70db HL.
A) I gave you values that you cannot easily search on and based upon 1/3 Octave Bands. Not everything is published on the internet. In addition, each company may have slightly different fitting algorithms and candidacy selection methods. The most common (but not the only one) is DSL.
Q) How am I seeing a percentage of people that were able to preserve some or even all of their hearing? Did they get special electrodes placed in the right positions that don't interfer with the hair cells? Some of those people got full electrodes, not the shortened ones used in hybrid CI/HA clinical trials.
A) I hate to say this, but some people respond to surgery better. There are better surgeons. Everyone’s anatomy is different. If everything is optimum, there are better results. Surgery is an art not a science. Also, a very well inserted electrode with hug the inner wall but that is not always the case.
Q) What happened to that 128 electrode CI being developed since 2006?
A) I looked at you link. It is a university project. It doesn’t appear that long term biocompatibility is an issue with that design. Also, that is just an electrode. The electrode must still have connections into the inner electronics via feed-throughs. I have heard rumors that the worlds largest medical company (which doesn’t make hearing implants) is developing a 30 pin feed-through. You must remember that you have to make a CI electrode conductors of a very stable metal for long term use. The metal must also be biocompatible. Currently, platinum is the metal used. The metals are then encased in a biocompatible silicone to make the electrode. Yields are very low and materials are very expensive (during the past year platinum has sold for between about $1000 and ounce and $2000 an ounce).
Q) Google laser or fiber optic cochlear implant. Plenty of articles that discuss this new technology. Maybe it's being developed in secret but could be several years away.
A) Here is a good link.
Technology Review: Making Deaf Ears Hear with Light
Reading this is just experimentation and theory. Here is what they say:
“A major question is whether it's safe to stimulate nerves in this way for long periods of time. So far, Richter and his colleagues have shown that auditory nerves in anesthetized gerbils can be stimulated with infrared laser radiation for up to six hours without damage. At present it's not feasible to run the tests for longer, but Richter is planning long-term studies in animals with permanently implanted devices.
The researchers are also figuring out how to precisely control neuron activity with lasers. The ear encodes pitch and loudness not just by firing nerves in particular places, but also by modifying the rate at which they fire. So far, Richter has shown that laser radiation can reliably make neurons fire up to 250 times per second, which is comparable to the rate at which early-model conventional cochlear implants drive neurons. “
While they may be possible in the future, they are not main stream and not being actively pursued (to my knowledge) by any of the commercial ventures. Once they begin clinical expect at least 3 years from when they will be approved in the USA (best case).
Q) How much would this cut down on the cost? Current CI costs $50,000 but those getting CI usually pay much less or nothing at all due to insurance. So really it's the insurance companies that will benefit from the savings.
A) $50K is the cost for everything. The CI is likely $20k-$25K of that price. Keep in mind that medical devices are not fixed price commodities. A doctor who buys more of them gets discounts (and he makes a profit on selling them). The same is true for HA. This is the same reason why Best Buy sells cheaper. They get volume discounts.
I would suspect that when a company reduces costs of manufacturing the patient will not see a drop in price. Much of the price of medical devices is insurance for the company, manufacturing costs, research and development pay-back, etc. Taking a quick look at Cochlear Corps 2008 Annual report they were running at about 19% profit levels. If they can take the cost of manufacturing down, they will make a little more money.
Q) Ive been wondering why some of us still benefit from HAs despite being profoundly deaf(90-110+ db losses) As for dynamic ranges, doesn't CI also have a small dynamic range? Im still wondering if the gain/SPL manufactors list on their HA specs are A or C weighed? In another thread, I said:
A) I am not talking about the dynamic range of the device. It is dynamic range of the patient. If you have 30dB dynamic range (90db to 120db) then “normal” sounds which go from 0-120db must be compressed into your dynamic range of 30db requiring a 4:1 compression. Keep in mind this is very simple and high end devices this is frequency dependant and can also have knee points. This means that low volumes are amplified more and high volumes are compressed more than 4:1.
Q) 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.
A) The short answer to this is sounds are not perceived equally across the frequency range. A HA can be fitted to sound very loud by increasing gains in the 250-750 range. However, they hearing aid may sound loud, but it helps very little on speech recognition. Speech recognition is from around 1k to 4K. And the 1K to 3K is most important.
Perceived loudness is one of the issues that conventional HA have issues with and the implants seem to be winning by large margins.
I am sorry to be vague on some things. However, I can only give what is considered “general knowledge”.
Seriously...but is anyone going to get that high? Probably not. If I'm not mistaken, Cochlear has the largest DR compared to the rest of the companies, but it's just available, it doesn't mean a larger DR makes it better. I have a DR of 42 in my left and DR of 34 in my right. I probably will need to increase the DR a little in my left. It just gives you a range between the softest sound to the threshold. If I have it much higher (let say in the 60's for example), it will be way too overwhelming for me. Hence, this is why MAPping is involved to tweak even further on individual electrodes.
