My journey to a cochlear implant

http://spottedsun.com/my-journey-to-a-cochlear-implant/

by veb • 14 years ago

40 20 14 years ago

gte910h2• 14 years ago

Many people assume these sound much more like hearing aids they do. At best, they sound like a steampunk old time tube radio set with considerable static

http://www.utdallas.edu/~loizou/cimplants/cdemos.htm

for some demos. Ones with few channels sound positively terrifying to me.

michaelbuckbee• 14 years ago

That is fascinating, it makes me wonder if you couldn't use an array of multiple implants to achieve a better level of quality.

objclxt3• 14 years ago

There are a number of issues around quality: the number of electrodes is not always the most important factor. The processing algorithm is also vital to good quality, and that can be improved in situ. There's a lot of research that has gone into algorithms that are best suited to speech, music, etc.

More importantly, many patients receiving implants do not have a healthy cochlear, in the sense many of their auditory nerves may be damaged. In this case the electrodes stimulate the surviving nerves, and additional electrodes may not provide much additional benefit.

Again, the audio quality is really down to the algorithms: because each patient is different the processor can require intensive tuning and individual work to get it sounding reasonably decent. Far more research goes into these audio processing algorithms increasing the number of electrodes (not least because improving the processing benefits both new and existing patients).

DigitalJack• 14 years ago

The problem is stimulating the nerves. While these implants are marvelous, they are still pretty crude in the stimulation portion.

The implant has an electrode array that is shoved into the cochlea. In diagrams of the ear, the cochlea is the thing that looks like a snail shell.

The cochlea itself wraps around the auditory nerve, and normally works with the auditory nerve as a pressure transducer. Pressure changes in the cochlea result in nerve stimulation.

Different frequencies of sound can propagate to different lengths of the cochlea and stimulate the nerves in the respective areas. You can think of the nerve bundle as a piano keyboard wrapped in a spiral. Different frequencies correspond to different positions. So having a bunch of electrodes matters for granularity, but positioning in the cochlea is just as important.

With the implants though, they don't try to stimulate via pressure, they just send electrical impulses through the electrodes. The resulting electric field is what stimulates the nerve.

So it's pretty different from normal functions.

robflynn• 14 years ago

I know a kid who passed out and hit his head and became deaf as a result. He now has a CI. I've talked to him a little bit about it and how it sounds. He described it as "tinny."

I never thought about asking him about static and what not.

objclxt3• 14 years ago

> "Ones with few channels sound positively terrifying to me."

I am told (one of my family members works with cochlear implants) that the ideal candidate for a cochlear implant is a young child who has had severe or total hearing loss. This is for two reasons: if you have never heard sound before then the fidelity is far less of an issue, and children can adapt far easier than most adults.

gte910h2• 14 years ago

But I do see how this could be terrifying to not have sound in your head (a sense you can't easily get away from), then start having this sort of sound in your head.

Derbasti• 14 years ago

Well, you have something like 21 electrodes wound around the hearing nerve. Of those, usually four or so do not work. The rest is all you have available. Simplistically said, you can encode only 17 distinct frequencies.

There are some more intricacies involved, but the general message holds: Frequency resolution is severely impaired. Time resolution and loudness levels are diminished, too. In fact, many CI patients can not percieve music any more.

Funny enough though, they can usually enjoy music they knew from "before".

Still, it is a wonder of modern medicine to give hearing to people with nothing more than a working hearing nerve. CIs are true nerve-computer interfaces.

jakozaur• 14 years ago

Startup request: create a service where you could transcript just from videos, without voice. Ideally a mobile app.

Some of the use cases are somewhat creepy, but there are quite a few legitimate ones. In particular, there are a lot of recording where sounds is broken/terrible and you could "restore" does.

You could start it yourself, but later you could make some kind of marketplace.

malkia• 14 years ago

That's probably very hard, and then you have the "Bad Lip Reading" channel on youtube :)

williamjackson• 14 years ago

My wife received a cochlear implant in October, so we are on this journey right now. It has definitely been frustrating, but we have seen progress and we are optimistic about the future. If you are interested you can read about the implant activation process here:

http://hegavememyears.blogspot.com/2012/10/what-i-saw-at-act...

outworlder• 14 years ago

> "From their studies, they found that there were four generations of my family with the A7445G mutation and the pattern showed that it is a maternal mutation, i.e. it is carried out by the females of the family and passed from one generation to the next."

Isn't that always the case with mitochondria, since they only come from the mother?

I am not a geneticist, so this is a real question.

Adrock• 14 years ago

Yes. In the comments, the author mentioned that they know this is redundant, but only if you already know it is.

leonpanjtar• 14 years ago

My friend has a daughter who was born deaf and then she and her husband decided to implant her. It was a really hard decision but she was 4 and still not walking due to balance problems and because she didn't hear her surroundings. Well the decision payed off. She is 5 right now and she is walking and running and she started talking a few baby words, so the doctors are pretty sure she will be talking soon. I have been around in her life for about 4 years and I must say that since she got the implant she became a much much happier child.

ocean12• 14 years ago

I really get a kick out of these personal stories that pop up on HN. I'd never find them otherwise.

pjin• 14 years ago

There's a really cool experimental history behind understanding the cochlea, especially concerning George Zweig, once a particle physicist. A lot of this work was done in the 70s and is, IMHO, some of the best examples of biophysics you can find.

One of the relevant papers you can find on google is: http://symposium.cshlp.org/content/40/619.full.pdf

joeyo2• 14 years ago

> The disbelief came when it was time to listen to singular > words. With the screen turned off, I got 0%. With the > screen turned on, I got 8%. That’s crazy!

It's really amazing how pervasive (putatively Bayesian) multisensory integration of information is in the brain. Even individuals without impaired hearing have their auditory perceptions strongly a affected by other inputs. The McGurk effect is a great example of this:

http://en.wikipedia.org/wiki/McGurk_effect http://www.youtube.com/watch?v=G-lN8vWm3m0

My journey to a cochlear implant

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