OT: hearing loss? cochlear implant--a story

Isn't modern technology amazing! Glad to hear about it. Lane

Another interesting prosthetic device that is under development uses electrodes on the tongue to provide 'vision' to blind people.

Leon

Way Cool! My bud is an audiologist and checks my hearing every year over a beer and I have seen age and machines take their toll, my high-end is shot. I pity these kids with the 500 watt stereos in their cars; what a precious gift they are squandering.

Reminds me of one day I was stuck in some stop and go traffic on I-5 on a warm summer day. The lane next to me was moving slightly faster than my lane. I started to hear the boom boom of someone's loud stereo, the closer it got the louder it got. Eventually it was even with my car, the noise was literally deafening. I looked over to see what kind of creature could withstand such an onslaught. It was a guy in his late teens early twenties of course, but he had bright green ear plugs in. I laughed out loud, but of course he couldn't hear me. What was he thinking?

Lane

That it's better to give than to receive?

Some folks don't enjoy music: They inflict it.

I frequently wear earplugs when going into loud enviroments. Parties too...

A yellow foam earplug cut in half (lengthways) is very discrete, and allows you to actually hear better.

You feel the bass in your body, and can hear the music/conversations too better as your ears are not overloaded.

I have occasionally done this at home: turn audio system way up, insert earplugs, and do noisy task while able to hear audio.

Give your Dad my congratulations. It sounds like he's a star patient.

Since I worked in hearing research for 15 years or so, if you don't mind, I'll give you a little better description of the CI.

Electrodes are an array of 22 in your Dad's case, arranged in a string, almost literally. The string of electrodes are, in its natural state is curled like the spiral of the cochlea. They may use a form of memory metal or something else now, but the array starts out straight and as it's inserted into the cochlea it starts to curl to bring it into close contact with the cochlear wall possibly the basilar membrane. There are many more nerve cells than there are electrodes and the electrodes are much much larger than the nerve cells. The critical thing from what I remember, is that the electrodes need to be in very close contact with the tissue in order for the electrodes to function. There are often a number of electrodes that don't function in every implant.

Signal processing is fairly complex and the manufacturers consider this proprietary information. From what I have seen it seems to be a variable band pass filter is associated with each electrode as you would expect. I also think there is a variable DC component involved and obviously a lot of other things that I never knew about.

The external piece is usually magnetically mounted to the implant device. The implant is powered and the processed audio communication is done inductively probably at radio frequencies.

Cochlear implants don't provide hearing as you and I know it. It's really a neural signal that people can usually learn to use like hearing. It is amazing how fast some people adapt to it. Others find it initially disorientling. One story I heard was a guy who said his first sensation from his CI was in his foot. As his brain adjusted to the neural input it moved up through his body until it was more like hearing. CI usually works best on adults who where previously hearing. The group I worked with mostly worked with children who were born deaf. Keep in mind that I only had peripheral contact with this part of the clinic.

Hope this helps, my best to your Dad.

Cheers,

Kelley

Another great Australian Invention