Decisions, decisions

Leading up to the decision to have a cochlear implant (CI) installed, I did quite a lot of research using the web, various newsgroups and some books. Many recipients have created their own blogs or web pages describing their personal stories. For example, I found this one especially useful as it has lots of pointers to other blogs and resources:
Chronicles of a Bionic Woman

One concern was that this was new, untried technology. I was surprised to find that CI’s have been around for about 30 years. In that time, some 150,000 people have been implanted worldwide. The device failure rate for the internal device is low and continues to fall. So I will hardly be a guinea-pig.

Speaking of guinea pigs, a second concern was that I would potentially lose any residual hearing in the implanted ear. This would mean that I would be no be able to take advantage of any future medical advances such as gene therapy. Reading up on this, it was apparent that such breakthroughs, while promising, are a long way off and to date are only at the guinea pig or lab-rat stage. It seems improbable that this technology will become available in my lifetime. Also, the cause of my hearing loss is unknown and it’s likely that this type of intervention would only be useful for very specific types of hearing losses with a well-understood genetic basis.

I was also concerned about obsolescence. The life-cycle for hearing aids is assumed to be about five years; in fact, manufacturers will not repair aids that are more than ten years old because parts can not longer be obtained. A hearing aid can easily be replaced with a newer model but this would not be an option for a device embedded in my skull. I was reassured to find that most of the development is happening with the external processors and, especially, with the software ‘maps’ that the processor uses to translate sounds into electrical signals for the implant. Many of the early implantees are still using their original implants but with upgraded external hardware or software. If I were to get 30 years of use out of an implant, I will be well into my 80’s. That would be pretty good run!

And I was mystified about the actual surgery process. The cochlea is very small: about the size of a pea. Within that space there are three separate channels or cavities all coiled up together. If it were uncoiled, it would be about 4cm long. How was a surgeon going to feed 24 electrodes into that one of those channels? I’m still not entirely sure how this will work but I was somewhat reassured after watching this video of the operation:
Cochlear surgery
(don’t watch this during dinner!)