Thursday, November 27, 2008

How do you get a CI, anyway?

Well, first you have to be deaf. The FDA guidelines currently require that you have severe-to-profound bilateral sensorineural deafness, that you do not receive benefit from hearing aids, and that you're at least a year old. Well, phooey on them. The FDA guidelines are just that -- guidelines, and not legally binding.

Ben does indeed have severe-to-profound bilateral sensorineural deafness. The hearing loss classifications (mild, moderate, severe, profound) are determined by hearing thresholds, as given in decibels (dB). (Actually, they are given in dB HL, i.e. hearing loss decibels. Nobody has been able to give me a straight answer as to exactly what these are, and how they are related to the regular decibel system, which essentially tells you how loud a sound is. Specifically, the number of decibels is the logarithm of the power of the sound. But I digress.) For example, if you hear nothing below 90 dB, then you are profoundly deaf. This is all complicated by the fact that almost nobody has the same degree of loss over the entire frequency range. Typically, a person has better hearing at low frequencies than high ones. In his left (better) ear, Ben hears "low" frequencies (low for the purposes of speech perception, namely 500 Hz) at around 65 dB. Higher frequencies he doesn't hear until around 80-90 dB. So the hearing loss in his left ear is severe-to-profound. The loss in his right ear is profound.

The "sensorineural" part means that the hearing loss is due to problems in the inner ear, auditory nerve, or higher levels of auditory processing, as opposed to an obstruction or abnormality in the outer or middle ear. In Ben's case, the culprit is the hair cells in the cochlea.

Some people have a "reverse slope" hearing loss, meaning that they hear better at high frequencies. (Leah, if you're reading this, I'm thinking of Nolan here.)

The FDA used to require a profound hearing loss for CI candidacy. Then it was discovered that profoundly deaf people with CIs performed better than severely deaf people without them, and it seemed a bit unfair to deny the latter group the benefits of a CI. In fact, I think that people with CIs often perform better than people with moderate hearing losses; however, at that point, the benefits may not be substantial enough to warrant the costs and risks of surgery.

You need to undergo a trial period with hearing aids in order to demonstrate that you do not receive (sufficient) benefit from them. Ben was first fitted with aids back in January of 2008. After a couple of months, we were increasingly confident that he was getting some meaningful sound in his left ear, but it seemed like there wasn't much going on in the right. This was verified by a number of hearing tests in Buffalo and at the NYU Cochlear Implant Center, where we went for candidacy evaluation in June. We took advantage of the hearing in his left ear to pump as much sound and language into him as we could, and I think this early exposure has been very beneficial to him. But it was pretty clear that the amount and quality of sound that he was getting with the aids was insufficient for spoken language development over the long haul.

Another thing you need before CI surgery is a CT scan or MRI, to look for structural abnormalities that might complicate the surgery or render the implant ineffective. Ben had a CT scan in May.

Now, Ben was implanted at 8.5 months. Increasingly, CI surgeons are implanting before 12 months. Some implant centers still refuse to do this. One of the reasons that we travelled to New York City is that the NYU Center has done many implantations at less than 12 months. We are absolutely convinced that Ben's rapid and easy progress with hearing and language with the CI is largely due to his early implantation, and the extra four months of hearing this bought him at a crucial period of development.

Our insurance company was not so enthusiastic, though. After initially telling us over the phone that they had no minimum age requirement for CI surgery, they then refused to approve the procedure, on the basis that implantation before 12 months is still considered "experimental." We found this out a few days before we were supposed to head back to NYU for the surgery. Maybe I'll give the full story of our insurance battle in a future post, but the short version is that we launched an expedited appeal, our surgeon intervened on our behalf, and eventually we were approved. Our surgery date had to be pushed back a little over a week, but that and a boatload of stress were the only costs to us.

So Ben went in for CI surgery on Friday, July 11. The operation went beautifully and quickly. We spent one night in the hospital, and he was discharged around noon the next day. He recovered very quickly. The device was not activated until July 31, because the incision site needs to heal completely. I'll give a full account of activation another time. This post is already quite long enough!


leahlefler said...

Julia, would you mind if I linked your blog to mine?

The reverse slope loss is interesting- we've gone from reverse to almost flat to peaked to reverse again (darn fluctuating losses)! Nolan used to hit normal in the high frequencies and was moderate in the lows. Now he's moderately severe in the lows and mild/moderate in the highs. Sometimes I feel like the sound booth is a random number generator.

His hearing aids definitely help him. The only problem is in noisy environments, when he behaves as if functionally deaf. I think CI's have the same "hearing in noise" issues, though.

I also think one of the contraindications for cochlear implantation in moderate kids is the potential for destruction of residual hearing. I've heard the electrode arrays are gentler now and they can often preserve residual hearing, though. It will be interesting to see what the future brings!

Julia said...

Please do link us up! And I should put a link to yours on mine. I wonder how I do that? :)

Ah, booth tests. Michelle "boothed" Ben the Thursday before Thanksgiving, and with his CI he responded to speech at 15 dB and pure tones in the 15-20 dB range. The following Monday we were back in the booth at NYU, and the audi there couldn't get any pure tone response out of him until about 35 dB. I was on her side of the window so I could watch Ben, and both Neil and I are convinced that he was hearing those quieter tones, but too busy playing with toys to look up. There's definitely a random element to the process.

I think they're better at preserving residual hearing these days, but there's still a good chance of losing it. A mother on cicircle recently said that one of her daughter's ossicles had to be removed during the surgery, so that means that all residual is now gone in that ear.

leahlefler said...

OK- I've linked your blog (I created an item list a long time ago and now can't remember how I did it, lol).

Losing residual hearing would be bad for us. Nolan's worst hearing is at 60dB in the low tones, and his best is at 2000Hz (35dB). That 35dB unaided level means he can hear us and responds rather well without aids- in fact sometimes it can be hard to believe he has a hearing loss at all. Other times (in noise or if we speak softly), it becomes more apparent.