Another Mapping

It looks a bit different today.

Laynie had her three-month mapping today. She was disappointed to test at 35-45 dB for 125 Hz to 4000 Hz, because she was hoping for 25-30 dB across the board. She was still at 25 dB at 6000 Hz and 20 dB at 8000 Hz. High frequencies certainly are her strength these days.

Steve, Laynie's audiologist, redid her map from scratch, which was a great idea, in my opinion.. exactly what I was hoping he would do. I guess you need some context to understand what that means.

When Laynie's implant was activated, on February 13, she got her first map. A map is basically a computer program on the cochlear implant, and it controls how the implant processes sound and the way it stimulates her nerve fibers. The Med-El Sonata implant, which is what's in Laynie, has 12 electrodes. At the first mapping, Steve programmed each electrode by asking Laynie to tell him when the sound (beeping) was comfortably loud. At the second mapping, he took that same map and just made it louder. At the third mapping (and the third mapping was only a week after the first one), I think he increased the loudness and had her listen to electrode one and compare the loudness with electrode three, etc., trying to even them out a little. He didn't start over, just refined what she already had. At the fourth mapping, which was two weeks after the third, he kept the same map and made it louder. At the fifth mapping, Laynie told Steve how much high-pitched sounds were bothering her, and he decreased the stimulation on some of the electrodes and increased it a bit on other electrodes. I mean, more goes on at these appointments, like checking nerve responses, but as far as changes in the maps, that's it.

I don't think Laynie had enough "sound knowledge," if that makes sense, to give him decent feedback on what she was hearing. He did not test what she was hearing until the fourth mapping, and the only testing he has done it pure tone (sound field) audiometry. No speech recognition, CNC words, spondes, or sentences. Laynie would do poorly on those tests, which is probably why he has not done them. Although, I do think there is value in having low scores, because you can measure progress from them.

So at this latest mapping, Steve cleared the programs on Laynie's speech processor and had her listen to the beeps and tell him how loud they were on a scale of 1-10. 1 is barely hearing, 4 is medium soft, 6 is most comfortable (the target for conversational speech), 8 is barely tolerable, and 10 is painfully loud. So Laynie told him where to stop for each one, and then they compared electrodes to try to get the volume as consistently as possible across frequencies. Oh, and Steve was showing waaaaaaay more signing skills than he ever has. He can have a basic ASL (okay, PSE) conversation! He tries to front, but we're on to him. Laynie has been saying for a while that he seems to understand her sometimes, because he will be ready to answer before I have finished interpreting.

Anyway, that's a bit tangential. One odd thing happened at this mapping: when Steve stimulated electrode 10, it caused Laynie pain. That has not happened before. He turned off that electrode.  ?  Hopefully there's nothing seriously wrong.

The map that Laynie ended up with looked differently than the previous maps. It's kind of hard to explain.. would be much easier to draw! OK, the computer program shows the stimulation levels of the 12 electrodes as sort of a bar graph, with electrode number across the bottom and amperage (?) vertically. A higher bar equates to increased electrical stimulation. Laynie's bars used to look pretty much straight across, with a slight upward curve at the end. Now, they look the opposite! Electrode 1 is now the strongest, and electrode 12 is the weakest. But she felt like they were equally loud. I guess she does not need as much stimulation to pick up the higher frequency sounds of electrode 12. Now, it wasn't consistently decreasing with each electrode, but that was the general trend.

The reason I wanted Laynie to have a completely new map (rather than simply adjusting her previous map) was that she was having trouble discriminating speech sounds within a class, such as /m/ vs. /n/ or /l/ vs. /r/, with the exception of fricatives (s, z, sh, f, v, th). Fricatives are distinguishable based on high frequency information (i.e. over 4000 Hz), and she did well discriminating words like "sun" and "fun" or "thick" and "sick." Laynie was also struggling to discriminate low-mid frequency speech sounds of different classes, such as /m/ vs. /r/ or /b/ vs. /w/. Hopefully she'll have more luck with her new, more balanced (fingers crossed) map.

I guess that was pretty much it. He wished her luck on her second surgery. Normally she would be back to see him in three months for the next mapping (her six-month mapping), but her right implant will be activated before that. We will make the activation mapping appointments through the surgeon's office. Her right implant surgery date is July 13, barring any insurance snafus. So that implant should be activated in the middle of August.