Brain stretch

12 07 2011

I’ve had my shoulders around my ears for most of the past year and so I went back to the hospital to see what they could do.  I was finding some noises were still quite loud and uncomfortable – such as rustling paper, people coughing, doors slamming, aeroplanes, people zipping up bags, crockery being put away in the room next door was just too sharp …. and I didn’t have a lot of clarity with speech either. I  wanted to ask my audiologist to turn down the volume, as my nerves were just shredded and I didn’t want to put up with much more of this. I was just fed up with the overstimulation. Is this normal? Is this what the world is supposed to be like? So noisy and ‘soundy’? I’d given myself 15 months to settle in and get used to the barrage of sounds, but on some days it felt overwhelming. Just too much. I didn’t know what was normal. What I should get used to. What is too loud and what isn’t. I felt as if I was drowning in a sea of sound. Whatevs….. I’d had enough.

When I undergo a mapping, I am able to indicate to the audiologist when I have reached a level of sound that feels comfortable to me, but above that, everything sounds the same. So the audiologist had been setting the levels higher and higher over the last year as I seemed fine with them. I just couldn’t tell the difference between loud and louder. I don’t really have any knowledge of sound and therefore I’m not very good at giving my audiologist information on my threshold and comfort levels. My brain was totally confused.

My audiologist decided to try something different, an objective test called a NRI (Neural Response Imaging), to program the speech processor. I didn’t have to do anything. I was connected to the computer through a PSP, a more powerful type of processor, and sat reading as the computer beeped its way through the sound levels and measured the responses directly from the auditory nerve. Electrical activity from the nerve was recorded using the electrodes inside the implant and displayed on the computer (see photo).


Technical explanation of NRI test. Scroll down to figure 4 after the jump.

Non-technical explanation of NRI test.

The results showed my most comfortable level setting should be much lower. My implant was reprogrammed to the new settings, so I went from about 400 to 200 on the scale, across the board. This was a dramatic change – my volume was reduced by half!

I am still on the loud side with my new map, but it all seems so quiet – as if I’m in a dream. I was struggling to understand people (with lipreading). The balance of sounds was changed as well, so everything sounded odd and rather skewed. I was not happy at all. I tried switching to my old map after a few hours and it seemed horrifically loud.

We did a hearing test on the new map and that was -20db across the board, then we did another hearing test on my old map with the volume reduced, but it turned out I could hear nothing at 250, 4000 and 8000 mhz, so we scrapped the old map. I was given a second map, the same as the new quiet one, but a bit louder. I kept a programming slot on my processor for music, set to my new and quietest map.

We tried the Ling Six sounds after the mapping adjustment, I could hear them but I got completely muddled with these, which was quite upsetting, considering I had managed a Skype conversation the previous week. The Ling Six sounds are those sounds that lie within the speech spectrum of hearing; m, oo, ah, ee, sh, s.  On the positive side, voices did sound clearer, and sounds didn’t hurt any more. My audiologist said my current map is still on the loud side and we would be looking to turn it down even further.

A friend said to me, ‘If it doesn’t bother a hearing person, it shouldn’t bother you either’ – food for thought. I was not noticing sounds that bothered me previously and was actually struggling to hear them.

I also learned something handy. I had complained about the hiss when listening through the direct connect lead to my iPod. It turned out the correct way to use it is to connect all the equipment up first, THEN switch the implant on by inserting the battery. The implant then searches for the iPod or whatever the lead is plugged into, and there is no background hiss.

A few weeks on, there has been noticeable progress. I am able to hear all the quiet sounds as before – my office clock ticking, the photocopier spitting out paper in the room next door, and a recent weird one, the optometrist’s breathing as she checked my eyes. I am able to understand some speech again and when a story was read to me, I found it noticeably easier to follow. Last week, I had the oddest experience. I was in a meeting with a barrister; she spoke very clearly, not too fast, in short sentences (the stuff of dreams!). Usually I write notes, keep glancing at the CART/STTR screen, and lipread, to keep up. It’s pretty hard work. On a number of occasions I was able to *hear* what she said without lipreading, and quickly check the CART screen afterwards, rather than be a slave to it. It was such a lovely feeling. I experienced it again that afternoon with another client who was a bit loud, it was just like having captions shoved straight into my brain. No brain processing…. no panicking …. so effortless ….. so easy.

**screams excitedly and jumps around the room**




6 responses

12 07 2011

What you have to bear in mind is that the electronics don’t accurately reproduce the sounds they pick up. When someone suggests that you should hear what hearing people hear I think they are forgetting this. Or maybe not understanding it in the first place!
The sound that comes through your CI is an electronically processed approximation of the real world sounds that it picks up. It can’t imitate the adaptability of the human ear. Not even close.

I am having fun with mine, I am in month 8 now after switch on and getting used to using it. What has happened in my case is that my hearing has been rolled back in effect to the level I had in my early teens. Back then I was able to understand speech without lipreading at least part of the time and I was singing in the school choir. I am not yet about to burst into song but my hearing levels are approaching that area when I might be able to do so.

But, this is an electronic hearing instrument and it doesn’t reproduce sounds as faithfully as an ear and I am always hearing things that I can’t quite decipher. This is where the channels on the handset are useful. I have the Normal channel which is self explanatory and the Noise channel which is very effective in cutting out background interference. Then there is the Focus channel which cuts all noise out from behind me and focusses on the front. The fourth channel is Music which has an extra wide frequency range.

because I could already hear bass notes in music the CI supplies the missing top notes and so much music now sounds differently. I am having to releearn it all from scratch. I can sometimes recognise tunes on the radio. Most of the time I can understand speech on Radio Cornwall but not some other BBC channels. It’s a clarity thing. Using the Focus channel I can understand the radio in the car and van. Now that’s a first!

My chief obstacle at the moment is having to learn to listen again. In the past there have been many situations where I haven’t even tried to listen because I know I will have no chance.
Post-CI I am having to train myself to overcome this because now I CAN understand, it’s just that I have got into the habit of not trying. So now I am !

13 07 2011

That NRI beats all, doesn’t it? I haven’t had it, but I think I will ask for it to compare results with current mapping. Still having problems with grainy sounds. Feeling too pooped at the moment to jump around excitedly with you, but very please you are feeling that!!

15 07 2011

I wouldn’t beat myself up over not being able to tell when you are at the “most comfortable level” (mcl). I had fairly good hearing at one time yet I have great difficulty in choosen an mcl. Apparently I’ll put up with louder sounds when they are clear sounding (during the test). The levels were acceptable (not overly loud to me) but apparently were too high for my nerves. I have spent months recovering from that. At my next mapping I’m going to see if I can be tested with an NRI and see if that does better.The other problem I have with the mcl test is that as the frequency gets higher I have more and more trouble comparing levels as it is in the range of my tinnitus and it all just sort of merges together.

15 07 2011

Yes, ask for a NRI. My whole session with that took 2 hours. Your experience is so similar. It helps that you mentioned ‘clarity’ – I hadn’t thought of that. We need a list to help us explain sound to an audiologist – now where is Deb when we need her?!

16 07 2011

Glad to hear this is working for you Tina.

26 07 2011
Howard Samuels

Oh, Tina, I started out trying to push for more volume too, based on my experience as a hearing aid user. It never got to be so loud that my nerves were on edge, but lowering the M levels made everything more relaxing, and also more understandable. Of course, like any change, it will take you a while to get used to the new settings. But if your old program sounds horrible, you are already well on your way!

And this post is what I’ve been hoping to see from you – just hearing without effort! You’ve put in the work, and now you can reap the rewards.

As a bonus, you should see a little bit more battery life with your new settings.

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