Cochlear implant mapping

4 05 2010

I’ve had 5 “mapping” sessions since activation. A mapping is a reprogramming of the cochlear implant, to readjust the electrical stimulation limits of the electrodes as each user’s brain adapts to sound and fibrous tissue grows over the internal implant. Mappings are typically carried out once a week for the first 6 weeks, then every few months, then twice annually.

At each mapping I was given increased volume and it was an opportunity to address any concerns with the audiologist. This was followed by a coffee break in the hospital cafe then a speech therapy session. I have one more mapping session this week, then my next one is in June when I have my 3 month check.

It’s been a rollercoaster ride. I’ve started with beeps and pushed so hard that I got a constant whine when I put the implant on. This set me back and I had to slowly build up my tolerance again of high frequency sounds from zero, bit by bit, and have successfully avoided a reocurrence of the whine. I have not yet reached full volume, there is still some way to go, which is kind of scary. I found last week quite difficult as everything seemed too loud and I started feeling stressed, but I hung in there and carried on wearing the cochlear implant until I got used to the increased sound levels.

Increased sound levels can be problematic for cochlear implant users because they are more sensitive to loudness changes. A normal hearing person can hear a wide range of sounds from very soft whispers to loud rock bands; this dynamic range of hearing is about 120dB (normal speech is within the 40-60dB range). However, a cochlear implant processor’s input dynamic range (IDR) or sound window is limited to an electrical current of 20dB, and 120dB of sound needs to be compressed into this. Therefore the cochlear implant user is more sensitive to changes in loudness than a hearing person.

If the IDR is small, sounds outside the IDR need to be omitted or compressed; sounds that are too quiet will be cut off, and sounds that are too loud will be compressed and will sound distorted. The 3 main brands of cochlear implants have different IDRs; Advanced Bionics has 80dB, MedEl 55dB, and Cochlear 45dB but with autoranging. I currently have my IDR set at 60dB.

What actually happens in a mapping session? I replace my processor’s battery with a direct connect input lead to the audie’s computer and put the processor back on my head. (Yeah, this freaked ME out the first time I did this).

The audie’s software will reprogramme my implant’s Harmony external processor.

My cochlear implant has 16 electrodes and when each one is stimulated, I will sense each stimulation as a beep.
The audie will set the Threshold (T) levels [to access soft speech and environmental sounds] and Comfort (M) levels [the amount of electrical current required to perceive a loud signal] for each electrode by judging the most comfortable and the highest stimulation I can tolerate – the most comfortable and loudest beeps I am happy to listen to.

I use the loudness scaling chart to indicate to the audiologist which level each stimulation correlates to, ranging from ‘Just Audible’ to ‘Too Loud’.

Then the audie ensures the M levels are similar in terms of my perception, so that the volume is the same in each electrode – I was able to tolerate very high levels of high frequency sounds this week but she brought these back down, otherwise everything would have sounded weird and unbalanced.

This mapping method is rather tedious and drawn out over several months. Clarujust is new software (currently in FDA trial) from Audigence Inc where the patient and processor are interfaced to a computer and words are played and repeated as heard, the software adjusting the map accordingly. Mapping this way reportedly takes 30 minutes. This software can be used by all hearing aid and cochlear implant companies except Advanced Bionics, however Phonak signed up with Audigence Inc this year prior to the Advanced Bionics/Sonova acquisition.

When a mapping is new, it tends to sound louder, until I get used to it. It takes 3 days to get used to a new mapping, then I find loud sounds have become softer and more tolerable, and I can hear a wider range of soft sounds. It is uncomfortable turning up the volume of life to the max every few days. I still have to brace myself for the jolt first thing in the morning, making the transition from complete silence to a full technicolour river of loud sounds pouring into my brain. Amanda’s Tip of the Day: If you wake with a hangover, take your time to put on your CI and turn down the volume. It helps. A little.

It’s an amazing learning process as I am also trying to identify sounds as well, discovering amazing new ones, and learning to discriminate between things that sound similar to me. My hearing is like a baby, it needs time to learn and grow, but it can be fun too.

Erber’s model set forth 4 levels of auditory skill development;

    Awareness of sound (presence v absence)
    Discrimination (same v different)
    Recognition (associating sound/word with meaning)
    Comprehension (using listening for understanding)

I have now reached the second level, I am hearing things but finding it difficult to discriminate between some sounds. Obviously, this means I am still lipreading. In my speech therapy session this week, I discovered I can’t distinguish between Gear v. Dear, tIme v. tAme. I can listen and fill in a word missing in a written sentence, but listening to a whole sentence and being given one written word is more difficult. With hearing aids, both tasks would have been impossible.

In addition to mapping, my progress is occasionally evaluated with an audiogram and speech perception performance with the cochlear implant in a soundproof booth. These tests assist the mapping process and indicate any further adjustments required. I expect I’ll have this done this week, and hope to have improved upon the 18% I achieved in my last speech perception test.

I was programmed with ClearVoice last week but am still adjusting to my new mapping, so I have just been ‘tasting’ this wonderful addition. I tried it on the train; the roar of the train engine and clashing sounds (brakes or pressure pads? – haven’t worked this sound out yet) dropped away significantly and I could clearly hear voices around me. It was awesome. Yesterday, I was sitting by a window and became conscious of this sound. I realised it was the rain spitting outside. In the garage, I could hear the drumming of the rain on the roof and the traffic outside. With ClearVoice on, the traffic became very quiet and the rain became a very clear high PLINK PLINK PLINK, and a lower PLONK PLONK when it came through a hole in the roof and landed on an object. Again, awesome!

Try out the ClearVoice demo for yourself. Don’t forget to say the mandatory WOW!

Shanti is waiting for her cochlear implant operation date and works as a personal trainer and complementary therapist. She gave me a super aromatherapy massage yesterday and I left feeling very relaxed. As soon as I left, I plugged into my iPod and was amazed to hear that the tinny / Donald Duck tone of vocals had gone from a lot of songs. Perhaps there is a link between relaxation and better hearing. Today, voices sound largely normal and it’s so so so NICE to have some normality again!

Photos courtesy of Byron




14 responses

4 05 2010

Hi Tina,
Another great post. You’re doing really well. I met with Pidge the other day and had a really good chat. She is doing so well too. I hear you are meeting up soon too?
Looking forward to catching you up on the hearing stakes soon 🙂
Nice to read how the CV works. I think that is going to be a real must for me in my gym environment.
Best wishes,

4 05 2010

Graham – I’m looking forward to watching your progress on See Hear! I can’t wait to meet up with Pidge and see for myself how she’s doing – we’re meeting this week. You’re going to love CV. And I haven’t even tried it on the maximum setting yet, I think that will be ideal for noisy social events.

4 05 2010

Hi Tina,

So great to hear about your progress. Reading your posts is making me very impatient! I had the operation last Wednesday and the activation is scheduled for May 14th. I am curious have you started wearing you hearing aid yet or are you still just on the CI. I am interested to see when you can start combining the 2 different technologies since I am pretty much in the same boat as you. In the meantime, please keep up the posting because don’t you know some of us are living vicariously through you. 🙂


5 05 2010

Hi David
Hang in there! I am very impatient too. I can see how much you want it. It’s going to be so exciting. The best advice I can give is to take it one day at a time and don’t have any expectations, just go with the flow. Are you going to video your activation?
I am only wearing the CI. I haven’t worn the hearing aid in my other ear for 2 months now. I want to wait until I am happy with my CI before I try the HA again. I have a feeling I am going to bin the HA. We’ll see!

5 05 2010

Hi Tina,

Hmm, hadn’t thought about doing a video of the activation. I did take some pictures of me with the head bandage and then after the bandage came off. It would be easy for me to do the video since my fiance will be there to watch. Maybe I will ask her if she can videotape it. It might be a fun video to watch later on. Interesting about ditching the hearing aid. My hearing is still not too bad with my good aided ear so I think that might be too hard for me to imagine doing right now before my activation. Who knows, my perspective may change dramatically after activation. We will have to wait and see. Thanks for the advice. Just saw the surgeon today for a post-op and I told him the same thing about waiting. He told me I was lucky I don’t have to wait for 6 weeks which is what they originally did. I can’t even imagine that. Take care Tina and keep me posted.


5 05 2010

Hi David, I know about being impatient! My op is next week on the 13th May and like you reading everyone’s progress is frustrating. I wanna have it all NOW.
Good luck with the switch on.
I have been told I should try to use the HA as well as CI but will see how it all pans out.
Good luck with the switch on 🙂

5 05 2010

Graham & David – Another little thing. You’ll make quicker progress with neural development the more you wear the CI. I wear mine for 16 hours a day and keep the volume at 12 – sometimes I just have to grin and bear it. It’s not a bed of roses at first but I think you know this. I know of one person who wears her CI for about 15 minutes a day and is not making progress. I’m really hoping you guys do amazingly well!

5 05 2010
laura j

wow it seems you are doing well on your journey! you will be hearing lots more sounds now eh? 🙂 im quite used to maps so much now i hate them! haha i hate it when it goes back all roboticy again and i have to get used to it. i may be getting the N5 next yr so i look forward to that and wont mind the map change if it helps me hear any better although i dont think i could possibly hear any new sounds by now!

happy listening! 😀

6 05 2010

Hello David, you should definitely do an activation video. Not only is it an emotional moment in itself, and worth doing so that you remember everything (it’s a bit like getting married, it passes in a blur) but it’s also a good benchmark for speech. Not everyone’s speech changes – or any differences which develop might be minimal, or come later in the process – but my speech has changed noticeably, apparently, and the difference between the video and now is heard by everyone who’s watched the video.

I find it difficult to watch now though. It makes everyone blub!

Definitely second the advice about wearing the CI all day, though I take mine off maybe about half an hour before actually going to sleep: “winding-down” time works for me, but again, everyone will have a slightly different response to taking it off.

11 05 2010

Hi everybody, Im having rough ride right now, sort of everything from louder Tinnitus, and so so so so Tired, Now today 11th May Ive got severe Headache so Switched off Cochlear impant (Med-el Opus2) I was in Cofort Zone yesterday when being tuned in for 4th time, But this morning its all Different.

Im not going to give in, thats not me, BUT!! its a relief when its switched off, but I guess you have all done it sometimes??

regards and good hearing


11 05 2010

Hi CJC – Nice to see you on here! Hope you feel better soon. I was talking to a CI buddy and we were discussing this push we have from Day One. We felt it is a lot to ask of our brains, to adapt so quickly in such a short time and keep turning up the volume. It takes a few days for the brain to adapt to each mapping so it seems to be all push, push, push, and no time to take it all in. I think the tinnitus is just protesting at the change and saying ‘Hey, I’m still here!’ but hopefully it will go soon. Mine went after a month with CI, sometimes it is there a little when I take the CI off. Hang in there, you’re so positive, you’ll make it.

23 05 2010

Well folks,

After reading and dreaming of nothing but CI’s. I’m going to take that quantum leap into the unknown and see if a CI will bode with thyself.

I have a feeling this CI family is getting bigger by the minute. lol

25 05 2010

Bluesky, let us know how you get on. And welcome to the family! You’ll find lots of us on HJ – see ya there.

17 04 2013

With the n5 remote, when ever I lower the sensitivity and volume button to 0 does it also reduce the dynamic range.?

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