How to Optimize your CI’s MAP

First, if you’re a geeky type (like me) and want to know a lot about how a CI works, get Jace Wolfe’s book: “Programming Cochlear Implants” for $40 on Amazon. If you’re more normal, the following will most likely be sufficient. And you can always send me questions via email.

Most folks have two objectives in improving their MAP (how your audiologist sets up (MAPs) your CI): vocal quality & speech comprehension.

Vocal quality: voices sound scratchy, have echoes or… Over time, many folks adjust to the sound, though a new MAP can improve things.

Speech comprehension can be measured by your audi, but it’s usually in a sound booth (not the real world), and your brain won’t have time to adapt to a new MAP before testing.

Best real world speech comprehension will likely not be with the best vocal quality.

Unfortunately, optimizing a MAP is not straightforward. You want an audi that will work with you, listen to you, is skilled, and is lucky. Don’t be shy getting a tune up from a different audi or different CI center. She can read the programs from your processor & make changes with no need to contact your previous audi.

It’s good to start with the stim strategy that works best for most folks: F120-S (also called HiRes with Fidelity 120 Sequential). F120 is the only AB strategy that can use the new Clearvoice noise reduction algorithm which has gotten rave reviews. Theoretically F120-S is better than F120-P, and in studies, folks have performed better with F120-S than F120-P, but that doesn’t mean that you should not try F120-P. It can take as long as a month to adapt to a new strategy, so give yourself time to adjust to F120-S.

The most common & important adjustment is setting your M (Moderately Loud but Comfortable) levels. Your audi thinks of it as setting the loudness of each electrode. But what you really want is that all the speech frequencies are equally loud, and that’s slightly different. On this site is a “CI calibrator download” (mp3) that beeps sequentially at 16 important speech frequencies. You want those 16 beeps to be roughly equal loudness. If a beep is too soft, you’re missing those speech frequencies. If a beep is overly loud, you’ll turn down the volume and reduce hearing all the other speech frequencies. It’s nice that at home you can see if it’s time for a tune up.

The next most important setting is IDR, and unfortunately each person has to experiment to see what works best for them. Set a different IDR in one of your program slots to see which works better for you.

An 80 IDR is not the maximum. You can get a higher effective IDR by manually setting your T’s to 20% of M’s instead of the default 10%.

And finally, I think there may be a small benefit by using a 39.5 uSec pulse width. It has the side benefit of increasing battery life.

Another consideration is how the beeps sound. Some folks say their highest frequency electrodes are overly shrill, or painful. The audi can shut off those electrodes, and AB’s Soundwave software will adjust which frequencies go to each electrode so that the high frequencies are not lost, but sent to electrodes that are working well for you. You should still hear all 16 beeps, even if some electrodes have been shut off. The frequency of each beep is listed by the calibrator so your audi knows what to adjust.

Be observant. In which situations do you have difficulties hearing? Try to bring mp3’s, or DVD’s (movies), or your cell phone to your tune up that shows the problem. This will help you decide if the new MAP is better.

If you have a spare processor, you have 6 total slots to try things and see how they work when you have the time to really evaluate them in the real world. If you don’t have two headpieces, this is not as good an option.

Keep your best previous program in a slot to compare with the new MAPs.

But getting a good MAP is only the first step. Speech has much redundancy, and your brain will learn what features of speech provide the best comprehension. When you change your MAP, your brain will need to adapt, and this takes time. You can greatly improve your performance (and shorten your adaptation time) by doing listening exercises. The listening room at hearingJourney.com is good. Books on tape and other rehab sites are other options.