Our brains work similar magic when we turn sound into language.
Getting a second cochlear implant – It’s all about the brain
Thursday, August 25, 2022
So much of my understanding of my cochlear implants relates to the brain. It’s also been the most useful way for me to explain my implants to other people. I talk about my implants a lot — to people who have never seen one before, to other people who have them, and to people who are aware of them, but aren’t quite sure what to think of them or how they work. To me, my implants are simply providing my brain with information that my ears are unable to provide. It’s up to my brain to make sense of everything.
The internal part is surgically implanted into the inner ear and includes a thin electrode array. The external part includes a headpiece that attaches to the head via a magnet, and a sound processor, which is a small device either worn on the ear (similar to a hearing aid), or it can be clipped onto a shirt.
Hearing or seeing vs. understanding
People with normal hearing, or people who had normal hearing for a very long time before losing it quickly, sometimes don’t make the connection between the brain and hearing. They think that hearing is something that just happens naturally. They think that if someone can hear something, that means they can understand it.
Someone who has lived with hearing loss for a long time, however, usually understands quite well that hearing is not the same as understanding. When I was in college, I read “Cosmos” by Carl Sagan, and the following passage about reading caused me to appreciate what my brain was doing in a new light:
"What an astonishing thing a book is. It's a flat object made from a tree with flexible parts on which are imprinted lots of funny dark squiggles. But one glance at it and you're inside the mind of another person, maybe somebody dead for thousands of years. Across the millennia, an author is speaking clearly and silently inside your head, directly to you. Writing is perhaps the greatest of human inventions, binding together people who never knew each other, citizens of distant epochs. Books break the shackles of time. A book is proof that humans are capable of working magic."
Our eyes see a flat object filled with funny dark squiggles, but it is our brain that interprets what our eyes see, and takes us on the magical journeys into the mind of another person, or to another time and space.
Our brains work similar magic when we turn sound into language. If our brains don’t learn how to understand language or discriminate between sounds, auditory inputs can be similar to hearing a different language. There is sound, and there is hearing, but no understanding. It’s like looking at “funny dark squiggles” instead of reading coherent sentences. But if our brains learn how to hear, similarly to how we learn to read, then it happens automatically — without our even being aware that we are doing it.
The reason I like this passage so much is because it really made me aware of how easy it was for me to take eyesight, my brain, and the ability to read for granted. It also reminded me how much I was also relying on my vision to help me understand speech. When I was growing up with my implant, captioning wasn’t always available, and I remember trying to explain to my friends’ parents that even though I could understand everything that they were saying, I still needed captioning to understand movies or television. I remember being asked “if you can hear me, why can’t you hear the TV?” No answer I gave seemed to satisfy them; it just didn’t make sense.
Hearing with my first cochlear implant
My hearing journey is as unique as any. Even though I could have qualified for bilateral (two) implants when I was first implanted in 1999, I ended up waiting nearly twenty years between implants. So, there is a huge difference in how I hear on one side compared to the other. In the context of how I understand it, it’s more useful for me to put it like this: there is a big difference between how my brain is able to use the information that it is getting from each device.
My old implant, on my right side, has been with me since I was ten years old. I had progressive hearing loss for eight years, and my parents did a great job of making sure I always had the most appropriate hearing aids. So, my speech and language developed pretty well.
My brain was definitely working a lot harder in order to use a deteriorating quality of auditory information as my hearing declined, but my hearing aids helped me to stay afloat. When I got the implant, I had only been functionally deaf for about a year, so my brain had tons of auditory memory. The neural connections were already there to be taken advantage of.
When I used visual cues, such as with speechreading, it was easier for my brain to translate the information from the implant into what my brain knew it was “supposed” to sound like. Because of this, everything sounded very normal, pleasant, and very natural. My brain was also relatively young at the age of 10, which means that it was more plastic — able to adapt and change quickly to the new electrical stimuli it was receiving from my cochlear implant. In the audiologist’s sound booth, this ear alone gave (and continues to give) me 99% understanding of sentences in a quiet environment.
Getting a second implant 19 years later
Getting my second implant was a completely different experience. Instead of being 10, I was now 29 years old, and it had probably been more than 21 years since my brain actually heard well with my left ear. It was just so much harder for my brain to use the information from that ear.
For the first two years, I would probably describe the sound quality of my left ear as being unpleasant. It wasn’t exactly hard or challenging, but sometimes my ears would feel unbalanced. Or I would feel that the sounds in my new ear weren’t helping me at all because there just wasn’t a lot of clarity yet. Even today, four years after implantation, sound isn’t natural or pleasing to listen to. It’s hard to describe. It’s not really echoey or metallic, but in the absence of better words to use, this is the only way I can explain it.
Things that are pleasant in my old ear are harsh or shrill in my new ear. Sounds in the high frequencies don’t really sound like sounds, but more like a sensation. Not a painful or uncomfortable sensation, but it seems like I’m feeling some of the higher frequencies more than hearing them. In contrast to 99% with my old ear, my understanding of sentences in quiet is only 28% in my new ear.
Hearing with two cochlear implants
But what I just described is just if I’m using my new ear alone. Most of the time, I’m using both ears together, and the result is almost magical. When both ears are “on,” my brain produces this amazing fullness and richness of sound that my one ear alone never quite gave me.
Even though sounds have always been so pleasant and natural in my old ear, I now find it to be noticeably less “rounded” if my new ear is off. The ear that has always given me a very pleasant and natural sound actually sounds less natural now without my new ear.
I’m using both ears together, and the result is almost magical.
The power of habit is quite strong, so I still find myself sometimes only putting on my old ear to start the day. Especially if I wake up a little too late to enjoy a silent cup of coffee before attending to a noisy toddler. But I’m becoming so much faster at putting on my new ear, because it has become so obvious to me how much my brain likes having that second source of information!
I’ve never been the type of person who tries to force things along, so I haven’t done a lot of training to hear only with my new ear, even though, in hindsight, it probably would have helped. But there were times that it just naturally happened, like if my battery died in my old ear while I was listening to a ballgame on the radio, and I was able to actually understand a few words with my new ear alone. I had a lot of context clues, since I knew I was listening to a baseball game, but it was so exciting to know that I was actually making progress.
It took about 18 months for me to actually want to put on my second sound processor, because I truly felt that I was hearing better. For those first 18 months, I was basically just operating with the mindset of: “My brain is probably learning what to do with this new information. Won’t this be interesting?”
Two years later, I’m well past the point where I don’t like the thought of leaving home without my new ear on, because it makes my hearing so much better — especially in louder environments. When I look back and think that I spent almost 20 years without it, I can’t believe how much harder my brain must have been working.
In my most recent audiological visit, my new ear by itself had the largest leap forward in understanding yet. I went from 0% to 9% in one year, then up to 12% for year two, 18% for year three, and now up to 28%. I don’t know if it was because I was putting on my implants earlier in the morning due to the baby, or if it was because my brain was forced to work harder due to the prevalence of mask-wearing at work during the COVID-19 pandemic. But it just seems to be getting better with time. Having an open mind, keeping my expectations in check, and using words such as “interesting” rather than “good/bad” has made a real difference for me.
Grateful
So, even though my brain has had a very different experience with each implant, overall, I’m very happy with both of them. And my brain is, too. It’s been really cool to experience my brain re-learning how to hear in my new ear, and how much that second ear adds to the overall experience, even with the huge difference in sound quality.
It’s been such an interesting journey. When I really think about what I’ve been able to accomplish with a small electrode array replacing my natural hearing, I’m just left in awe of what the human brain is capable of. And when I consider how the cochlear implant system itself was the product of the combined efforts of a whole bunch of other people’s brains collaborating over the course of a few decades – engineers, audiologists, surgeons all used their brains to give me this wonderful technology … It's just amazing.
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