Quora Question: What Does a Deaf Person With a Cochlear Implant Hear?

Chilean Patricio Villablanca, left, shows his 6-year-old son, Dan Villablanca Vega, the sound controls for the cochlear implant Reuters

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Answer from Cristina Hartmann, author, cochlear implant user since 1991.

I know what I hear with a cochlear implant (CI) is a far cry from natural hearing. In an abstract way, I know the sound I hear is highly digitized and pixelated, but I have no other frame of reference for understanding sound.

Learning how to hear with a CI, particularly for someone born profoundly deaf, isn't an easy or simple journey. I don't regret going on the journey, but there were no roses or rainbows along the way.

Before the Cochlear Implant

I was born profoundly deaf. My deafness was so severe that no hearing aid on the market was any help. I thought they were toys and would feed them to my dog, to my mother's horror. The only sound I could sense was some vibrations from very loud noises. I was off the charts in terms of dB loss, which is relatively rare.

Once my mother understood the profundity of my deafness, she decided to abandon speech training in favor of sign language. The extent of my speech training was teaching me not to make sounds during inappropriate times, like church services. (This is called the "voice off" mode.)

Through sign language (initially Signed Exact English, then American Sign Language) and reading, I had access to visual languages. By six years old, I was perfectly on par with my hearing peers in terms of language development, albeit visually, not auditory. My brain was functioning quite well; my ears weren't.

I knew there was a thing called "sound" in an abstract way. It was kind of like how you know there are atoms and electrons, even though you can't directly see or touch them. Seeing others move their lips and understand each other seemed almost magical. I considered it close to a form of mind-reading that I wasn't privy to.

In 1991, I became one of the first few hundred children to receive a CI after the FDA approved it for pediatric use. I was six.

Neurologically speaking, I was far past my prime. Doctors didn't expect me to learn how to speak or listen.[1] Considering the profundity of my deafness and my advanced age, doctors didn't quite know how well I would ever hear. Most of the children who received a CI during the clinical trials once had hearing. I was uncharted territory at that time, so the doctors warned my parents not to expect too much. In 2014, the field of auditory training for children with CIs has developed by leaps and bounds, so my case wouldn't be as much of a conundrum today.

The Beginning of the Cochlear Implant Experience

About a month after the surgery, I returned to New York City to get my CI turned on.

It was in a windowless room in a cramped hospital on the Upper East Side. The audiologist and my mother watched me as they turned on the external processor.[2] After the audiologist placed the magnet on my head and turned it on with her computer, it was game time.

And ... nothing.

I didn't hear or feel a thing. My brain wasn't capable of processing the new stimuli, so it simply didn't. This seemed very wrong to me, so I ran down the hall, screaming. With my six-year-old logic, I thought I just needed a louder noise. Still nothing.

Disappointed, my mother and I left the hospital wondering if the surgery had been worth it at all. As we waited to cross the street, someone started a motorcycle behind me, and I felt something. I couldn't even quantify it. It wasn't tactile. It wasn't visual. It was painful, like sharp prickling somewhere in the depths of my brain.

That was the first sound I "heard." I was not impressed. It was so painful and bewildering that I wanted to cry. Suddenly, I had this foreign sensation in my mind that I couldn't make sense of. It almost felt like an invasion. Sound - the furthest thing from magic I could imagine.

With time (and my parents' insistence that I keep my CI on), the sensation became less frightening, and more familiar. Sound, however, never became natural or completely comfortable. It was (and still is) a chore to hear, more akin to taking out the trash than playing.

I proceeded to spend hours every day in intensive speech therapy simply learning what sound was and how to interpret what the differences in sound meant.

As part of my training, my speech therapist vocalized common syllables like aaa, ahhhh, ssss, ssshhh. To test my comprehension, she laid out three cups that represented three different syllables. After she vocalized one (with her mouth covered), I would have to choose the right cup. She made training as fun as possible, but it was still work.

Slowly, I began to understand that different sounds could be translated into words and sentences. It was a long and arduous process. It took me nearly three years before I could understand the most rudimentary spoken sentences. My listening skills were at the level of a two-year-old as my writing and reading skills were a decade ahead.

Frankly, I hated learning how to hear and listen. It took hours out of every single day ... and mind you, I was still a child. The last thing I wanted to do was spend even more time cooped up with adults in windowless rooms when my friends were out playing. (Always windowless. Always.)

By nine, I was starting to speak, laboriously and unintelligibly. Instead of simply identifying my speech therapist's vocalizations, I would repeat them back to her. Once I (somewhat) mastered the syllables, my speech therapists would read children's books aloud and I would repeat the words back at her. It wasn't until I was 13 that I felt confident enough to speak in public. Now, I speak nearly every day.

This artificial way of learning how to listen and speak has affected how I think about speaking. I wouldn't say that I listen to my own voice as hearing people do. Rather, I focus on the physical act of speaking (tongue positions, air flow, etc.) as I'm speaking. So, it's a different cognitive process. I still need instruction on how to pronounce new words, particularly words with foreign origins.

That is how I learned to speak and listen.

What I Hear Today

I know what I hear with a CI is different than natural hearing. I miss things that others don't, but I don't know exactly what I'm missing.

Not only is the range of frequencies much more limited with CIs, but subtle differences in intonation and pitch are flattened. It's like looking at a very pixelated painting; you grasp the gist, but the nuance is completely lost.

Here's a CI simulator.

As you can probably hear, what I hear is quite different from natural hearing. One of my hearing friends described the simulator as Darth Vader. Well, that's my auditory world ... Darth Vader wheezing. Good thing I think he's a cool character.

The low resolution form of hearing affects a lot of things: my speech comprehension, my speech, and sound interpretation.

The sound pixelation makes it hard for me to differentiate sounds of similar frequencies. Low frequency sounds are particularly problematic for me since CIs are more attuned to higher frequencies. For example, if there is low-frequency background noises, it'll be very difficult for me to understand male voices.

Functionally, I'm hard-of-hearing.

The digitized sound that the CI provides also affects my speech. A kind way of describing my speech would be somewhat halting, robotic monotone. I do not have the "deaf accent," but I have a completely unidentifiable accent. People constantly ask me what country I'm from, and become very confused when I tell them that I was born and raised in the United States.

Even now, more than 20 years after implantation, listening and speaking involve cognitive work. I don't hear every syllable, so there's guesswork involved. If you say, "Hello, Cristina. How are you?" I'll probably hear something like, He-lo, Cr-tina. Ow --- U? It takes me a few moments to fill in the spaces, and sometimes I make mistakes.

Another aspect of hearing with a CI is the ability to turn off sound. Since I don't sleep with my processor on, every morning I must brace myself for the deluge of noises. Even in quiet environments, there are hundreds of small noises, the refrigerator humming, the breeze blowing outside, even your own breathing. They're white noise, inconsequential to most people, except me. It takes time for my brain to filter out the white noise, and until that time, it's almost a painful experience of overstimulation.

That is, more or less, how I hear with a CI.
[1]: This phenomenon is called Neuroplasticity. It has to do with the ability to create or change neural pathways and synapses. The older we get, our ability to create and change our neural pathway becomes diminished.
[2]: CIs have both internal and external components. Cochlear implant

N.B. For everyone who reads this, please do not take my experience as a predictor for other children with CIs. There are a lot of individual variables involved: age, cognitive capacity, language acquisition, among others. Considering my age, I perform fairly decently with my CI, but others outperform and underperform me.

Author's Note: this article focuses on the process and sensation of hearing with a CI. There is, however, a cultural component to receiving a CI. See here for more details: Cristina Hartmann's answer to What is life like after a cochlear implant (bionic ear) for a person born deaf?