How Cochlear Implants Work
Updated: Apr 18, 2018
Since the mid-1980's, cochlear implants have electronically stimulated auditory nerves to help people hear. A lesser known fact is they also apparently attract rude middle aged women.
“What’s that?!” The shrill question nearly shocked me off my stool at a breakfast restaurant last year when I realized a lady was behind me. It’s the kind of a question one may expect to come out of the mouth of a three year old at the zoo, not from a 65 - year old woman pointing at your head.
No, the lady was not wondering what I ordered for breakfast.
She was pointing in the direction of my cochlear implant.
I get it - cochlear implants have a certain mystique. They aren’t common enough for everyone to know what they are and how they work. Plus, they have magnets, and magnets are pretty damn cool on their own.
If you’re ever caught in the situation of having to choose between eating a delicious toasted english muffin and explaining the complexities of cochlear implants to a stranger, here’s a handy guide to keep the explanation quick.
The Very Basic Explanation
“Hi. This is a cochlear implant. I’m deaf and this helps me hear better.”
The Basic Explanation
“Hi. This is a cochlear implant. I’m deaf and it helps me hear better. It looks different than a hearing aid because instead of making sounds louder, it sends sounds to my auditory nerves through a tiny wire inside my head...Want to see how I can balance a bottle cap on my head?”
The Nitty Gritty
If those explanations aren’t enough, bless his or her heart. You’ve got one interested soul.
Let’s start with what they look like.
Most cochlear implants have four key features that rest on and just outside the ear - a microphone, a speech processor, a wire and a transmitter. The microphone and speech processor are housed in a little device over the ear that looks like a hearing aid. The transmitter is the magnetic headpiece that rests on the skull. A wire connects the processor and transmitter.
Here’s what you don’t see. Under the skin the cochlear implant also has a receiver located on the skull just under the skin near the ear and long electrodes that travel deep in the inner ear through the cochlea.
How it works:
When the cochlear implant is on, the microphone picks up sound and sends it to the speech processor.
The processor converts the sound to digital information and sends it through the wire to the transmitter.
The transmitter sends the digital message into the receiver under the skin through the magnetic pairing.
The receiver interprets the digital information and determines how much electric current should it should pass to the electrodes. The amount, position and speed of electric current determines the sound’s loudness and pitch.
The reciever passes electronic current to electrodes.
Electrodes stimulate auditory nerve in cochlea with electronic current.
Brain interprets signals as sound.
Pretty cool, right? Though cochlear implants don’t restore natural hearing, they help hundreds of thousands of people worldwide better understand sounds in the environment. They’re also becoming increasingly common in the US. The FDA first approved the use of cochlear implants in the mid-1980s to treat hearing loss in adults. Now, children as young as 12 months of age may be implanted. According to the National Institute on Deafness and Other Communication Disorders, as of December 2012, in the United States roughly 58,000 devices have been implanted in adults and 38,000 in children.
Back to breakfast
After catching my breath and drinking a few sips of coffee, I explained my implant to the woman. My fiance piped in about how much of a difference it's made in my life and how I probably wouldn't be able to understand people in the restaurant without it. By the end she remarked “oh, so that’s why I scared you!”
Well, it was probably more about a stranger suddenly pointing at me and coming up behind me than my hearing loss. But, I left that to be explained by another party. If only cochlear implants could filter out stupid comments..
Did I miss anything? Leave a comment. I'll cover more details on cochlear implants in other posts including auditory rehab and decorations. Subscribe to the blog below for alerts on the latest posts.