The New Envoy “Esteem” Fully-Implanted Hearing Aid

by Neil Bauman, Ph.D.

A lady asked,

Do you know anything about the new “Esteem” device? The ad says it is an implantable device that needs nothing outside the skull. As far as I can tell (without understanding what the ads are saying) it might be a replacement for a CI. What can you tell me about it?

What you have seen advertised is the new Envoy “Esteem”. Basically, the Envoy “Esteem” is a hearing aid that is fully implanted in your head. It uses some great technology in some areas and not so great technology in other areas—but it is just a hearing aid. It is not anything like a cochlear implant (CI).

One of the good things about this technology is that it uses your outer ear and ear canal to collect and filter/amplify sounds naturally rather that using an artificial means such as a microphone. That’s good.

Another good thing is that since it is all in your head, it is totally waterproof. You can swim with it and never worry about water leaking into it and shorting it out.

On the other side of the coin, there are some things I don’t like about it. First, they “break” the ossicular chain. In other words they pull the 3 bones apart so the hammer’s vibration no longer is directly coupled to the stirrup via the anvil. Basically, they cut the anvil out of the chain. What this means is that you lose your residual hearing (apart from bone conduction). Thus, if your battery dies, you essentially go deaf. You can’t just use your residual hearing until you get the battery replaced.

There have been other designs in the past that used what I consider a better design—which was NOT breaking the ossicular chain so your residual hearing remained intact—and then the hearing aid amplified the sounds you needed. I wish the Envoy “Esteem” had used a similar approach.

Here’s how the “Esteem” works. What they do is fit a sensitive transducer to the hammer (the first of the three bones in your middle ear). When the eardrum vibrates, it vibrates the hammer and the transducer attached to the hammer converts this vibration into electrical energy—just like a microphone does. The sound signal is processed just like it is in a regular hearing aid and then the output is sent to another transducer that is attached to the stirrup (the third of the three bones in your middle ear). This transducer works exactly the same, but in reverse, to the one on the hammer. It takes the electrical signal and converts it back into vibrations that causes the oval window to vibrate in the normal manner—albeit at a “louder” volume so you can hear better.

You accomplish exactly the same thing with a regular hearing aid—injecting an amplified signal into the ear canal thus making the eardrum vibrate more vigorously, which in turn makes the three bones vibrate more vigorously and thus down to the oval window. The only basic difference is that in the Esteem this is all done
internally, not externally. The Esteem amplifier and battery are surgically implanted in a hollowed out portion of the mastoid bone behind your ear.

Note that that Esteem is just a different kind of hearing aid, and as such has the same limitations of other hearing aids. For example, it cannot give you back discrimination if you have low discrimination (word recognition) scores.

Furthermore, it cannot use techniques such as directional microphones and noise-canceling microphones.

The Esteem has a remote control so you can adjust the volume and turn the aid off if you want to.

Apart from the battery dying and leaving you deaf, there are a couple of other downsides to this device. One is you need an operation every few years to replace the battery.

Two is that as technology improves, you are stuck with old technology in your head—much like people with CIs are. Sure the software can be upgraded, but not the device itself without an operation to replace the implanted parts, with its inherent risks.

In addition, you can’t directly couple this hearing aid to any assistive devices—there is no t-coil (or even provision to have one)—so you will not be able to use room loops, neckloops, etc. unless you get a separate loop receiver and use earbuds to get the sounds into your ear canals. (But since you can do that, and there are loop receivers readily available, this isn’t really a problem—you just need to wear an external loop receiver.)

Theoretically you should be able to use bluetooth devices “normally”—you’d wear a bluetooth receiver hung on your ear like everyone else does and the sound will be captured by the Esteem and amplified just like any other sounds entering your ear canal.

Learn more about the Envoy “Esteem” here.