Did You Ever Wonder... How Do Hearing Aids Work?
It seems amazing that this tiny device can be put in your ear, that will bring all the sounds you've been missing back to you. If you suffer from hearing loss, you may feel like your hearing is gone forever. But, with the help of this little electronic aid, you can hear again.
So, how do hearing aids work?
Even though there are lots of different makes and styles of hearing aids, they all work in basically the same way. They take sounds from outside, amplify the signal, and reproduce it at a higher volume inside your ear so that you can hear it.
Every hearing aid consists of at least a microphone, a receiver, a battery and a circuit. Most modern hearing aid models contain much more than just these parts, but first let's discuss these to see how it works.
The hearing aid is basically an amplifier. The microphone picks up the signal from outside. What happens next depends on the make of the hearing aid. There are two categories; analog and digital.
With analog hearing aids, the signal is changed into electronic impulses. These impulses to the circuit, which raises the volume to the desired level set by the user. Regular analog hearing aids simply amplify the sound, but with a programmable analog aid you can do much more.
Programmable analog hearing aids are pre-set by your audiologist to multiple settings, which you can choose between according to the situation. There is a switch which controls the settings. For example, you might have a setting that is made for noisy places. If you find yourself in a noise environment, you can switch on this setting, and it filters out all the excess noise.
Digital aids are even better. They have a tiny computer chip inside the device, which analyzes the signal and adjusts it according to the user's settings. Do you see why digital hearing aids are so much costlier?
Finally, after the signal is amplified, modified and whatever-else-ified, it comes out of the receiver as sound, into the inner ear.
The different styles of hearing aids all operate according to the same principle, but with slight variations. There are three broad categories:
Behind-the-ear (BTE) - With these hearing aids, the device itself is behind the ear, and a tube transmits the signal to a plastic mould that sits inside the ear.
In-the-ear (ITE) - These are smaller and fit entirely in the ear. You can use several different features with these, such as an adapter for telephone use. They are smaller and more delicate, but basically work the same way.
Canal hearing aids - This includes in-the-canal (ITC) and completely-in-the-canal (CIC) aids. These are the smallest and most delicate hearing aids, and are placed much deeper in the ear. They must be customized to fit the wearer's ear exactly.
There is another, less common type of hearing aid that actually vibrates against the bone and sends the signal to your inner ear. This is called a "bone conduction hearing aid," and is used for those who have severe hearing loss, or suffer from a condition where the ear canal is blocked or destroyed.
It works like this: The device picks up sound in the same way as regular hearing aids do, using a microphone. It translates the sound into a signal, but instead of using a receiver, the bone conduction hearing aids use an oscillator, which produces a vibration. The vibration is felt in the skull, and the inner ear perceives it as sound.
Bone conduction hearing aids are not so common and are only worn by those who need to use them.