Hearing loss is a common condition, the frequency of which increases with age. Many people go through much of their lives without ever thinking about hearing aids, then feel completely lost the day they have to buy a pair.
Perhaps after your hearing test, your audiologist told you that hearing aids would be beneficial for you. There are hundreds of models, many of which feature particular functions and technologies that can be very useful... or completely superfluous. Add to that often exorbitant prices, and it becomes difficult to know what you really need.
One of the best ways to become an informed consumer is to better understand the product you are looking for. Here is a detailed examination of how hearing aids work, the different types available, the features you can find in them, and, more generally, everything you ever wanted to know about these small hearing devices.
Components of a Hearing Aid
Hearing aids have evolved enormously since their invention. The very first device for people with hearing impairment was the ear trumpet.
The ear trumpet was essentially a large cone that channeled more sound into the ear. These devices were bulky, cumbersome, and very impractical. Imagine having to carry around a trumpet about the size of a traffic cone everywhere you go.
Today, hearing aids are small, powerful, and capable of amplifying sound much better than the trumpets of old.
Depending on your lifestyle, personal preferences, and the sound environments you frequent, the ideal product will not be the same. Here is a more detailed look at how hearing aids work and the key components that enable them to help people with hearing loss.
The Microphone
The first component to examine in a hearing aid is the microphone. The microphone is an electrical component capable of converting the vibrational energy of sound into an electrical signal.
Microphones used to be quite bulky, but today's can be smaller than a coin while still retaining enough sensitivity to capture good quality sound.
The Amplifier
The next component can be considered the brain of the system: the amplifier. The amplifier, or amp, increases the power of the signal received by the microphone.
Hearing aid amplifiers can also perform additional functions, such as voice isolation or background noise reduction. These functions rely on slight manipulations of the signals from the microphone and greatly facilitate understanding conversations in noisy environments.
The Speaker
Once the digital signal is amplified, the next step is to transcribe it into a medium that the ear can use to perceive sound. Conventional hearing aids use a speaker for this. A speaker consists of a diaphragm and magnets.
When an electrical impulse passes through it, the current causes the diaphragm to move, producing sound. Since the signal is only an amplified version of what the microphone captured, the speaker reproduces the same sounds, but at a higher volume.
Hearing Loss
The ear is a complex organ. One of the best ways to understand hearing loss is to take a closer look at the ear's two main functions: sound conduction and sound perception.
The Conduction Pathway
Sound conduction refers to the ear's ability to translate variations in air pressure, produced by sound waves, into physical movement. The parts of the ear involved in conduction are the ear canal, the eardrum, and the ossicles of the middle ear.
The ear canal carries sound to a thin membrane called the eardrum. Tiny ossicles connect the eardrum to the sensory organ of the ear. When the eardrum moves, it causes these small bones to move.
A problem at any stage of this pathway can lead to a form of hearing loss called conductive hearing loss. Many of its causes are treatable, such as a buildup of earwax.
Sound Perception
The sensory aspect of hearing involves the conversion of physical movement into nerve impulses. The main element responsible for this function is the cochlea.
The cochlea is a hollow, snail-shaped structure that contains a multitude of sensory hair cells, each finely tuned to a precise frequency. When the ossicles strike the cochlea, they propagate a vibration through this hollow structure and activate the corresponding hair cell. This hair cell bends, triggering a nerve impulse that the auditory nerve carries out of the ear. The vibrations are then processed by the auditory centers of the brain.
Hearing loss related to the cochlea, auditory nerve, or brain is called sensorineural hearing loss. These forms of severe hearing loss are generally irreversible.
Sensorineural hearing loss can result from age or exposure to loud noises that deplete the hair cells in the cochlea. The cochlea simply becomes less sensitive. The result is that a more intense, more energetic sound is needed for the ear to perceive it.
How Do Hearing Aids Help the Hearing Impaired?
You now understand how a conventional hearing aid works and the two types of hearing loss, but how do these devices actually help people with hearing impairment? Here is a detailed examination of their contribution and why they are the most commonly used tool for hearing loss.
Increased Volume
The first, and arguably most obvious, way hearing aids help people with hearing impairment is by increasing the volume of sounds entering the ear. They are placed at the entrance of the ear so that the microphone can pick up sounds that the ear would normally receive and increase their intensity.
When we talk about hearing loss, we usually refer to it in degrees, but this simply measures the softest sound a person can hear. The higher the degree of hearing loss, the louder a sound must be to be perceived.
The sounds a person can hear define their hearing threshold. All a hearing aid does is take sounds outside this threshold and amplify them until they enter it and become audible.
Better Sound Quality
Beyond simple amplification, hearing aids can also help by slightly adjusting the sounds that reach the ear. One of the most difficult situations for people with hearing loss is understanding what is being said in a noisy and chaotic environment.
With purely amplification-based hearing aids, no distinction is made between a speaker's voice and competing noises. People with hearing loss may therefore continue to struggle to understand speech in a chaotic environment.
By slightly adjusting the sound signals picked up by the microphone, some hearing aids offer a clearer sound and make voices stand out from background noise. The CLARIA EV3 and Atom are two examples of hearing aids with enhanced and perfectly clear sound.
Bone Conduction Hearing Aids
Behind-the-ear, in-ear, and invisible models are all forms of hearing aids, but in terms of function, they all rely on the same principle. All include a microphone, an amplifier, and a speaker to aid hearing.
All these hearing aids use air as a medium. But what happens when the person is unable to properly conduct sound waves to the inner ear?
This is where bone conduction hearing aids come in. They look very similar to conventional models, but instead of sending the signal from the amplifier to a speaker, they send it to a component called an oscillator. When an electrical current passes through an oscillator, it vibrates. This is the very principle of bone conduction hearing aids.
The oscillator is either placed on the bone behind the ear using a headband, or attached to a surgical implant inserted into the bone. By transmitting sound vibrations to the bone near the ear, the inner ear can vibrate and perceive sounds.
This system completely bypasses the ear's conduction structures and allows people who would not benefit from a traditional hearing aid to hear better.
Hear Better, More Comfortably
Hearing aids work in a fairly simple way. By converting sound into an electrical signal, amplifying that signal, and then reproducing it through a speaker, they make it easier to hear.
Despite this relatively simple design, many companies charge astronomical sums for a product that should cost a fraction of that price. This is where CLARIA comes in.
CLARIA is a company dedicated to offering high-quality hearing aids at a reasonable price, without breaking the bank. With several models to choose from, you'll find the hearing aid that best suits your life and your budget.
Sources
Conductive Hearing Loss | ASHA
Sensorineural Hearing Loss | ASHA
Inquiring Ears Want to Know: A Fact Sheet About Your Hearing Test | CDC
