How hearing aids work
At a certain age, normally later in life, sounds and speech can start to become muffled.
Words can get drowned out by background noise, and it can become a common habit to ask coworkers or family members to speak louder.
Suddenly, watching TV can only be done on the highest volume, bothering others at home.
Around a third of people in the US aged 65 to 75 years old, and half over 75 years old, report some degree of hearing loss.
However, hearing loss isn’t limited to the elderly. Hearing loss can affect various aspects of one’s life, which is why many who suffer from it turn to hearing aids.
What is hearing loss?
There are three types of hearing loss: conductive, sensorineural, and mixed.
Conductive hearing loss involves the outer or middle ear, sensorineural hearing loss involves the inner ear, and mixed hearing loss involves both.
When the ear is fully functional, sound waves travel through the outer ear, causing vibrations at the eardrum, where the vibrations are amplified as they go towards the inner ear.
In the inner ear, the vibrations pass through the cochlea, where there are nerve cells and tiny hairs that transform the vibrations into electrical signals that the brain can turn into sound.
If earwax has built up inside a person’s ear canal, this can cause hearing loss, and solely having the earwax removed can potentially solve the hearing loss.
More serious causes of hearing loss include damage to the inner ear, an ear infection, a ruptured eardrum, or abnormal bone growths or tumors.
Although inner ear structures degenerate over time, certain medications and illnesses and exposure to loud noise can also make a person prone to hearing loss.
What is a hearing aid?
A hearing aid is a small electronic device that one can wear on their ear to make sounds louder.
Hearing aids can help a person hear better in both quiet and noisy settings, and in turn, allow one to participate in conversation more actively.
The three basic parts of a hearing aid are the microphone, amplifier, and speaker.
The microphone receives sound waves and converts them into electrical signals, which are then sent to the amplifier.
The amplifier increases the strength of the signals it receives and sends them to the speaker, which amplifies them into the ear.
Because it is an electronic device, a hearing aid must have a power source, commonly small, specialized batteries.
Hearing aids are especially helpful for people who have suffered sensorineural hearing loss, usually due to aging, disease, injury, or medicine.
The hair cells in the inner ear are able to detect the vibrations magnified by the hearing aid, allowing the brain to detect neural signals.
The hearing aid may need to be adjusted for amplification depending on the severity of damage to the hair cells.
Unfortunately, a hearing aid would be ineffective on a severely damaged inner ear or for someone who is deaf from birth.
To find out if one could benefit from a hearing aid, an otolaryngologist (ear, nose, and throat doctor) will first assess the cause of the hearing loss while an audiologist (hearing health professional) measures the degree of loss that a person is experiencing.
How does a hearing aid work?
Not all hearing aids work the same way.
There are two main types of electronics used for hearing aids: analog and digital.
Analog hearing aids, the less expensive option, convert sound waves into electrical signals and amplify them based on the settings specified by an audiologist.
An analog hearing aid can be programmed by the manufacturer based on these specifications and can also be changed by the audiologist for use in different listening environments.
They normally have simple volume controls.
Instead of converting sound waves into electrical signals, digital hearing aids convert them into numerical codes similar to computer binary codes then amplify them.
The numerical codes contain information about each sound’s pitch, volume, and direction, allowing the digital hearing aid to amplify some frequencies more than others. An audiologist can easily adjust the aid to suit the user’s listening environments, but most digital hearing aids adjust automatically.
They are usually more expensive than analog hearing aids, but they are smaller and offer better results.
How do hearing aid styles differ?
The three main styles of hearing aids are canal, in-the-ear (ITE), and behind-the-ear (BTE) hearing aids.
Canal hearing aids include in-the-canal (ITC), completely-in-canal (CIC), and invisible-in-canal (IIC) models, all of which are more difficult to see because they fit inside the ear.
An ITC hearing aid is custom molded to the user’s ear canal and fits partly in the ear.
Though it is less visible than larger hearing aids, its speaker can get clogged with earwax.
A CIC hearing aid can help mild to moderately severe hearing loss. It may be smaller than an ITC, but it normally has a shorter life because it uses small batteries that may not often be replaced since this type of hearing aid is more difficult to remove from the ear.
An IIC hearing aid is placed deep in the ear canal, making it almost undetectable to others. It is also suitable for extended wear.
ITE hearing aids can be custom made to fill either most or only the lower part of the outer ear.
Because they are larger than other hearing aids, they allow for volume control and have longer battery life.
However, they might detect more wind noise and are not always suitable for children whose ears may still be growing.
BTE hearing aids rest behind the ear with a tube connecting to the ear canal.
Aside from new miniature styles, BTE hearing aids are usually the largest type.
These can detect more wind noise than the other types, but are not prone to earwax clogging and are suitable for any degree of hearing loss.
Adjusting to one’s hearing aid
It’s important to acknowledge that a person’s hearing aid will not take the person’s hearing back to normal.
The person should try to get used to the hearing aid once it is received, and not be discouraged if it doesn’t seem to work for them.
It is encouraged for individuals to speak with their doctor about any concerns they may have with their hearing aid.
With lots of care and barring any major hearing changes, hearing aids may last for many years.
