How Hearing Aids Work - Breaking It Down
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How Hearing Aids Work – Breaking It Down

Written by Nicholas Dahl - November 28, 2020

How Hearing Aids Work – Breaking It Down

This article has been audited and reviewed by Dr. Ben Thompson, an audiologist and tinnitus expert (bio below).


Thanks to hearing aids, people who suffer from hearing loss and damage are once again able to enjoy things like listening to music, conversing with friends, and other experiences that many take for granted. In 2016, almost four million hearing aids were sold in the United States alone.

These small devices can help rebuild (and in some cases, re-create) one important part of the vibrant and rich experience we call life. But, have you ever wondered how these small miracle creating devices work? In this article we’ll break down how hearing aids work and examine the finer details. Hopefully we’ll give you a newfound sense of respect for these pieces of amazing technology.


What is a Hearing Aid, And What Does It Do? 


Before we jump into how hearing aids work, let’s just ask that basic question. Hearing aids are small electronic devices worn around the ear that amplify sound. They are designed to help those with hearing loss listen, communicate, and engage in normal daily activities that may be impeded by their weakened hearing.

Just like each individual’s hearing loss is different, each person’s hearing aid is also different. Hearing aids are programmed and tuned to match the wearers specific hearing loss, providing the best possible listening experience.


How Hearing Aids Work


Compared to hearing aids of old, current hearing aids have greatly evolved to the current marvel they are now. Although the individual components may be sophisticated, almost all hearing aids can be broken down into three main parts: a microphone, amplifier, and a speaker.

  1. The miniature microphone picks up sound from the environment, converts the sound waves into electric signals, and then sends them to the amplifier.
  2. The amplifier, which consists of a computer chip, boosts the strength of the signal before sending it to the speaker.
  3. The speaker receives this signal and then broadcasts the amplified sound into the user’s ear.

Inside our eardrum we have thousands of small hair cells – these hair cells are what pick up and amplify the sounds we hear, performing the process we call “hearing.”

When these hair cells are damaged they lose the ability to pick up sounds on specific frequencies. Hair cells in the inner ear specifically are unable to regenerate, so damage to them can cause permanent hearing loss and cripple a person’s ability to hear that specific frequency for life. This type of hearing loss is called sensorineural hearing loss

However, with the help of the extra amplification of a hearing aid, those damaged hair cells are once again able to pick up the frequencies, restoring hearing ability. Which sounds and frequencies are amplified is based on the hearing aid settings programmed by an audiologist.


Analog Versus Digital Hearing Aids


While most hearing aids manufactured these days are digital, analog hearing aids are still produced. Usually less expensive than digital hearing aids, analog aids are built and programmed by a manufacturer based on specifications provided by an audiologist about a patient’s hearing. They have less flexibility than a digital hearing aid. However, they usually do have multiple programs or settings designed for different listening environments, such as small crowded rooms or large open halls.

Digital hearing aids, on the other hand, are not usually pre-programmed by the manufacturer. Because they are digital, they convert sound waves in numerical information, much like a computer. This information contains other information, such as volume and pitch. Therefore, a digital hearing aid has quite a bit of flexibility, allowing an audiologist to adjust it specifically for a person’s hearing needs.

Digital hearing aids also contain settings for multiple programs. Some digital hearing aids adjust programs automatically as environments change, and some even include remote controls so users can adjust the settings without having to remove the devices.


The Different Styles of Hearing Aids


While we may have looked at how hearing aids work in general, there are actually many different types of hearing aids! Each allows for the accommodation of a person’s specific hearing needs and their preferences. For a more in-depth look at each type of hearing aid, click the title!


Completely-in-the-Canal (CIC)

This type of hearing aid is the smallest type available. The body of the hearing aid is molded to fit inside the user’s ear canal. Because it sits within the ear canal, it is the least visible hearing aid type. Sitting in the ear canal, it’s much less likely to pick up wind noise than other types. However, because of it’s small size, it uses very small batteries that have a very short life span.

A CIC hearing aid’s small size doesn’t allow for any extra features that may be included on other, larger types. Users of this type of hearing aid are prone to clogs from earwax build-up. CIC hearing aids are designed for people experiencing mild to moderate hearing loss.


In-the-Canal (ITC)

In-the-canal hearing aids are also molded to fit the user’s ear canal and are fitted partially in the ear canal, usually with the microphone exposed in the outer ear. Like a CIC hearing aid, ITC hearing aids are less visible than larger types. An ITC hearing aid usually includes features that you won’t see on a CIC hearing aid, but the controls are often small and unwieldy. ITC hearing aids are designed for people experiencing mild to moderate hearing loss.


In-the-Ear (ITE)

In-the-ear hearing aids come in two styles, a full shell type that fills the area of the user’s outer ear, and half shell type that takes up the lower half of the user’s outer ear. These hearing aids often include many features not found on smaller types; they use a larger battery and thus last longer than smaller hearing aid types. They are, on the other hand, larger and more visible than smaller hearing aid types and thus more susceptible to wind noise. ITE hearing aids are designed for people experiencing mild to severe hearing loss.


Behind-the-Ear (BTE)

This type of hearing aid sits behind your ear via a small hook that goes over the top of the ear. A molded portion sits inside the ear canal and is attached to the outer portion via a tube. This is the largest and therefore most visible hearing aid type (although smaller less-noticeable versions are becoming available). This type of hearing aid is much more powerful than other types; however, it is the most susceptible to wind noises because of its positioning outside of the ear. BTE hearing aids are designed for any degree of hearing loss.


Receiver-in-Canal (RIC) or Receiver-in-the-Ear (RITE)

These types are similar to BTE hearing aids; however, the speaker or receiver is fitted into the ear canal and connected to the outer portion with a tiny wire instead of tubing. Because more of the hearing aid components sit in the ear canal compared to BTE hearing aids, the outer portion of RIC and RITE devices is less visible.


Common & Popular Hearing Aid Features


Hearing aids offer several features that improve the hearing experience for those suffering from hearing loss. Some of these features include:


Directional Microphone

Many hearing aids microphones are referred to as “omnidirectional,” which means that they receive sounds from all directions. Directional microphone hearing aids typically have two microphones that can collect and process sound from multiple directions. The hearing aid can focus on a specific sound source; the sounds picked up by the other microphone are considered background noise and the hearing aid can adjust to decrease the volume of that noise.


Rechargeable Batteries

Many hearing aids on the market today are rechargeable or use rechargeable batteries. This can make a big difference in terms of the cost of having to replace batteries frequently and the ease of being able to simply charge your hearing aids overnight while you sleep.


Wireless Connectivity & Bluetooth Hearing Aids

Most of our devices today, such as cell phones and laptops, include wireless technology; hearing aid manufacturers are also starting to include this technology into their products as well. Bluetooth technology in a hearing aid allows the hearing aid to connect wirelessly with other devices such as cell phones and televisions. This allows the user to answer calls and stream music and other audio straight to their hearing aids, among other useful features.


Do Hearing Aids Really Help?


For the vast majority of people with hearing loss, hearing aids are an effective treatment for hearing loss. For those with severe to profound sensorineural hearing loss in both ears, however, even the assistance of a hearing aid may not be enough. When the hair cells are too damaged, no amount of amplification will help regain hearing. Luckily there are options available aside from hearing aids, such as cochlear implants for severe to profound sensorineural hearing loss or bone anchored hearing aids for conductive or mixed hearing loss.

Aside from restoring hearing, hearing aids also come with a number of health related benefits as well! The effect of hearing loss on health is a topic that has increasingly come under the microscope in recent years, and new findings are showing surprising connections, such as links between hearing loss and depression.

Hopefully we’ve answered your question about how hearing aids work! For more information on hearing aids, hearing health, and all manner of related topics take a look around our blog.


Dr. Ben Thompson

Dr. Ben Thompson is an audiologist and tinnitus expert. Dr. Thompson is the founder of PureTinnitus.com. He decided to specialize in tinnitus management because of his interests in mindfulness, music and psychology. He completed his residency at University of California at San Francisco (UCSF) and is a past board member of the California Academy of Audiology. 

Via telehealth, Dr. Thompson provides tinnitus retraining therapy online. He hosts a YouTube channel, podcast, and tinnitus group coaching program to help individuals with hearing loss and tinnitus.


The information in this guide has been written using the following reliable sources:

Healthy Hearing, Hear usa, Healthyhearing.com/help/hearing-aids, Mayoclinic.org, Hopkinsmedicine.org, Nidcd.nih.gov



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