Amplified: A Review on Hearing Aids

Hearing aids are incredible devices that enable individuals who are hard of hearing to be able to recognize sounds around them, allowing them to engage with other people and their surroundings. But how are these tiny devices able to achieve these feats?

The human ear is split into three different sections: outer ear, middle ear, and inner ear. When people hear sounds, the sound waves pass through the outer ear, causing vibrations to occur at the eardrum. These vibrations are then transmitted through the middle ear and into the inner ear. In the inner ear there is a structure called the cochlea. The cochlea possesses thousands of tiny hair particles that are utilized to translate the vibrations from the sound into electrical signals that are transmitted to the brain. Different sounds cause different combinations of hair particles to be affected, transmitting different signals to the brain and allowing humans to distinguish sounds from one another.

Source: Cleveland Clinic

When someone experiences hearing loss, it is often due to damage or loss of the hair cells in the cochlea. These cells can be harmed by factors such as loud noises, genetic predisposition, or the natural aging process. When these hair cells are compromised, they struggle to convert sound vibrations into electrical signals, which impairs their ability to transmit these signals to the brain. As a result, the brain receives distorted or incomplete auditory information, leading to hearing issues.

Hearing aids were invented to help people who had trouble hearing and have revolutionized the technology industry. Unfortunately, hearing aids are unable to restore a person’s hearing capabilities completely because they cannot fix or regenerate new hair particles in the cochlea. Instead, hearing aids amplify incoming sounds and project these amplified sounds straight to the person’s brain.

There are two types of hearing aids: analog and digital. Analog hearing aids use basic technology and operate with fixed settings, providing a more straightforward amplification of sound. On the other hand, digital hearing aids possess more advanced technology that allows them to adapt to various environments and individual hearing needs. This adaptability has made digital hearing aids more in demand, leading to their widespread popularity and availability. As a result, analog hearing aids are now less commonly found on the market.

Source: Amy Sarow/Soundly

Hearing aids have four components that collaborate to amplify any sound: microphone, computer chip, amplifier, speaker. The first component is the microphone, a small device that picks up sound waves that come into contact with it. There are three main types of microphones that work best in certain surrounding environments. Omnidirectional hearing aid microphones capture sounds from every direction. Because it picks up all sounds, omnidirectional microphones are best suited from quiet environments. This way, the microphone is able to provide a natural and balanced auditory experience for the wearer. Directional hearing aid microphones focus on sounds coming from specific directions. Because of this, directional microphones are best suited for noisy and busy environments where there are many people talking at once. By concentrating on sounds from a particular source, these microphones not only amplify certain sounds but also minimize background noise. This helps wearers hear specific sounds more clearly in the midst of multiple competing sounds. Adaptive directional hearing aid microphones capture sounds depending on the level of noise within an environment. Because it can automatically adjust the direction of sound intake, it is able to perform the same features as directional microphones in every direction it needs. This type of microphone is suited for any type of setting, making it a popular choice for hearing aids. After picking up sounds, the microphone then converts the sound waves into electrical signals that are passed to the amplifier. 

The amplifier is a device that makes incoming sound louder. It receives the electrical signals from the microphone and boosts their strength so that the sound is increased in volume. The amplified sounds are then sent to the speaker. The speaker, also known as the receiver, is a device that broadcasts sound into the ear. After receiving the amplified electrical signals from the amplifier, the speaker converts the signals back to sound waves before sending them to the human ear.

A feature that only appears in digital hearing aids are computer chips. These computer chips perform their work between the microphone and the amplifier. It receives the electrical signal information from the microphones and then analyzes it to instruct how much the signals should be amplified by the amplifier. It uses special algorithms to achieve this and basically tailors the sounds the wearer hears to the wearer’s hearing needs. This special piece of equipment is what widens the gap between digital and analog hearing aids.

Although they may not replenish a person’s hearing capabilities completely, hearing aids offer those who suffer from hearing loss a chance to start well connected with the sounds around them. This allows them to engage with the environment more and interact more with those around them. I hope you learned something new! Keep a lookout for the next post!

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References

Audibel. (2023 Feb. 23). How Do Hearing Aids Work?. Audibel. Retrieved October 23, 2023, from https://www.audibel.com/hearing-technology/how-hearing-aids-work/

Cleveland Clinic. (2023 Feb. 21). Hearing Aids. Cleveland Clinic. Retrieved October 23, 2023, from https://my.clevelandclinic.org/health/treatments/24756-hearing-aids

Torborg, L. (2016 Dec. 17). Mayo Clinic Q and A: Hearing loss and how hearing aids may help. Mayo Clinic. Retrieved October 23, 2023, from https://newsnetwork.mayoclinic.org/discussion/mayo-clinic-q-and-a-hearing-loss-and-how-hearing-aids-may-help/