How hearing works

Want to know how hearing works? Learn more about the miraculous process of how we hear.

Have you wondered how hearing works?

Hearing is an intricate, lightning-speed journey of sound through the outer, middle and inner ear. These three parts of the ear each play a vital role in carrying and converting sound waves from the outside environment into electrical signals the brain can understand.

The outer ear consists of the outside part that you can see (the pinna) and the ear canal. The outer ear picks up invisible sound waves from the environment and leads them through the ear canal into the middle ear.

The middle ear consists of the eardrum and three tiny connected bones (ossicles). These individual bones are called the malleus, incus and stapes, but are often referred to as the hammer, anvil and stirrup. When sound enters the middle ear, it hits the eardrum and makes it vibrate. The middle ear bones are set in motion, carrying the sound vibrations through to the inner ear.

The inner ear contains the snail-shaped cochlea and hearing nerve, as well as semicircular canals that help with balance. Vibrations from the eardrum in the middle ear flow through the fluid in the inner ear and cause tiny hair cells in the cochlea to move. The hair cells change this movement into electric impulses that travel to the hearing nerve, which connects to the brain.

The brain then takes these impulses from the hearing nerve, also known as the auditory nerve, and interprets them as sounds.

This entire process enables us to hear and happens in just a fraction of a second.

1. Sound waves enter the ear and travel along the ear canal to the ear drum.

2. Movement of the ear drum makes tiny bones in the middle part of the ear vibrate.

3. These vibrations are transmitted to a fluid filled part of the inner ear, known as the cochlea.

4. Tiny hairs lining the cochlea pick up this movement and send electrical signals to the brain, where they are interpreted as sound.

Hearing loss

Because each of the three parts of the ear are integral to hearing, a problem in any section can cause problems with the way we hear.

Conductive hearing loss is caused by a problem in the outer or middle ear that can result in a temporary or permanent hearing loss.

Sensorineural hearing loss is caused by a problem in the inner ear and/or hearing nerve, usually resulting in a reduced ability to hear and distortion of sounds.

Mixed hearing loss is a combination of a conductive and sensorineural hearing loss.

Central Auditory Processing Disorder (CAPD) is an umbrella term for a variety of conditions that result in a breakdown in the hearing process. In short, the brain cannot make sense of what the ears hear because the auditory signal is distorted in some way. As a result, one of the biggest problems experienced by individuals with CAPD is difficulty listening in background noise.

Learn about the different types of hearing loss

Hearing is different from understanding

Hearing loss doesn’t just affect the loudness at which you can hear sounds, it also reduces the clarity. This can make it harder to understand sounds - such as speech - even when they are loud enough.

If you have sensorineural hearing loss, you will find soft sounds harder to hear than loud sounds. In conductive hearing loss, both soft and loud sounds are affected. Any hearing loss, but particularly sensorineural hearing loss, will distort sounds and make them more difficult to understand.

 

Disclaimer

The information on this website is for educational purposes, and is not intended to replace medical advice. Please consult a hearing healthcare professional to diagnose or treat a hearing or health problem.

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