Hearing loss or deafness occurs when one or more parts of the ear aren’t working effectively.
How does the ear work:
The ear is the first part of the hearing system. The outside part of the ear (pinna) catches sound waves and directs them down the ear canal. The waves then cause the eardrum to vibrate.
These vibrations are passed across the middle ear by three tiny bones: the malleus, incus and stapes (sometimes known as the hammer, anvil and stirrup, known together as the ossicles). The bones increase the strength of the vibrations before they pass through the oval window into the cochlea.
The cochlea looks like a snail’s shell. It’s filled with fluid and contains thousands of tiny sound-sensitive cells. These cells are known as hair cells. The vibrations entering the cochlea cause the fluid and hair cells to move, much like the movement of seaweed on the seabed when waves pass over it.
As the hair cells move, they create a small electrical charge or signal. The auditory nerve carries these signals to the brain where they are understood as sound.
For an ear to work fully and pick up sound, all of these parts must work well.
(NDCS website, 2020)