12_07_2010 / HEARING LOSS

You know what hearing is, but what is hearing loss? Hearing loss, or hearing impairment (say: im-pare-ment), happens when there is a problem with one or more parts of the ear or ears. Someone who has hearing loss or impairment may be able to hear some sounds or nothing at all. Impairment means something is not working correctly or as well as it should. People also may use the words deaf, deafness, or hard of hearing when they’re talking about hearing loss.

About 3 in 1,000 babies are born with hearing impairment, making it the most common birth defect. A hearing problem can also develop later in life. To understand how and why hearing loss happens, it helps to know how the ear works.

How Hearing Works

The ear is made up of three different sections: the outer ear, the middle ear, and the inner ear. These parts work together so you can hear and process sounds. The outer ear, or pinna (the part you can see), picks up sound waves and the waves then travel through the outer ear canal.

When the sound waves hit the eardrum in the middle ear, the eardrum starts to vibrate. When the eardrum vibrates, it moves three tiny bones in your ear. These bones are called the hammer (or malleus), anvil (or incus), and stirrup (or stapes). They help sound move along on its journey into the inner ear.

The vibrations then travel to the cochlea, which is filled with liquid and lined with cells that have thousands of tiny hairs on their surfaces. There are two types of hair cells: the outer and inner cells. The sound vibrations make the tiny hairs move. The outer hair cells take the sound information, amplify it (make it louder), and tune it. The inner hair cells send the sound information to your hearing nerve, which then sends it to your brain, allowing you to hear.

10_07_2010 / HEARING vs. MONEY