You know what hearing is, but what is hearing loss? Hearing loss happens when there is a problem with one or more parts of the ear, the nerves coming from the ears, or the hearing part of the brain. People also may use the words deaf, deafness, or hard of hearing when they're talking about hearing loss.

Someone who has hearing loss might be able to hear some sounds or nothing at all. Some kids are born with hearing loss. A hearing problem can also show up later in life.

How Does Hearing Work?

To understand how and why hearing loss happens, it helps to know how the ear works.

The ear is made up of three different parts: the outer ear, the middle ear, and the inner ear. These parts work together so you can hear. The outer ear, or pinna (the part you can see), picks up sound waves that then travel through the 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, part of the inner ear. The cochlea looks like a tiny snail shell. It is filled with liquid and lined with tiny hairs. The sound vibrations make the tiny hairs move. There are two types of hair cells: the outer and inner cells. The outer hair cells take the sound information, make it louder and tune it. The inner hair cells change the sound waves into electrical signals. The hearing nerve then sends the signals to the brain, letting you hear.

What Are the Types of Hearing Loss?

There are a few different types of hearing loss: 

• Conductive (say: kun-DUK-tiv) hearing loss. This happens when something blocks sound from going to the inner ear. Ear infections, ear wax buildup, and problems with the tiny bones of the middle ear are common causes of this type of hearing loss.  
• Sensorineural (say: sen-suh-ree-NUR-ul) hearing loss. This happens when there is a problem in the inner ear or with the connection from the inner ear to the brain. This can happen when the tiny hair cells in the cochlea or the hearing nerve are damaged. 
• Mixed hearing loss. This happens when a person has both conductive and sensorineural hearing loss.
• Central hearing loss. This happens when the inner ear is working properly, but parts of the brain are not. 

What Causes Hearing Loss?

There are many reasons why a person may not be able to hear. Hearing loss can run in some families, or a baby may be born with a problem with how the ear formed. Other causes of hearing loss include:

• serious infections, such as meningitis
• head injury
• listening to very loud music, especially through headphones or ear buds
• being around loud sounds over and over

Ear infections and fluid behind the eardrum can cause hearing loss. When the infection goes away, hearing gets better. 

How Does a Doctor Test for Hearing Loss?

Doctors can do hearing tests at regular checkups or any time there is a concern that a kid does not hear well. The doctor will send a baby or child with hearing loss to an audiologist. An audiologist (say: ah-dee-AHL-uh-jist) is someone who does hearing tests and helps people with hearing loss.

The audiologist checks hearing by doing different types of tests. They even have hearing tests for babies! Maybe you've already had a hearing test? You probably wore headphones and had to raise your left or right hand to show that you could hear in each ear.

How Is Hearing Loss Treated?

The kind of treatment depends on the type of hearing loss, what caused it, and how bad it is. Kids with permanent hearing loss are helped by audiologists; ear, nose, and throat (ENT) doctors; speech-language therapists; and teachers.

Common treatments include 

• medicine, like antibiotics to treat ear infections
• operations, to fix problems in the ear
• hearing aids, to make sounds louder
• assistive listening devices, so kids hear better in the classroom or other noisy places
• cochlear implants for some kids who can’t hear even with hearing aids

A cochlear (say: KO-klee-ur) implant is a tiny device that is put into the cochlea during an operation. It takes over the job of the cochlea and sends electrical signals directly to the hearing nerve. The sounds heard with cochlear implants are different from normal hearing. With therapy and practice, all kids can learn what these sounds mean to better understand speech.

Learning and Communicating

A kid with hearing loss may go to a special school, special classes within a regular school, or be part of a regular classroom. Kids with hearing loss may need hearing and speech therapy.

Some people with hearing loss use special ways to communicate:

• Speech reading (also called lip-reading) involves looking closely at a person's lips, face expressions, and hand movements to help understand spoken words.
• Sign Language is a language of hand movements that lets deaf people communicate without speaking.
• Cued speech is a technique where the speaker makes hand gestures around their mouth. The person watching the speaker uses these hand cues to tell the difference between lip movements that look the same (such as “b” and “p”).
• Signing exact English includes sign language, but its sentence structure and grammar are taken from English.

What about talking on the phone? There are phones that can make voices louder or a conversation can be typed out instead of spoken. The messages appear on a screen.

You might wonder how someone who can’t hear see a movie or watch TV. Closed-captioned TV shows and movies provide text at the bottom of the screen, so people with hearing loss can read along to follow the action.

So kids who don’t hear well can go to school, talk on the phone, and watch a movie. If that sounds a lot like a typical kid's life, you're right!