What's Hearing Loss?
Whenever Jeff went over to his friend Tony's house, he noticed that his 1-year-old brother Stephen wore what looked like earplugs. When Jeff asked Tony about it, Tony told him that his little brother was hearing impaired and that the hearing aids helped Stephen respond to sounds. Stephen had been born with severe hearing loss and his parents and Tony were learning more about it every day.
To learn more about hearing loss yourself, keep reading.
Info About the Ear
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To understand how and why hearing loss happens, it helps to know how the ear works.
The outer ear, or pinna (the part you can see), picks up sound waves and the waves travel through the outer ear canal. When the sound waves hit the eardrum in the middle ear, the eardrum starts to vibrate. The vibrations pass through three tiny bones called the hammer (or malleus), anvil (or incus), and stirrup (or stapes), and from there the vibrations are sent into the inner ear.
The vibrations travel to the cochlea, a tiny part that is filled with liquid and lined with cells that have thousands of tiny hairs on their surface.
The sound vibrations make the tiny hairs move. The hairs then change the sound vibrations into nerve signals, so your brain can interpret the sound. The signals travel to the brain along special nerves.
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) and it prevents a person from hearing properly.
Impairment is a word that means something is not working correctly or as well as it should. You may also hear the words "deaf," "deafness," or "hard of hearing," when people talk about hearing loss.
Hearing loss may affect one or both ears, and a person may be able to hear some sounds or nothing at all. About two out of 100 babies are born with hearing impairment. Six out of 100 school-age kids develop some kind of hearing loss.
There are a few different types of hearing loss:
· Conductive (say: con-duckt-ihv) hearing loss happens when there is a problem with a part of the outer or middle ear. If the outer ear canal, eardrum, hammer, anvil, stirrup, or other parts of the middle ear aren't doing their jobs correctly, it can cause this kind of hearing loss. Most kids with conductive hearing loss have a mild hearing loss and it is usually temporary because, in most cases, medical treatment can help.
· Sensory (say: sen-sore-ee) hearing loss happens when the cochlea is not working correctly because the tiny hair cells in the cochlea are damaged or destroyed. It can affect one ear or both ears. Depending on the loss, a kid may be able to hear most sounds but they would be muffled (a mild loss), some sounds slightly (a moderate loss), or no sounds at all (a severe to profound loss), and because of this, a kid's ability to talk may be affected. Sensory hearing impairment is almost always permanent.
· Mixed hearing loss is a combination of conductive and sensory hearing loss.
· Neural (say: noor-ull) hearing loss happens when there is a problem with the connection from the cochlea to the brain. If the nerve (neural means related to nerves) that carries the messages from the cochlea to the brain is damaged, there may be a neural hearing loss.
What Causes Hearing Loss?
A kid with conductive hearing loss may have been born with malformed parts of his outer or middle ear. Sometimes a tiny hole in the eardrum or even a buildup of earwax in the ear canal can cause conductive hearing impairment. Ear infections or middle ear fluid are also a common cause of this kind of hearing loss in kids.
Sensory hearing loss can be caused by heredity or genes. Genes are what you inherit from your parents, and they determine everything about you, from your height to your skin color. Sometimes sensory hearing loss happens while an unborn baby is still growing: if a pregnant woman gets certain kinds of diseases, this can cause the developing baby to become hearing impaired.
There are also some serious infections that can cause sensory hearing loss in kids. Some medicines or severe injury to the head can also be a cause. This type of hearing loss can be caused by listening to music that is too loud or being around other loud noise (like the noise at a car race or from firecrackers) a lot, so that should always be avoided.
How Does a Doctor Test for Hearing Loss?
If a doctor thinks that a baby or child may have hearing loss, he or she will recommend that the parents take him to an audiologist. An audiologist (say: aw-dee-oll-oh-jist) is someone who is specially trained to test and help with the problems related to hearing loss.
A pediatric audiologist tests a child's hearing by doing different types of tests. The tests that are used depend on the age of the child. A kid can be tested for hearing loss at any age, beginning at birth.
So how are babies like Tony's brother Stephen tested when they can't even talk yet? Specialized tests are used with newborn babies. By 6 months of age, hearing can be tested in a special soundproof room by observing the behavior of the baby.
The audiologist talks or presents different sounds and watches to see if a baby moves his eyes or turns his head in the direction of the noise. The audiologist may teach a nursery school child to drop a block or play a game when he hears a sound. He or she may also do other tests that use special instruments that measure the child's responses to sounds.
If the audiologist decides that a child has hearing loss, he or she will recommend treatment. The kind of treatment depends on the type of hearing loss, how severe it is, and the child's other needs. The audiologist will also recommend that the parents work with a special team that figures out the best way for a kid with a hearing loss to learn and communicate.
How Is Hearing Loss Treated?
Many kids with conductive hearing loss can be treated with medicine or an operation. Most of these kids will be able to hear normally again.
If a hearing loss is present in both ears, a hearing aid for each ear may be recommended. If hearing loss is present in one ear only, a child may be fitted with either a hearing aid for that ear, or more often fit with an assistive listening device (such as a frequency modulation, or FM, system). FM systems emphasize voices by making them louder and can help kids hear in crowded or noisy classrooms.
Kids with sensory hearing loss and nontreatable conductive hearing loss may need to wear hearing aids. The most commonly fit hearing aid for a child is one which is worn behind the ear. A hearing aid worn in the ear may be suitable for an older child or teenager.
Hearing aids work by using a tiny microphone to pick up sounds, an amplifier to selectively make these sounds louder, and a receiver - very similar to a sound system, only much smaller! The hearing aid delivers the amplified sounds via sound vibrations from the eardrum and middle ear to the inner ear or cochlea. Hearing aid technology is available which can adjust the volume of sounds automatically. An audiologist does special tests to determine which hearing aids will work best for each child.
For some kids who are not able to hear or understand words even with the help of hearing aids, there is a device called a cochlear implant (say: coke-lee-ur imm-plant). This is a very tiny piece of electronic equipment that is put into the cochlea during an operation. It uses electrical signals to stimulate delivery of signals from the cochlea to the hearing nerve. It takes over the job of the damaged or destroyed hair cells in the cochlea by working directly with the hearing nerve.
How Do Kids With Hearing Loss Learn and Communicate?
It depends on the kid! Some kids with greater amounts of hearing loss may attend special schools just for students with hearing loss. Others may attend special classes held at a school for kids who do not have hearing loss. Some schools may have special classes for students with hearing loss, and then the kids who are hard of hearing join up with other kids for a few classes during the day.
Some kids with hearing loss may take regular classes in a school for hearing kids. They sit near the front of the room to hear the teacher better and may use a an FM system in the classroom.
Depending on how severe their hearing loss is, some kids may work with audiologists or speech-language pathologists to help them develop their hearing and speaking skills. Also, kids may learn to speechread, which involves looking closely at a person's lips, facial expressions, and gestures to help figure out spoken words.
Many kids who are severely hearing impaired, learn American Sign Language (ASL). Remember the man next to the singer at the big game? He was using ASL, a language of hand movements that allows deaf people to communicate with one another without speaking. ASL is usually taught and used at residential schools for the deaf.
Kids with severe hearing loss can communicate on the phone by using a special communication device developed for individuals who are deaf or hard of hearing. It is called the TDD, and it allows the conversation to be typed out instead of spoken. The messages appear on a special screen or on a printout.
Closed-captioned TV shows and videos allow a child with hearing loss understand what the hero of the movie is saying or even catch a favorite cartoon alongside kids who can hear. As the people in the movie or the show speak, the words scroll across the bottom of the screen. Many shows on TV are now closed-captioned, so you may have noticed it already.
Kids with hearing loss are not very different from kids who hear normally. In fact, these kids can do pretty much anything that hearing kids can do! The main difference is that they may have to communicate in a special way. Kids who have hearing loss can go on to college, get jobs, have families, and do almost any job they like. In fact, there is even a special university in the United States, known as Galludet University, that is just for students with hearing loss.
When kids with hearing loss grow older, they may get hearing-ear dogs or other special devices that alert them to a problem without depending on sounds.
Updated and reviewed by: Tamara Sides, AuD, CCC-A
Date reviewed: October 2001
Originally reviewed by: Steve Doswhen, MD
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