Most children hear and listen from the moment they are born. They learn to talk by imitating the sounds around them and the voices of their parents and caregivers. But about 2 or 3 out of every 1,000 children in the United States are born deaf or hard-of-hearing. More lose their hearing later during childhood.

Babies should have a hearing screening before they are a month old. If your child has a hearing loss, it is important to consider the use of hearing devices and other communication options by age 6 months. That's because children start learning speech and language long before they talk.

Hearing problems can be temporary or permanent. Sometimes, ear infections, injuries or diseases affect hearing. If your child does not hear well, get help.

Hearing depends on a series of complex steps that change sound waves in the air into electrical signals. Our auditory nerve then carries these signals to the brain.

1. Sound waves enter the outer ear and travel through a narrow passageway called the ear canal, which leads to the eardrum.
2. The eardrum vibrates from the incoming sound waves and sends these vibrations to three tiny bones in the middle ear. These bones are called the malleus, incus, and stapes.
3. The bones in the middle ear amplify, or increase, the sound vibrations and send them to the cochlea, a snail-shaped structure filled with fluid, in the inner ear. An elastic partition runs from the beginning to the end of the cochlea, splitting it into an upper and lower part. This partition is called the basilar membrane because it serves as the base, or ground floor, on which key hearing structures sit.
4. Once the vibrations cause the fluid inside the cochlea to ripple, a traveling wave forms along the basilar membrane. Hair cells—sensory cells sitting on top of the basilar membrane—ride the wave. Hair cells near the wide end of the snail-shaped cochlea detect higher-pitched sounds, such as an infant crying. Those closer to the center detect lower-pitched sounds, such as a large dog barking.
5. As the hair cells move up and down, microscopic hair-like projections (known as stereocilia) that perch on top of the hair cells bump against an overlying structure and bend. Bending causes pore-like channels, which are at the tips of the stereocilia, to open up. When that happens, chemicals rush into the cells, creating an electrical signal.
6. The auditory nerve carries this electrical signal to the brain, which turns it into a sound that we recognize and understand.

Some babies are born with hearing problems. Other children are born with normal hearing and begin to have hearing problems as they grow older.

It’s important to know what to expect as your baby grows, because hearing problems can delay the development of voice, speech, and language skills. The checklist below presents the average age by which most babies accomplish a variety of early speech and language skills. Typically, a child may not accomplish all the items in an age category until he or she reaches the upper age in the age range.

Find your child’s age range in the checklist. Check “yes” or “no” for each item. After you complete the checklist, if any of the items are checked “no,” show it to your child’s doctor. Tell the doctor if you think your child has trouble hearing.

Talk to your doctor

If you think your child may have a hearing problem, here are some things that your doctor might ask you about:

• Do others in the family, including brothers or sisters, have a hearing problem?
• Did the child’s mother have medical problems in pregnancy or delivery (experienced a serious illness or injury or needed drugs or medications)?
• Was the child born early?
• How much did the child weigh at birth?
• Did the child have physical problems at birth?
• Does the child rub or pull on his or her ear(s) often?
• Has the child ever had scarlet fever?
• Has the child ever had meningitis?
• How many ear infections has the child had in the past year?
• How often does the child have colds, allergic symptoms, or ear infections?

Some words the doctor may use are:

• Audiogram: a chart that shows how well you can hear.
• Audiologist: a person who tests and measures hearing.
• Earache: pain deep inside the ear.
• Otitis media: middle ear infection.
• Otolaryngologist: a doctor who treats diseases and problems of the ear, nose, and throat.
• Otologist: a doctor who treats diseases of the ear.
• Pediatrician: a doctor who takes care of infants and children and who treats their diseases.
• Speech-language pathologist: a health professional trained to evaluate and treat people with speech or language disorders.

What are voice, speech, and language?

Voice, speech, and language are the tools we use to communicate with each other.

Voice is the sound we make as air from our lungs is pushed between vocal folds in our larynx, causing them to vibrate.

Speech is talking, which is one way to express language. It involves the precisely coordinated muscle actions of the tongue, lips, jaw, and vocal tract to produce the recognizable sounds that make up language.

Language is a set of shared rules that allow people to express their ideas in a meaningful way. Language may be expressed verbally or by writing, signing, or making other gestures, such as eye blinking or mouth movements.

Your baby’s hearing and communicative development checklist

Birth to 3 Months

• Reacts to loud sounds
• Calms down or smiles when spoken to
• Recognizes your voice and calms down if crying
• When feeding, starts or stops sucking in response to sound
• Coos and makes pleasure sounds
• Has a special way of crying for different needs
• Smiles when he or she sees you

4 to 6 Months

• Follows sounds with his or her eyes
• Responds to changes in the tone of your voice
• Notices toys that make sounds
• Pays attention to music
• Babbles in a speech-like way and uses many different sounds, including sounds that begin with p, b, and m
• Laughs
• Babbles when excited or unhappy
• Makes gurgling sounds when alone or playing with you

7 Months to 1 Year

• Enjoys playing peek-a-boo and pat-a-cake
• Turns and looks in the direction of sounds
• Listens when spoken to
• Understands words for common items such as “cup,” “shoe,” or “juice”
• Responds to requests (“Come here”)
• Babbles using long and short groups of sounds (“tata, upup, bibibi”)
• Babbles to get and keep attention
• Communicates using gestures such as waving or holding up arms
• Imitates different speech sounds
• Has one or two words (“Hi,” “dog,” “Dada,” or “Mama”) by first birthday

1 to 2 Years

• Knows a few parts of the body and can point to them when asked
• Follows simple commands (“Roll the ball”) and understands simple questions (“Where’s your shoe?”)
• Enjoys simple stories, songs, and rhymes
• Points to pictures, when named, in books
• Acquires new words on a regular basis
• Uses some one- or two-word questions (“Where kitty?” or “Go bye-bye?”)
• Puts two words together (“More cookie”)
• Uses many different consonant sounds at the beginning of words

2 to 3 Years

• Has a word for almost everything
• Uses two- or three-word phrases to talk about and ask for things
• Uses k, g, f, t, d, and n sounds
• Speaks in a way that is understood by family members and friends
• Names objects to ask for them or to direct attention to them

3 to 4 Years

• Hears you when you call from another room
• Hears the television or radio at the same sound level as other family members
• Answers simple “Who?” “What?” “Where?” and “Why?” questions
• Talks about activities at daycare, preschool, or friends’ homes
• Uses sentences with four or more words
• Speaks easily without having to repeat syllables or words

4 to 5 Years

• Pays attention to a short story and answers simple questions about it
• Hears and understands most of what is said at home and in school
• Uses sentences that give many details
• Tells stories that stay on topic
• Communicates easily with other children and adults
• Says most sounds correctly except for a few (l, s, r, v, z, ch, sh, and th)
• Uses rhyming words
• Names some letters and numbers
• Uses adult grammar

This checklist is based upon How Does Your Child Hear and Talk?, courtesy of the American Speech–Language–Hearing Association.

A hearing loss can happen when any part of the ear or auditory (hearing) system is not working in the usual way.

Outer Ear
The outer ear is made up of:

• the part we see on the sides of our heads, known as pinna
• the ear canal
• the eardrum, sometimes called the tympanic membrane, which separates the outer and middle ear

Middle Ear
The middle ear is made up of:

• the eardrum
• three small bones called ossicles that send the movement of the eardrum to the inner ear

Inner Ear
The inner ear is made up of:

• the snail shaped organ for hearing known as the cochlea
• the semicircular canals that help with balance
• the nerves that go to the brain

Auditory (ear) Nerve
This nerve sends sound information from the ear to the brain.

Auditory (Hearing) System
The auditory pathway processes sound information as it travels from the ear to the brain so that our brain pathways are part of our hearing.

There are four types of hearing loss:

• Conductive Hearing Loss
  Hearing loss caused by something that stops sounds from getting through the outer or middle ear. This type of hearing loss can often be treated with medicine or surgery.

• Sensorineural Hearing Loss
  Hearing loss that occurs when there is a problem in the way the inner ear or hearing nerve works.

• Mixed Hearing Loss
  Hearing loss that includes both a conductive and a sensorineural hearing loss.

• Auditory Neuropathy Spectrum Disorder
  Hearing loss that occurs when sound enters the ear normally, but because of damage to the inner ear or the hearing nerve, sound isn’t organized in a way that the brain can understand.

The degree of hearing loss can range from mild to profound:

• Mild Hearing Loss
  A person with a mild hearing loss may hear some speech sounds but soft sounds are hard to hear.

• Moderate Hearing Loss
  A person with a moderate hearing loss may hear almost no speech when another person is talking at a normal level.

• Severe Hearing Loss
  A person with severe hearing loss will hear no speech when a person is talking at a normal level and only some loud sounds.

• Profound Hearing Loss
  A person with a profound hearing loss will not hear any speech and only very loud sounds.

Hearing loss can also be described as:

• Unilateral or Bilateral
  Hearing loss is in one ear (unilateral) or both ears (bilateral).

• Pre-lingual or Post-lingual
  Hearing loss happened before a person learned to talk (pre-lingual) or after a person learned to talk (post-lingual).

• Symmetrical or Asymmetrical
  Hearing loss is the same in both ears (symmetrical) or is different in each ear (asymmetrical).

• Progressive or Sudden
  Hearing loss worsens over time (progressive) or happens quickly (sudden).

• Fluctuating or Stable
  Hearing loss gets either better or worse over time (fluctuating) or stays the same over time (stable).

• Congenital or Acquired/Delayed Onset
  Hearing loss is present at birth (congenital) or appears sometime later in life (acquired or delayed onset).

Hearing loss has many causes. 50% to 60% of hearing loss in babies is due to genetic causes. There are also a number of things in the environment that can cause hearing loss. 25% or more of hearing loss in babies is due to “environmental” causes such as maternal infections during pregnancy and complications after birth. Sometimes both genes and environment work together to cause hearing loss. For example, there are some medicines that can cause hearing loss, but only in people who have certain mutations in their genes.

Genes contain the instructions that tell the cells of people’s bodies how to grow and work. For example, the instructions in genes control what color a person’s eyes will be. There are many genes that are involved in hearing. Sometimes, a gene does not form in the expected manner. This is called a mutation. Some mutations run in families and others do not. If more than one person in a family has hearing loss, it is said to be “familial”. That is, it runs in the family.

About 70% of all mutations causing hearing loss are non-syndromic. This means that the person does not have any other symptoms. About 30% of the mutations causing hearing loss are syndromic. This means that the person has other symptoms besides hearing loss. For example, some people with hearing loss are also blind.

The cochlea (the part of the ear that changes sounds in the air into nerve signals to the brain) is a very complex and specialized part of the body that needs many instructions to guide its development and function. These instructions come from genes. Changes in any one of these genes can result in hearing loss. The GJB2 gene is one of the genes that contains the instructions for a protein called connexin 26; this protein plays an important role in the functioning of the cochlea. In some populations about 40% of newborns with a genetic hearing loss who do not have a syndrome, have a mutation in the GJB2 gene.

Hearing Screening

Hearing screening is a test to tell if people might have hearing loss. Hearing screening is easy and not painful. In fact, babies are often asleep while being screened. It takes a very short time — usually only a few minutes.

Babies

• All babies should be screened for hearing loss no later than 1 month of age. It is best if they are screened before leaving the hospital after birth.
• If a baby does not pass a hearing screening, it’s very important to get a full hearing test as soon as possible, but no later than 3 months of age.

Older Babies and Children

• If you think a child might have hearing loss, ask the doctor for a hearing screening as soon as possible.
• Children who are at risk for acquired, progressive, or delayed-onset hearing loss should have at least one hearing test by 2 to 2 1/2 years of age. Hearing loss that gets worse over time is known as acquired or progressive hearing loss. Hearing loss that develops after the baby is born is called delayed-onset hearing loss.
• If a child does not pass a hearing screening, it’s very important to get a full hearing test as soon as possible.

Full Hearing Test

All children who do not pass a hearing screening should have a full hearing test. This test is also called an audiology evaluation. An audiologist, who is an expert trained to test hearing, will do the full hearing test. In addition, the audiologist will also ask questions about birth history, ear infection and hearing loss in the family.

There are many kinds of tests an audiologist can do to find out if a person has a hearing loss, how much of a hearing loss there is, and what type it is. The hearing tests are easy and not painful.

Some of the tests the audiologist might use include:

Auditory Brainstem Response (ABR) Test or Brainstem Auditory Evoked Response (BAER) Test

Auditory Brainstem Response (ABR) or Brainstem Auditory Evoked Response (BAER) is a test that checks the brain’s response to sound. Because this test does not rely on a person’s response behavior, the person being tested can be sound asleep during the test.

ABR focuses only on the function of the inner ear, the acoustic (hearing) nerve, and part of the brain pathways that are associated with hearing. For this test, electrodes are placed on the person’s head (similar to electrodes placed around the heart when an electrocardiogram (EKG) is done), and brain wave activity in response to sound is recorded.

Otoacoustic Emissions (OAE)

Otoacoustic Emissions (OAE) is a test that checks the inner ear response to sound. Because this test does not rely on a person’s response behavior, the person being tested can be sound asleep during the test.

Behavioral Audiometry Evaluation

Behavioral Audiometry Evaluation will test how a person responds to sound overall. Behavioral Audiometry Evaluation tests the function of all parts of the ear. The person being tested must be awake and actively respond to sounds heard during the test.

Infants and toddlers are observed for changes in their behavior such as sucking a pacifier, quieting, or searching for the sound. They are rewarded for the correct response by getting to watch an animated toy (this is called visual reinforcement audiometry). Sometimes older children are given a more play-like activity (this is called conditioned play audiometry).

With the parents’ permission, the audiologist will share the results with the child’s primary care doctor and other experts, such as:

• An ear, nose and throat doctor, also called an otolaryngologist
• An eye doctor, also called an ophthalmologist
• A professional trained in genetics, also called a clinical geneticist or a genetics counselor

Hearing plays an essential role in communication, speech and language development, and learning. Even a small amount of hearing loss can have profound, negative effects on speech, language comprehension, communication, classroom learning, and social development. Studies indicate that without proper intervention, children with mild to moderate hearing loss, on average, do not perform as well in school as children with no hearing loss. This gap in academic achievement widens as students progress through school.

An estimated 12.5% of children and adolescents aged 6–19 years (approximately 5.2 million) and 17% of adults aged 20–69 years (approximately 26 million) have suffered permanent damage to their hearing from excessive exposure to noise.

Hearing loss can result from damage to structures and/or nerve fibers in the inner ear that respond to sound. This type of hearing loss, termed “noise-induced hearing loss,” is usually caused by exposure to excessively loud sounds and cannot be medically or surgically corrected. Noise-induced hearing loss can result from a one-time exposure to a very loud sound, blast, or impulse, or from listening to loud sounds over an extended period.

Preventing Noise-Induced Hearing Loss

Hearing loss caused by exposure to loud sound is preventable. To reduce their risk of noise-induced hearing loss, adults and children can do the following:

• Understand that noise-induced hearing loss can lead to communication difficulties, learning difficulties, pain or ringing in the ears (tinnitus), distorted or muffled hearing, and an inability to hear some environmental sounds and warning signals
• Identify sources of loud sounds (such as gas-powered lawnmowers, snowmobiles, power tools, gunfire, or music) that can contribute to hearing loss and try to reduce exposure
• Adopt behaviors to protect their hearing:
  • Avoid or limit exposure to excessively loud sounds
  • Turn down the volume of music systems
  • Move away from the source of loud sounds when possible
  • Use hearing protection devices when it is not feasible to avoid exposure to loud sounds or reduce them to a safe level
• Seek hearing evaluation by a licensed audiologist or other qualified professional, especially if there is concern about potential hearing loss

People with hearing loss and their families often need special skills to be able to learn language and communicate. These skills can be used together with hearing aids, cochlear implants, and other devices that help people hear. There are several approaches that can help, each emphasizing different language learning skills.

Some families choose a single approach because that’s what works best for them. Other people choose skills from two or more approaches because that’s what works best for them.

Following are language approaches, and the skills that are sometimes included in each of them:

• Auditory-Oral
  Natural Gestures, Listening, Speech (Lip) Reading, Spoken Speech
• Auditory-Verbal
  Listening, Spoken Speech
• Bilingual
  American Sign Language and English
• Cued Speech
  Cueing, Speech (Lip) Reading
• Total Communication
  Conceptually Accurate Signed English (CASE), Signing Exact English (SEE), Finger Spelling, Listening, Manually Coded English (MCE), Natural Gestures, Speech (Lip) Reading, Spoken Speech

Hearing loss can affect a child’s ability to develop speech, language, and social skills. The earlier children with hearing loss start getting services, the more likely they are to reach their full potential. If you think that a child might have hearing loss, ask the child’s doctor for a hearing screening as soon as possible. Don’t wait!

What is Hearing Loss?

A hearing loss can happen when any part of the ear is not working in the usual way. This includes the outer ear, middle ear, inner ear, hearing (acoustic) nerve, and auditory system.

Signs and Symptoms

The signs and symptoms of hearing loss are different for each child. If you think that your child might have hearing loss, ask the child’s doctor for a hearing screening as soon as possible. Don’t wait!

Even if a child has passed a hearing screening before, it is important to look out for the following signs.

Signs in Babies

• Does not startle at loud noises.
• Does not turn to the source of a sound after 6 months of age.
• Does not say single words, such as “dada” or “mama” by 1 year of age.
• Turns head when he or she sees you but not if you only call out his or her name. This sometimes is mistaken for not paying attention or just ignoring, but could be the result of a partial or complete hearing loss.
• Seems to hear some sounds but not others.

Signs in Children

• Speech is delayed.
• Speech is not clear.
• Does not follow directions. This sometimes is mistaken for not paying attention or just ignoring, but could be the result of a partial or complete hearing loss.
• Often says, “Huh?”
• Turns the TV volume up too high.

Babies and children should reach milestones in how they play, learn, communicate and act. A delay in any of these milestones could be a sign of hearing loss or other developmental problem.

Screening and Diagnosis

Hearing screening can tell if a child might have hearing loss. Hearing screening is easy and is not painful. In fact, babies are often asleep while being screened. It takes a very short time — usually only a few minutes.

Babies

All babies should have a hearing screening no later than 1 month of age. Most babies have their hearing screened while still in the hospital. If a baby does not pass a hearing screening, it’s very important to get a full hearing test as soon as possible, but no later than 3 months of age.

Children

Children should have their hearing tested before they enter school or any time there is a concern about the child’s hearing. Children who do not pass the hearing screening need to get a full hearing test as soon as possible.

Treatments and Intervention Services

No single treatment or intervention is the answer for every person or family. Good treatment plans will include close monitoring, follow-ups and any changes needed along the way. There are many different types of communication options for children with hearing loss and for their families. Some of these options include:

• Learning other ways to communicate, such as sign language
• Technology to help with communication, such as hearing aids and cochlear implants
• Medicine and surgery to correct some types of hearing loss
• Family support services

Causes and Risk Factors

Hearing loss can happen any time during life – from before birth to adulthood.

Following are some of the things that can increase the chance that a child will have hearing loss:

• A genetic cause: About 1 out of 2 cases of hearing loss in babies is due to genetic causes. Some babies with a genetic cause for their hearing loss might have family members who also have a hearing loss. About 1 out of 3 babies with genetic hearing loss have a “syndrome.” This means they have other conditions in addition to the hearing loss, such as Down syndrome or Usher syndrome.
• 1 out of 4 cases of hearing loss in babies is due to maternal infections during pregnancy, complications after birth, and head trauma. For example, the child:
  • Was exposed to infection, such as , before birth
  • Spent 5 days or more in a hospital neonatal intensive care unit (NICU) or had complications while in the NICU
  • Needed a special procedure like a blood transfusion to treat bad jaundice
  • Has head, face or ears shaped or formed in a different way than usual
  • Has a condition like a neurological disorder that may be associated with hearing loss
  • Had an infection around the brain and spinal cord called meningitis
  • Received a bad injury to the head that required a hospital stay
• For about 1 out of 4 babies born with hearing loss, the cause is unknown.

Prevention

Following are tips for parents to help prevent hearing loss in their children:

• Have a healthy pregnancy.
• Learn how to during pregnancy.
• Make sure your child gets all the regular childhood vaccines.
• Keep your child away from high noise levels, such as from very loud toys.

Get Help!

• If you think that your child might have hearing loss, ask the child’s doctor for a hearing screening as soon as possible. Don’t wait!
• If your child does not pass a hearing screening, ask the child’s doctor for a full hearing test as soon as possible.
• If your child has hearing loss, talk to the child’s doctor about treatment andintervention services.

Hearing loss can affect a child’s ability to develop speech, language, and social skills. The earlier children with hearing loss start getting services, the more likely they are to reach their full potential. If you are a parent and you suspect your child has hearing loss, trust your instincts and speak with your child’s doctor.