Hearing loss occurs when ear abnormalities, illness or injury cause a reduction in a child’s ability to detect or process sounds. The loss of hearing that results may be mild, moderate, severe or profound. Problems with hearing are among the most common major abnormalities in babies, according to the American Academy of Pediatrics (AAP).

Hearing loss is either congenital (present at birth or shortly thereafter) or acquired (occurs sometime after birth). It may involve deficits in detecting a range of pitches (high and low sounds), and/or a range of intensities (loud to soft sounds). There are three major types of hearing loss:

• Conductive hearing loss. Occurs when a blockage or structural problem interferes with the process of sound transmission in the outer or middle ear. In most cases, this type of hearing loss is mild and disappears when the underlying condition is treated with medication or surgery.
  
  
• Sensorineural hearing loss. Occurs when the noise signal is transmitted from the outer to the middle ear, but is not properly converted and interpreted by the brain. Malformation, dysfunction or damage to structures in the inner ear, such as the cochlea or hearing nerves, can be causes. In most cases, this type of hearing loss is permanent.
  
  
• Mixed hearing loss. Occurs when hearing loss is a result of both conductive and sensorineural factors.

Hearing loss is most likely to have profound consequences on normal speech and language development when it occurs during infancy and toddler years. Abnormalities in the ear and illness (such as an ear infection) are the most common causes of hearing loss at these ages. Treatment of a child’s hearing condition by 6 months of age is crucial to avoid these deficits. As children enter the adolescent years, injuries and exposure to loud noises become the greatest risk to their hearing.

Hearing loss may come on suddenly, or it may progress slowly over time. The severity of hearing loss varies greatly. Some children may be able to detect certain sounds, but may have trouble hearing others. Other children may have a complete loss of hearing known as deafness.

Hearing loss can be very difficult to diagnose in children who are not yet old enough to speak or to fully express themselves. Hearing problems in babies are most likely to be found during screenings that are routinely performed on children soon after birth. As children grow older, it may become easier to detect signs of hearing loss. Children who appear to have a hearing loss should visit a physician to receive a formal diagnosis.

In many cases, a child’s hearing loss is a temporary symptom resulting from a condition that is highly treatable. However, some forms of hearing loss are more likely to be permanent. In such situations, early treatment with devices such as hearing aids or cochlear implants is crucial to a successful long-term prognosis. Children with hearing loss and their parents can learn American Sign Language to communicate without words.

Most cases of hearing loss – including those caused by a birth defect or illness – are not preventable. However, certain steps can be taken that may reduce the risk of hearing loss.

Hearing loss occurs when something happens to one or more parts of a child’s ear that causes a reduction in the ability to detect or process sounds. The loss of hearing that results may be mild, moderate, severe or profound. At its furthest extreme, hearing loss results in deafness, or total inability to hear sounds.

Problems with hearing are among the most common major abnormalities in infants, according to the American Academy of Pediatrics (AAP). Hearing loss in both ears is present in between one and three out of every 1,000 infants who are born healthy, and in between two and four out of every 100 infants who need intensive care following birth. Hearing impairment is one of the most common forms of birth defects.

People hear through their ears, which help detect sounds in the environment. All sounds have a pitch and intensity (loudness measured in decibels). The process of hearing begins when sounds from the environment travel like waves and are funneled into the outer ear (pinna). The sound travels through the eardrum (the tympanic membrane, which vibrates in response to sound waves) and into the middle ear. There, three small bones (ossicles) – known as the hammer (malleus), anvil (incus) and stirrup (stapes) bones – begin to vibrate, sending the sound signals to the inner ear. A portion of the inner ear called the cochlea is filled with fluid and lined with thousands of tiny hairs. The sound signals move these hairs, which turn the vibrations into electric signals that move along the auditory nerves on their way to the brain.

When something interferes with a child’s ability to process sound, hearing loss may result. In some cases, this damage to a child’s hearing is present at birth. In other cases, a hearing loss does not develop until later in a child’s life.

Hearing loss may involve deficits in detecting a range of pitches (high and low sounds), and/or a range of intensities (loud to soft sounds). Children without hearing impairment can hear sounds in the 0 to 20 decibel hearing level (dBHL) range. Hearing loss is generally diagnosed as belonging to one of the following four categories:

• Mild hearing loss (20 to 40 dBHL). Affects the ability to hear soft sounds. Children who have begun to speak before this type of impairment occurs will likely have normal speech and will be able to engage in conversation relatively easily. Children who have not yet begun to speak at the time of a mild hearing loss may have deficits in speech and language ability that benefit from speech language therapy.
  
  
• Moderate hearing loss (40 to 60 dBHL). Significantly affects the child’s ability to have conversations. Hearing aids and speech therapy can be employed to help children to attend regular schooling and to function well socially.
  
  
• Severe hearing loss (60 to 80 dBHL). Makes normal conversation impossible and significantly impacts a child’s ability to learn spoken language. Children may be able to detect some loud noises and to make out some words, and may benefit from speech and language therapy and hearing aids. Children with severe hearing loss often perform best when attending schools for the deaf.
  
  
• Profound hearing loss (80 or more dBHL). Makes it impossible to hear most sounds, including normal speech. It is extremely difficult for children with profound hearing loss to develop useful spoken language, although children who learn to speak before having a profound hearing loss may be able to retain an understanding of language. Children who have profound hearing loss before learning to speak will not be able to acquire normal language or speech. However, learning sign language will allow them to communicate effectively, and use of a cochlear implant may increase the likelihood that children with profound hearing loss will be able to develop spoken language.

There are three major types of hearing loss:

• Conductive hearing loss. Occurs when a blockage (e.g., ear infection) or structural problem interferes with the process of sound transmission in the outer or middle ear. In most cases, this type of hearing loss is mild and disappears when the underlying condition is treated with medication or surgery. In some cases, a congenital structural abnormality causes conductive hearing loss, which is usually permanent. Conductive hearing loss is the most common type of hearing impairment in children.
  
  
• Sensorineural hearing loss. Occurs when the signal gets through the outer and middle ear, but is not properly converted and interpreted by the brain due to malformation, dysfunction or damage to structures in the inner ear such as the cochlea or hearing nerves. Typically, the tiny hairs in the cochlea that transmit sounds to the brain are damaged or destroyed, causing hearing loss. This type is usually present at birth and may be the result of genetics or a medical problem. The degree of hearing loss can range from mild to profound. It may be evident in just one ear or in both ears, and may get progressively worse over time. In most cases, children with sensorineural hearing loss will not regain a normal level of hearing. However, hearing aids can help children with this type of loss to hear sounds more clearly.
  
  
• Mixed hearing loss. Occurs when hearing loss is a result of both conductive and sensorineural factors.

Hearing loss is most likely to have profound consequences for normal speech and language development when it occurs during infancy and toddler years. Treatment of a child’s hearing condition by 6 months of age is crucial to avoid these deficits.

Hearing loss affects young children in four ways:

• Delays development of speech and language skills
  
• Causes learning problems that may result in reduced academic performance
  
• Leads to social isolation and poor self-esteem
  
• Results in impairment that may affect vocational choices later in life

Even a temporary hearing loss can cause long-term damage to a child’s ability to speak and use language, especially in infancy and early childhood. For this reason, it is crucial that parents have their children’s hearing tested regularly, and that parents watch for signs of hearing loss in their children.

As children grow older, they continue to face potential threats to their hearing. For example, middle ear infections (otitis media) are the primary source of conductive hearing loss in children. They occur when colds and influenza or allergies cause a buildup of fluid in the middle ear that leads to the growth of bacteria. Children may also damage their hearing by inserting objects such as cotton swabs or pencils into the ear and damaging the eardrum.

Hearing loss is either congenital (present at birth or shortly thereafter) or acquired (occurs sometime after birth). In some cases, it is the result of malformation of or damage to a child’s ear that is present at birth. Genetic factors are responsible for about one-half of all cases of hearing loss in children, according to the Centers for Disease Control and Prevention (CDC).

In other cases, an illness or injury damages a child’s hearing sometime after birth. Illnesses that may cause hearing loss include excessive buildup of fluid in the middle ear, infections such as meningitis and ear infections (which usually cause only temporary hearing loss).

Ear infections (e.g., otitis media) are a major source of conductive hearing loss in children. This usually occurs when colds, flu or allergies cause fluid to build up in the inner ear, allowing bacteria to grow. About one in 10 children who have fluid buildup will go on to develop an ear infection. Fluid buildup itself can also cause conductive hearing loss, even if an infection is not present. Other sources of conductive hearing loss in children include blockages of the ear due to insertion of foreign objects or buildup of impacted earwax. Damage to a key part of the ear (e.g., eardrum, ear canal) can result in conductive hearing loss. This type of damage can result from sticking an object in the ear, exposure to a sudden and loud noise, sudden changes in air pressure, a head injury or repeated ear infections.

Most forms of sensorineural hearing loss are present at birth. Damage to the inner ear or auditory nerve causes sensorineural hearing loss. Sources of such damage include:

• Complications during pregnancy or birth. An infection (e.g., toxoplasmosis, cytomegalovirus, rubella) or other illness during pregnancy can contribute to improper development of fetal hearing apparatus, which can cause a hearing impairment. Premature birth and low birth weight can contribute to problems that result in hearing impairment. Problems that occur soon after birth can also cause hearing loss, especially when left untreated. These include lack of oxygen (hypoxia), severe jaundice (kernicterus) and bleeding in the brain.
  
  
• Infections, other illnesses or injuries in the child. Certain sicknesses can damage the structures of the inner ear. Such illnesses include recurrent ear infections, meningitis, mumps, measles, rubella, chickenpox, cytomegalovirus and brain tumors. Head injuries can also cause sensorineural hearing loss.
  
  
• Loud noises. Exposure to a sudden loud noise or loud noise over a period of time can damage the hairs of the cochlea, leading to hearing loss. Excessive volume levels when using electronic devices (e.g., iPods, MP3s, CD players) with earphones for more than five minutes each day can result in permanent damage to hearing, according to a new study.
  
  
• Ototoxic medications. Certain medicines including antibiotics and chemotherapy drugs can have adverse effects on the organs or nerves involved in hearing or balance and lead to hearing loss.
  
  
• Unknown sources. In about half of all cases of sensorineural hearing loss, the cause remains uncertain or unknown.

Certain risk factors make a child more susceptible to hearing loss. For example, many types of hearing loss are the result of genetic factors (e.g, Treacher Collins syndrome). Sensorineural hearing loss is particularly likely to involve genetic factors. Parents of a child with this form of hearing loss are at much higher risk for having additional children with sensorineural hearing loss.

Hearing loss may come on suddenly, or it may progress slowly over time. The severity of hearing loss varies greatly. Some children may be able to detect certain sounds, but may have trouble hearing others. Other children may have a complete loss of hearing known as deafness.

In the majority of cases, impairment occurs in both ears, but it sometimes occurs in just one ear. In addition, the severity of damage may not be the same in each ear.

Parents are urged to watch for certain symptoms that might indicate that a child has hearing loss. For example, infants younger than 6 months old may have hearing loss if they do not startle or turn their heads in reaction to a loud noise, if they are not responsive to a parent’s voice, or if they simply do not turn toward sounds.

Infants older than 6 months may have a hearing problem if they do not turn and react to the sound of their name being called, or if they have a delay in speech or language development. Parents should also be on guard for a potential hearing loss in children who have frequent ear infections or draining of the ears. Other signs of hearing loss in children older than 6 months of age include:

• Academic problems or appearance of daydreaming at school
  
• Balance difficulties, such as trouble holding head steady or walking unsupported
  
• Lack of attentiveness in daycare or at school
  
• Tendency not to follow directions
  
• Tendency to hear some sounds, but not others
  
• Withdrawal from play with other children

Children who are exposed to loud noise for a period of time may experience a ringing or buzzing sound in the ears known as tinnitus. This is a warning sign that noise levels are high enough to potentially damage a child’s hearing.

Hearing loss can be very difficult to diagnose in children who are not old enough to speak or to fully express themselves. Hearing problems in infants are most likely to be found during screenings that are routinely performed by physicians on children soon after birth. Many states require newborns to be screened before leaving the hospital. In other cases, parents may discover that babies do not respond to loud noises or the sound of others’ voices. It is crucial to discover hearing loss as soon as possible – children who are diagnosed and treated by the age of 6 months have the best odds of developing language in a normal manner.

As children grow older, it may become easier to detect signs of hearing loss. Children may report that people seem to mumble a lot and that they often have to ask others to repeat themselves. Parents may also notice that their children do not appear to hear the doorbell or telephone ringing.

Hearing is tested during the regular well-child visits to ensure normal hearing development in children. Parents of children who appear to have hearing loss should consult a physician to receive a formal diagnosis. The physician will perform a complete physical examination and compile a thorough medical history. In particular, the physician will look for signs of fluid, infection, earwax or ear abnormalities. The physician will also look for the presence of a foreign object in the ear.

If underlying illness is ruled out as the source of a hearing loss, the child may be referred to an audiologist, a health professional with expertise in testing the hearing of children and others. In other cases, the child may be sent to an otolaryngologist (ear, nose and throat specialist) who will examine the child’s ears and upper respiratory tract.

There are two major types of hearing tests. Electrophysiologic tests measure a child’s ability to hear based on electrical information generated from the auditory nervous system. Behavioral tests use a technique called audiometry – in which tones are introduced to a child in a soundproof room – while an audiologist observes the child’s responses to these sounds.

In addition to these tests, tympanometry is sometimes performed to measure the eardrum’s response to soft sounds or air pressure in the ear canal.

Most hearing tests are performed in a hospital or other facility with a soundproof room. These tests unfold differently depending on the nature of the test being performed. Once a hearing deficiency has been diagnosed, early treatment is crucial to long-term prognosis.

In many cases, a child’s hearing loss is a temporary symptom resulting from a condition that is highly treatable. Once the underlying condition is successfully treated, the child’s hearing returns to normal. Ear infections (e.g., otitis media) are by far the most common cause of this type of hearing loss in children. This condition will usually resolve on its own without any need for additional treatment. Once an ear infection clears, the child’s hearing problem should also disappear. Children who have recurrent ear infections may have small tubes surgically placed in their eardrums to help prevent fluid from building up. 

Other easily treatable problems are also frequently at the source of a child’s hearing loss. For instance, a buildup of wax can cause a child’s hearing to become muffled. This wax can be easily removed by a physician. Many other disorders can be treated with medications (e.g., oral corticosteroids) or surgery.   

However, some forms of hearing loss are more likely to be permanent. In such situations, early treatment is crucial to a successful long-term prognosis. Children with permanent hearing loss who are treated by the age of 6 months usually develop speech, language, learning and social skills similar to the level of their peers.

In many cases, a child with a hearing deficiency may require a hearing aid. This is an instrument that consists of a microphone, amplifier and receiver that amplifies sounds from the eardrum and middle ear to the inner ear. Hearing aids are available in various styles. Some are placed in or behind the ear, while others are worn on the body. If the hearing loss affects both ears, two hearing aids will likely be suggested.

The major drawback of hearing aids is expense. They can cost several hundred dollars each, and this cost is often not covered by insurance. Families who cannot afford such an expense may be eligible for government assistance to help pay for hearing aids.

Some children benefit from a specialized amplification device known as an FM system. This instrument helps a child to hear well in a noisy environment (e.g., school). Other children may benefit from learning to lip-read or from listening therapy.

Children who have profound hearing loss that cannot be helped by hearing aids may benefit from a cochlear implant. This tiny piece of electronic equipment is placed in the cochlea, where it helps transmit sound past the damaged cochlea directly to the hearing nerves. Children who have cochlear implants are often able to hear things normally and can even use the telephone.

In other cases, children with severe hearing impairment learn to use special techniques to help them communicate better. American Sign Language (ASL) is a system of hand movements that deaf people use to communicate. Hearing people can also learn ASL in order to communicate. Speech reading is another technique that involves learning to examine the movement of lips, facial expressions and gestures to help determine what a person is saying. Special schooling may also be necessary for some children who have hearing loss.

Most cases of hearing loss, including those caused by a birth defect or illness, are not preventable. However, certain steps can be taken that sometimes will reduce the risk of hearing loss. For example, limiting exposure to loud sounds can prevent hearing damage from occurring in children.

Children are urged to keep the volume low on electronic devices, particularly when listening with headphones. The general rule when a child is listening to headphones is that the sound should not be audible to someone standing 3 feet (1 meter) away. Children are also encouraged to wear earplugs when attending loud events such as concerts or when using devices such as lawn mowers.

Hearing loss due to injury can sometimes be prevented by following certain basic steps. For example, children should be taught never to put anything into their ears, especially cotton swabs. Children can also reduce the risk of head injury by wearing seat belts while in the car and wearing protective headgear while playing sports or riding a bike.

Women who are pregnant can take steps to reduce the risk of congenital abnormalities in the fetus that can lead to hearing loss in infants. Women who do not use drugs and alcohol and who protect themselves from infections (e.g., rubella, cytomegalovirus) during pregnancy reduce the risk of exposing their children to factors that may impair development of the ear structure.

Finally, having children immunized against diseases such as measles, mumps, rubella and meningitis (for older children and teens) can virtually eliminate some of the risk factors for developing illnesses that can lead to hearing loss.

Seizure medications may one day be used to help prevent hearing loss due to repeat exposure to loud noises (e.g., explosions), such as in the case of soldiers during war times or other occupations where loud sounds are unavoidable. These agents may help prevent damage to the inner ear’s tiny hair cells (which help sense sound vibrations) and the nerve cells that connect the hair cells to the hearing centers of the brain, according to a recent study. Another study is focusing on stem cell transplantation to help regenerate or repair damaged hair cells and improve hearing. In addition, other research is focusing on developing specialized “micropumps” to administer drugs or other therapies directly to the ears of patients with hearing impairment or loss.

Preparing questions in advance can help patients and parents have more meaningful discussions with physicians regarding their or their child’s treatment options. The following questions related to hearing loss may be helpful:

1. What signs should I look for that might indicate hearing loss in my child?
   
   
2. When will my child receive his or her first hearing screening?
   
   
3. How will you diagnose my child’s hearing loss?
   
   
4. What type of hearing loss do you suspect?
   
   
5. What is the likely cause of my child’s hearing loss?
   
   
6. How severe is my child’s hearing loss?
   
   
7. Is my child’s hearing loss likely to progress?
   
   
8. Is my child’s hearing loss likely temporary or permanent?
   
   
9. What are my child’s treatment options?
   
   
10. What are the risks of these treatments?
    
    
11. How can I help my child prevent hearing loss?