Hearing loss

Overview

Many parents are concerned about their child's hearing, especially during the early years when infants can't communicate verbally. However, most children don't experience hearing problems. Three out of every 1000 newborns have hearing loss, which is often diagnosed during a routine hearing assessment they're given before leaving the hospital. Hearing loss can also develop later in life for various reasons, and your child's hearing can be evaluated at any age.

Hearing plays a critical role in child development, and even mild or partial hearing loss can affect a child's ability to speak and understand language. Detecting hearing loss early allows parents, teachers and doctors to better assist the child's development and assess corrective options.

Types of hearing loss

There are three main types of hearing loss:

• Sensorineural hearing loss — This type of hearing loss results from a disorder of the inner ear, called the cochlea, or of the auditory nerve that transmits an auditory signal. There are many different causes of sensorineural hearing loss, including congenital (meaning present from birth) infections, medications, genetic factors and overexposure to noise. In half of the cases of hearing loss that's present at birth, called congenital hearing loss, the cause is unknown. Sensorineural hearing loss is usually permanent.
• Conductive hearing loss — This is caused by a disorder affecting the outer or middle ear, such as ear infections with fluid in the middle ear space. Middle ear infections are the second-most common reason children visit a doctor. Generally, when children have middle ear infections with fluid in their ears, they have an accompanying hearing loss. Other common causes of conductive hearing loss include excess wax, foreign bodies in the ear or problems with the three bones in the middle ear. In many cases, conductive hearing loss can be treated either medically or surgically, and may not be permanent.
• Mixed hearing loss — Some children have a combination of both sensorineural and conductive hearing loss.

Signs & symptoms

Review Signs of Normal Hearing to find a list of normal hearing behaviors and key signs to watch for as your child grows. If your baby isn't showing all the developmental signs of normal hearing, that doesn't necessarily mean he or she has a hearing problem, but it does mean an audiological evaluation should be performed.

If you have concerns about your child's responsiveness to sound, discuss your concerns with your pediatrician and request an evaluation by a hearing specialist, called an audiologist. Most importantly, trust your intuition. If you feel that something just "isn't quite right" about your baby's responsiveness to sound, talk to your pediatrician.

Diagnosis

Children are evaluated for hearing loss based on developmental abilities. Various tests are available to assess:

• Whether hearing loss has occurred
• Degree of hearing loss
• Type of hearing loss

The evaluation is tailored to each child to make the test as efficient as possible. The testing may include:

• Behavioral Observation Assessment (BOA) — These tests are conducted on infants by a specially trained audiologist who observes the child's body and head responses to sounds.
• Electrophysioglogic tests — These help determine an infant's hearing levels based on electrical information from the auditory nervous system. They're used when behavioral tests don't provide a complete picture of a child's hearing.
• Visual Reinforcement Audiometry (VRA) — At about 6 to 7 months of age, normally developing children can turn toward a sound source. Children at this level are tested either with earphones or in a sound booth with speakers. This testing is generally quite accurate in determining hearing levels.
• Conditioned Play Audiometry — By approximately 2-and-a-half to 3 years old, most children can be tested using this technique. Earphones are placed on the child and he or she is conditioned to play various games when the test tone is heard.
• Traditional or Standard Audiometry — This testing is used with older children and adults. The method requires the patient to press a response button or raise a hand when the test tone is heard.
• Tympanometry or Acoustic Immittance Testing — This test is used to assess the status of the middle ear and related structures. Tympanometry measures the movement of the ear drum (tympanic membrane). This information is used in the diagnosis of middle ear disease or other problems that might alter ear drum movement.
• Acoustic Reflexes — Measuring acoustic reflexes helps us determine whether the middle ear muscles are properly reacting to loud sounds. This test can also be used in establishing young children's hearing status and or to identify other hearing problems.
• Auditory Brainstem Response Audiometry (ABR), or Brainstem Evoked Response (BSER) — This measures how the brainstem responds to sound. The results can provide general information regarding hearing sensitivity. This test is also used for neuro-diagnostic purposes to determine if the brainstem is transmitting sound properly.
• Otoacoustic Emissions (OAEs) — This test determines cochlear (inner ear) function. Emissions are usually present if hearing is normal or there is only mild hearing loss. Emissions may not be detected if there is a conductive hearing loss, middle ear involvement such as an ear infection, or more than a mild sensorineural hearing loss. This is a quick procedure that doesn't cause any discomfort.

Treatment

A few causes of hearing loss are treatable in infants and children. If a child has a temporary hearing loss due to an ear infection, fluid behind the eardrum or excessive wax in the ear canal, their pediatrician or an otolaryngologist (an ear, nose and throat specialist) can most likely treat the condition successfully. Other cases of hearing loss are caused by problems with the bone structures in the middle ear, and these can sometimes be treated surgically when the child is older, around 7 to 9 years old.

Sensorineural hearing loss, which is typically permanent hearing loss that's caused by a disorder affecting the cochlea or the auditory nerve, usually can't be treated with medication or surgery. However, it can be managed successfully with help from an audiologist and other experts. In addition, it's imperative that doctors fully evaluate children with hearing impairment for other disorders, including visual or kidney defects.

Managing Permanent Hearing Loss

There are many options in managing permanent hearing loss, and your audiologist will provide you with information and resources to help you make the best decisions for your child. Some of these options include:

• Amplification
• Communication options, such as oral language, sign language or a combination of both
• Educational options, such as programs emphasizing listening and speaking, sign language or a combination
• Speech and language therapy

There's no one correct choice when it comes to managing your child's hearing loss. Our pediatric audiologists will help you make choices with all the information possible. It's important to remember that the choices you make for your child may change as your child develops.

Correcting Permanent Hearing Loss

Hearing aids and cochlear implants are two options available for some children, depending on their degree of hearing loss.

In general, children with mild to severe hearing loss are candidates for using hearing aids. Children with severe to profound hearing loss who don't benefit enough from hearing aids may be candidates for a cochlear implant.