FAQ - Discover your child's hearing

Hearing and hearing loss

Will my child ever hear me?

This depends on the degree of hearing loss. Nowadays, there are very few hearing losses that cannot be helped with modern technology. Children with hearing loss, given the right support and technology, are often able to hear speech as well as many of the other sounds of our bustling world.

Will my child ever talk to me?

Speech ability depends on the level of your child’s hearing. Many children with hearing loss develop good speech and language when given the appropriate support. The important thing is early identification of the hearing loss and appropriate intervention measures. Your child should be exposed to speech as soon as possible.

Can hearing impaired children develop speech and language?

The overwhelming answer is yes! With the right amplification and support, hearing impaired children can learn to babble, talk, make friends, go to school/university and do almost anything that a hearing person can do. There are often challenges on the way, but the future can be bright for many hearing impaired children in today’s world.

How many children are affected worldwide by hearing loss?

Hearing loss in children is much more common than you think. There are 170 million hearing impaired children worldwide who will need a life time of support (WHO, 2002). Hearing loss affects 1-3 infants per 1000 births and is the most common congenital sensory disorder. This number increases when we include conductive hearing losses such as those caused by middle ear fluid.

What should I do if I am worried about my child’s hearing?

If you have any concerns about your child’s hearing, even if your child has already had a hearing test in the past, it is important to seek help as soon as possible. Go to your family doctor and ask to be referred to a specialist centre (such as your local Ear, Nose and Throat clinic) so that your child’s hearing can be assessed. Remember that the outcomes for many children with hearing loss are better than they have ever been before.

How does the ear work?

The ear has three main parts: the outer, middle and inner ear. The outer ear (the part you can see) opens into the ear canal. The eardrum separates the ear canal from the middle ear. Small bones in the middle ear help transfer sound to the inner ear. The inner ear contains the auditory (hearing) nerve, which leads to the brain. Any source of sound sends vibrations or sound waves into the air. These funnel through the ear opening, down the ear, canal, and strike your eardrum, causing it to vibrate. The vibrations are passed to the small bones of the middle ear, which transmit them to the cochlea and the hearing nerve in the inner ear. Here, the vibrations become nerve impulses and go directly to the brain, which interprets the impulses as sound (music, voice, a car horn, etc.). The brain is the most important part of the hearing mechanism.

Where does hearing loss occur in the ear?

Hearing loss can occur in the outer ear, middle ear, inner ear or brain. Where the hearing loss occurs is typically determined by the results of different hearing tests. Laboratory and x-ray procedures may also be used to help determine where in the ear the hearing loss occurs.

How is hearing loss measured?

Sound occurs at different pitches called “frequency” and at different loudness levels called “intensity”. The measurement unit for frequency is Hertz (Hz) and the measurement unit for intensity is the decibel (dB). The range of pitches that we hear includes low (250 Hz) and high frequencies (8000 Hz). The ranges of intensities that we hear are 0 dB (very soft sound) to 120 dB (very loud sound). A hearing test is a measure of how soft we hear at each pitch or frequency.

What is an audiogram?

An audiogram is a graph that shows the softest level that we hear at each frequency from 250 Hz to 8000 Hz. Hearing is considered normal at each frequency if it falls above 20 dB on the audiogram. A hearing loss is present at a certain pitch or frequency range if the softest level that we hear falls below 20 dB on the audiogram.

What are the ‘speech frequencies’ and why are they important?

Speech sounds occur at different frequencies. Most of the vowel sounds occur in the lower frequencies and most of the consonants occur in the higher frequencies. In general, vowel sounds are louder than consonants. If hearing loss occurs in the high frequencies it is more difficult or impossible to hear the consonant sounds. The range of frequencies typically referred to as the speech frequencies are 500 to 4000 Hz. The speech frequencies are important because we have to be able to hear speech in order to learn speech and language. If a hearing loss occurs in this range, it interferes with the ability to hear speech, develop speech and language, and to communicate.

What is degree of hearing loss?

The degree of hearing loss refers to the severity of hearing loss. For children, hearing is usually described by the average hearing level.

  • Normal range or no loss: 10 to 15 dB
  • Slight Loss/Minimal Loss: 16 to 25 dB
  • Mild Loss: 26 to 30 dB
  • Moderate Loss: 31 to 50 dB
  • Moderate/Severe Loss: 51 to 70 dB
  • Severe Loss: 71 to 90 dB
  • Profound Loss: 91 dB or more

Please note that for hearing tests, particularly those with younger children, it is very common that a hearing care professional may not test below 30dB. This is due to the difficulty in testing younger children and because children often do not respond to the quietest sounds they hear during a hearing test. This test is referred to as a hearing screen and it rules out any significant hearing loss.

What are common symptoms of hearing loss in infants?

Your baby may have some degree of hearing loss if he/she shows the following behaviors:

  • Does not startle, move, cry or react in any way to unexpected loud noises.
  • Does not awaken to loud noises.
  • Does not turn his/her head in the direction of your voice, or
  • Does not freely imitate sound.

What are common symptoms of hearing loss in toddlers?

Your child may have some degree of hearing loss if he/she shows the following behaviors:

  • Inconsistent responses to sound
  • Delayed language and speech development
  • Unclear speech
  • Turns up sound on TV, radio and cd player
  • Does not follow directions
  • Often says “Huh?”
  • Does not respond when called

Genetic causes of hearing loss

What is genetic hearing loss?

The part of the body that controls the unique characteristics of a person is a gene. Genes determine eye and hair color. A genetic hearing loss is caused by information carried by the genes. There are many different types of genetic hearing loss.

What are the different types of genetic hearing loss?

There are two types of genetic hearing loss. About sixty-six percent of genetic hearing losses are not related to syndromes. Thirty four percent are related to syndromes. A nonsyndromic hearing loss means that the hearing loss occurs without involvement of other systems in the body. A syndromic hearing loss means that the hearing loss occurs in combination with a recognized set of characteristics.

What are the characteristics of nonsyndromic hearing loss?

Nonsyndromic hearing loss is an inherited pattern of hearing loss that occurs at birth or in early childhood. The most common type of nonsyndromic genetic hearing loss is called Connexin 26 and is tested by a blood test. There are many other hearing loss genes that are not as easy to test for.

What is a syndrome?

A syndrome is a recognized set of characteristics that occur together. Syndromes are often named after the person that first described it.

What are the characteristics of syndromic hearing loss?

The characteristics of the hearing loss depend on the syndrome. Some syndromes are associated with conductive hearing loss. Other syndromes are associated with sensorineural or mixed hearing loss. The degree of hearing loss also depends on the type of syndrome. More importantly, syndromes are a set of characteristics that affect other parts of the body. Other parts of the body that are often affected are the eyes, face, head, heart, bones, and kidneys.

Are there other types of genetic hearing loss?

Sometimes there is no reason to suspect a hearing loss; the ear is just not shaped properly. The outside part of the ear can be absent or misshapen. The ear canal can be misshapen or closed. The inner ear consisting of the cochlea might be misshapen or malformed. The baby could be born with a small or absent hearing nerve. It is not always possible to determine whether these ear anomalies are genetic or not. In the future, there may be tests developed that can help provide this information.

Diseases that can cause hearing loss

What are some of the diseases that could contribute to a hearing loss for the newborn?

Some of the more common diseases associated with hearing loss include cytomegalovirus, herpes simplex, rubella, syphilis, toxoplasmosis, and varicella.

What is cytomegalovirus (CMV)?

CMV is a very common virus. About three percent of babies are born with this virus. Many babies do not have any symptoms. A small percentage of the babies born with CMV have symptoms. Of the babies that have symptoms, about fifty percent are born with hearing loss or develop hearing loss.

What is herpes simplex?

Herpes simplex is a virus that is passed from the mother to baby during birth. Many of the babies born with herpes develop a combination of neurological problems and hearing loss.

What is rubella?

Rubella is a type of measles. If a mother has rubella during the first trimester, it can cause heart problems, eye problems and hearing loss. Rubella was a common cause of hearing loss before a vaccine became available. Rubella is now a relatively rare cause of hearing loss.

What is varicella?

Varicella is also called chicken pox. Varicella is transmitted to the baby during the first two trimesters of pregnancy. Characteristics of varicella include hearing, skin, eye, bone, and neurological problems.

What is syphilis?

Syphilis is a bacterial disease transmitted to the baby during pregnancy. Babies born with syphilis may have teeth, bone, eye, and neurologic problems in addition to hearing loss.

What is toxoplasmosis?

Toxoplasmosis is a parasite infection. It is transmitted from mother to baby during pregnancy. The parasite affects the brain, eye, and ears. Babies born with toxoplasmosis frequently have no symptoms at birth. Hearing loss develops in about ten percent of infected babies.

What is meningitis?

Meningitis is a disease that is contracted after birth. It is an infection or inflammation of the meningis or lining of the brain. It can be caused by bacteria or by a virus and may result in sensorineural hearing loss. Availability of a vaccine has decreased some types of meningitis.

Side Effects of Treatment that can cause hearing loss

What are some of the medications used to treat sick babies that can cause hearing loss?

Some antibiotics that can cause hearing loss include gentamycin, tobromycin, kanamycin and streptomycin. Medications like dopamine or furosemide used to treat lack of oxygen have also been linked to hearing loss. Other medications that can cause hearing loss are used as treatment for cancer, like cisplatinum. If your baby is very sick and is in the neonatal intensive care unit ask the doctor to keep you informed about the medications and potential side effects of treatment.

What are some other treatments that can cause hearing loss?

Jaundice is a yellowing of the skin related to elevated bilirubin levels. This condition is called hyperbilirubinemia. The treatment for hyperbilirubinemia includes light treatment and may include an exchange transfusion. About twenty percent of babies requiring exchange transfusion develop hearing loss.

Why are premature infants at risk for hearing loss?

Premature infants and infants with extremely low birthweight sometimes have difficulty breathing normally. This is called persistent pulmonary hypertension (PPHN). The treatment for PPHN may be intubation, ventilation, or oxygen treatment. Hearing loss has been associated with these treatments. Babies with PPHN that are very, very sick may require a treatment called extracorporeal membrane oxygenation (ECMO). Up to fifty percent of babies that survive treatment may develop hearing loss. The hearing loss often develops after hospital discharge. It is important that these babies receive regular hearing evaluations until they are at least three years of age.

Environmental Factors that can cause hearing loss

What is fetal alcohol syndrome?

Fetal exposure to alcohol during pregnancy can cause conductive or sensorineural hearing loss. Other features include slow growth development, misshapen facial features, and behavior disorders.

What are ototoxic medications and what effect might it have on a baby’s hearing?

Medication taken by a mother during pregnancy can cause hearing loss. Trimethadione is used to treat seizures and can cause hearing loss if taken by the mother during pregnancy. Other medications known to cause sensorineural hearing loss include acetylsalicylic acid, aminoglycosides, neomycin, nortriptyline, quinine, streptomycin, thalidomide, vancomycin, and viomycin.

What is lead poisoning?

Lead poisoning is caused from exposure to paint that is lead based. This type of paint used to be commonly used and may still exist in some older homes. Babies who eat lead paint chips can get lead poisoning. Lead poisoning causes brain damage and hearing loss.

What is trauma?

Trauma is damage or injury that accidentally occurs. Infant hearing loss can be caused from head trauma, or other types of ear injuries.

What kind of head trauma might result in a hearing loss?

Babies born with an enlarged vestibular aqueduct are highly susceptible to head trauma. For these babies, minor head trauma can induce or increase a permanent hearing loss. Head trauma can cause the bones in the middle ear to be broken apart. Severe head trauma can result in a fracture of the temporal bone causing hearing loss.

Acknowledgements

Phonak acknowledges the permission and assistance of the following organizations for their expertise in this portion of our website:

Real People.
Real Stories.