Children and Hearing Loss
Hearing is one of the most important senses – through hearing, children develop language and communication skills, learn to read, appreciate music, marvel at the sounds of our bustling world, and are warned of approaching danger.
Discovering that your child has a hearing loss can come as a shock, but it does not have to put an end to their learning and experiences if it is identified early enough and the appropriate treatment is provided. Often, by acting early and selecting the right technological solutions, sounds – including speech – can still be heard.
What causes hearing loss in children?
Hearing loss can vary greatly among children, and can have many causes. Hearing loss can happen at any time during life – from before birth to adulthood. Babies who are born early, who have low birth weight, or who are exposed to infections in the womb may develop a hearing loss. This can happen to full-term normal-weight babies as well. Genetic factors are the cause of hearing loss in about 50% of cases. Illness, injuries, certain medicines and loud noises can also cause a hearing loss in children (and adults).
Worldwide, about 5 out of every 1 000 children are born with a hearing loss. A further 3 in every 1 000 children will acquire hearing loss in early childhood. The degree of hearing loss can vary from mild (the child doesn’t hear as well as he should) to profound (the child does not hear anything at all).
The importance of early intervention
Hearing loss can affect a child’s ability to develop speech, language, social skills and learning potential. Consequently, the earlier hearing tests are conducted and the hearing loss is identified, the earlier remedial treatment can be started. All children, including newborn babies, can be tested.
Statistics show that if a child with hearing loss is fitted with the appropriate hearing aids before 6 months of age, the child is in a much better position to develop normal speech and language skills, and reach his/her full potential.
(Ref: Yoshinago-Itano, C. (2003). From Screening to Early Identification and Intervention: Discovering Predictors to Successful Outcomes for Children with Significant Hearing Loss. Oxford University Press.)
Signs and symptoms of hearing loss in children
The signs and symptoms of hearing loss are different for each child, but there are some more obvious indicators:
- When a child does not turn his/her head towards a sound, especially a loud sound;
- When a child frequently touches or pulls one or both ears;
- When a child reacts to some but not all sounds;
- When a child turns their head upon seeing you, but not when their name is called from outside their field of vision
- Does my child have difficulty following instructions?
- Does my child ask for instructions to be repeated?
- When a child has delayed speech and language development. If the answer to any of the following is “no”, then your child may have delayed speech and language development:
- Is my child using single words such as “dada” and “mama” by the age of 1?
- Is my child using 2-word sentences by the age of 2?
- Is my child using 3-word sentences by the age of 3?
- Is my child using understandable 4-5 word sentences by the age of 4?
Is my child at risk of a hearing loss?
Below is a checklist that can assist you in determining whether your child might be at risk of a hearing loss. Checking even one of these boxes might mean that your child is at risk – it is advisable to visit your audiologist for a full diagnostic hearing test.
- Our family has a history of children with hearing loss.
- Mothers who had an infection associated with hearing loss during pregnancy, such as German measles.
- My child has spent 5 days or more in the NICU (neonatal intensive care unit), or had complications while in the NICU.
- My child needed a blood transfusion to treat jaundice.
- My child’s head, face or ears are shaped or formed in a different way than usual.
- My child has been diagnosed with a neurological condition that is associated with hearing loss.
- My child has had meningitis (infection around the brain and spinal cord).
- My child has suffered a head injury.
- My child has received certain medications (such as chemotherapy) that may damage hearing (ask your doctor).
- I have reason to be concerned about my child’s hearing.
What to expect when my child comes for a hearing test
A diagnostic hearing test is performed by a paediatric audiologist. The audiologist will perform a series of tests to determine if a hearing loss exists and if so, the type, degree and configuration of the hearing loss.
The following form part of the test battery:
Case history documentation
The audiologist will collect information about family history of hearing loss, conditions that occurred during pregnancy and birth as well as after birth. This information will help the audiologist to determine if there are any risk factors that would indicate that the baby or child is at an increased risk for a progressive or late-onset hearing loss.
A physical examination is done to evaluate the outer ear, ear canal and eardrum.
Tympanometry is done to evaluate the condition of the middle ear system, the mobility of the eardrum and the conduction of sound by the middle ear bones.
Oto-acoustic emissions (OAEs)
The cochlea has outer and inner hair cells. A cochlea that is functioning normally not only receives sound, its outer hair cells also produces low-intensity, measurable sounds called OAEs. The OAE measurement is an objective measurement to determine the integrity and functioning of the outer hair cells.
As a child matures and is able to provide consistent hearing results behaviourally, hearing information can be plotted for each ear specifically. During audiometric testing, the audiologist find the softest level (threshold) at which a child can detect sound at different frequencies (pitches). From this information, a graph of the child’s hearing/hearing loss, called an audiogram, is created.
In infants, visual reinforcement audiometry (VRA) is recommended. After about 2 years of age, a toddler can be trained for conditioned play audiometry.
In the case where an infant/child has a one or more risk factor for hearing loss or has not passed one or more of the above mentioned measurements and/or there is a concern of hearing loss, the following advanced tests will be recommended and performed:
Auditory Brainstem Response (ABR)
ABR testing is an electrophysiological measurement that allows the audiologist to obtain information about the condition of the inner ear and/or auditory nerve. It is a critical procedure as it is an accurate and reliable predictor of hearing loss in infants who are too young to respond to behavioural testing.
Auditory Steady State Response (ASSR)
ASSR testing is another electrophysiological measurement of a baby’s hearing. The ASSR may provide more frequency specific threshold information for infants/children who have severe to profound hearing loss. (Reference: www.infanthearing.org)