What is Pediatric Hearing Loss?
Hearing loss in children can be caused by many different health issues. Catching it early and starting treatment as soon as possible is very important. It helps children learn to speak and socialize normally and helps them grow into well-rounded individuals. It can also help us find any reversible causes of hearing loss or other underlying health problems.
When doctors talk about how severe someone’s hearing loss is, they use a scale that measures sound in decibels. The normal hearing range is from 0 to 20 decibels, which is the sound level softer than a whisper. Mild hearing loss means a person can hear sounds that are between 20 to 39 decibels loud, moderate is 40-69 decibels, severe is 70-89 decibels, and profound is over 90 decibels.
There are three primary types of hearing loss: conductive, sensorineural, and mixed. Conductive hearing loss happens when something prevents sound from reaching the inner ear, usually because of a problem with the outer or middle ear. In children, a common cause is ‘glue ear’, a condition where fluid builds up in the middle ear. Sensorineural hearing loss happens when there is a problem with the inner ear or the pathway to the brain that processes sound. Though this type of hearing loss isn’t as common in children, it is the main cause of permanent hearing loss for them. Mixed hearing loss is when a child has both conductive and sensorineural hearing problems.
What Causes Pediatric Hearing Loss?
Hearing loss in children can generally be split into two categories: congenital, meaning they’re born with it, and acquired, meaning they get it later in life.
Congenital hearing loss can be either genetic or non-genetic. Genetic causes, which make up more than half of congenital cases, are due to changes in genes that are either inherited from parents or occur spontaneously. Some genetic causes come with other health issues – these are known as syndromic causes and they account for about 30% of genetic hearing loss. The most common cause of congenital hearing loss is autosomal recessive non-syndromic hearing loss, which is a type of genetic hearing loss that does not come with any other health issues.
Non-genetic causes include certain infections that can happen during pregnancy, known as TORCH organisms (toxoplasmosis, rubella, cytomegalovirus, and herpes). Of these, cytomegalovirus is the most common cause of non-genetic hearing loss in developed countries. Other causes include injury at birth, medications harmful to the ears used during pregnancy, and various risk factors like being born prematurely, having a low birth weight, or having a high level of bilirubin in the blood.
Acquired hearing loss usually develops as a child grows older. The main cause is a condition called otitis media with effusion, which is a build up of fluid in the middle ear that can lead to difficulty hearing. This condition often develops around the ages of 2 and 5, and it generally gets better on its own as the child grows or after a small tube is inserted into the ear to help drain the fluid. Infections are another major cause of acquired hearing loss, especially bacterial meningitis, mumps, and measles. Other causes include issues directly related to the ear like cholesteatoma (a skin growth that occurs in the middle ear), wax build-up, and otosclerosis (abnormal growth in the ears).
Neonates, or newborn babies, have some specific risk factors for hearing loss:
– Specific infections present at birth
– Family history of hearing loss
– Abnormalities in the head and face
– High levels of bilirubin in the blood
– Low birth weight (less than 1500 g)
– Low Apgar score (a health rating for newborns)
– Bacterial meningitis
– Needing prolonged intubation (use of a breathing tube)
Risk Factors and Frequency for Pediatric Hearing Loss
Hearing loss is relatively common, affecting 1 to 3 newborns out of every 1000 births. Furthermore, 1 to 2 out of every 1000 children will suffer from permanent hearing loss. Boys are a bit more likely to experience hearing loss than girls, with the ratio being roughly 1.16 to 1. In the UK, there are approximately 45,000 children with hearing loss, with half of these cases being present at birth.
- Hearing loss affects 1-3 out of every 1000 newborns.
- Out of every 1000 kids, 1-2 will experience permanent hearing loss.
- Boys experience hearing loss a bit more than girls, at a proportion of 1.16 to 1.
- There are about 45,000 children with hearing loss in the UK.
- Half of the cases are congenital, meaning they were present at birth.
Signs and Symptoms of Pediatric Hearing Loss
Hearing loss in children can appear differently based on the child’s age. For newborns, hearing loss is usually identified through newborn screening programs. Older children might show signs of hearing loss such as delayed speech development, behavioral issues, or a habit of turning the TV volume high. It’s important to find out if there are any other symptoms related to the ear, for example, ear discharge, ear pain, ringing in the ears, or dizziness. A complete history of the child is needed, as well as details about any recent trauma, infections, or new medications.
Examining the child’s ear is key in assessing hearing loss. This includes checking the appearance of the outer parts of the ear for any deformities, and using an otoscope to check the ear canal and eardrum, being extra cautious of any signs of cholesteatoma, a condition causing a noncancerous growth in the ear. Depending on the child’s age, the doctor might also check the nerves responsible for facial sensation and muscles, perform a full nervous system examination, and check the child’s balance.
Thanks to the Universal Newborn Hearing Screening program, most cases of hearing loss are found soon after birth, allowing for treatment to begin by the time the child is 6 months old.
Testing for Pediatric Hearing Loss
Assessing a child’s hearing depends on their age and abilities, and different techniques are used for different age groups.
For Newborns:
In the UK, all newborns are offered two types of tests within the first month of their birth:
Otoacoustic Emissions Test: This test measures the vibrations in the tiny hairs of the ear in response to a simple clicking sound. It’s straightforward to perform and doesn’t require any anesthesia. Newborns in the neonatal intensive care unit (NICU) for less than 48 hours also get this test.
Automated Auditory Brainstem Response Test: This test measures the brain’s response to clicking sounds. It’s offered to newborns who have spent over 48 hours in the NICU or newborns who didn’t pass the otoacoustic emissions test twice. Electrodes are placed on the baby’s scalp to measure hearing from the ear up to the brain.
For children aged 6-8 months:
Distraction Techniques: In this method, while an assistant attracts the baby’s attention, the specialist quietly makes sounds from different locations and at different volumes. The child’s reactions to the sounds are assessed to evaluate their hearing.
For children aged 9-36 months:
Visual Reinforcement Audiometry: Children of this age are made to sit with toys at a table situated between speakers that emit sounds. If the child looks toward the sound, a visual reward like a flashing light is given, reinforcing their response.
For children aged 24-60 months:
Conditioned Play Audiometry: Kids are trained to perform a task in response to a sound, like placing a ball in a cup. As the task is learned, the sound level is decreased to find out the lowest volume they can hear.
For children over 60 months:
Pure Tone Audiometry: By the age of five, most children can take a hearing exam called pure tone audiometry, requiring more attention. The test involves presenting sounds of different pitches and volumes and finding out the quietest sound they can consistently detect.
In addition to these tests, further examinations might be needed, depending on the child’s specific condition. For children with a known syndrome, genetic testing might be recommended. Imaging tests like CT scans or MRI scans might also be helpful, as might tests for connexin-26, a specific marker for a type of hearing loss. In some cases, an ECG might be needed to check for a specific syndrome (Jervell Lange Nelsen syndrome) that can cause hearing loss, fainting spells, and sometimes even sudden death.
Treatment Options for Pediatric Hearing Loss
Treatment for hearing loss varies greatly depending on the type of hearing loss you have, what caused it, and your personal preferences or those of your parents.
If you have conductive hearing loss due to an ear infection (otitis media), this is usually treated with antibiotics. Some children may benefit from a surgical procedure called a myringotomy tube, which helps drain fluid from the ear. Sensorineural hearing loss, which happens when the inner ear or hearing nerve isn’t working properly, can’t be treated medically. In milder cases, hearing aids can help, and speech therapy can be useful. However, making sounds louder may cause ear pain and discomfort.
In managing hearing loss, support from family and advice is crucial. There are several ways you can improve your hearing without needing medical equipment or surgery. Techniques include limiting background noise, ensuring people speak to you face-on and with clear pronunciation, and using special devices to help you hear television better. It’s also important that your school gives you the right support. This could mean providing you with special equipment or seating you in a position that helps you hear the teacher better.
There are many types of hearing aids available, each suitable for specific situations. Some, called binaural air conduction hearing aids, rely on the inner ear and hearing nerve working at least partly. These hearing aids pick up sound using a microphone, convert this to a digital signal that can be made louder, then convert it back to sound that is sent to your ear. These hearing aids can be worn behind the ear, in the ear canal, or even further inside the ear.
Other types of hearing aids, known as bone conduction hearing aids, are typically used when there are issues with the ear that make using a regular air conduction hearing aid difficult. This could be due to ear deformities or chronic ear infections. A type of bone conduction hearing aid called a Bone-Anchored Hearing Aid (BAHA) involves surgery to fit a titanium implant fixed into the temporal bone. Sound is then conducted directly to the inner ear through the bone, avoiding the middle ear.
Sometimes, when there’s hearing loss in just one ear, Contralateral Routing of Sound (CROS) hearing aids can be used. These redirect sound from the problematic ear to the better ear without making it louder. If both ears have hearing loss, but one is significantly better, a variation of this hearing aid can be used, called a BiCROS.
Another option for treating hearing loss is a cochlear implant. This involves surgery to place an array of electrodes in the cochlea, the hearing part of the inner ear. These electrodes directly stimulate the hearing nerve, replacing the function of the damaged part of the inner ear. In some countries, this is recommended for children with severe to profound deafness in one or both ears who don’t benefit enough from conventional hearing aids.
Finally, ventilation tubes may be inserted surgically if fluid in the ear is causing hearing loss. Over time, these tubes fall out on their own. If a child has a cholesteatoma, a skin cyst in the ear, surgery will usually be required to remove it.
What else can Pediatric Hearing Loss be?
These conditions could be possible reasons for ear problems:
- Acute otitis media – an infection in your middle ear
- Cholesteatoma – an abnormal skin growth in your middle ear behind your eardrum
- Congenital stenosis – a narrowing present from birth
- Exostoses – abnormal bone growth in the ear canal
- Foreign body – an object stuck in the ear
- Hemotympanum – blood in the middle ear space
- Impacted cerumen – a buildup of earwax
- Keratosis obturans – a rare condition where a hard plug of keratin blocks the ear canal
- Middle ear tumour – a growth in the middle ear
- Otitis externa – an infection in your outer ear canal, often referred to as “swimmer’s ear”
Seeking medical attention is essential for the correct diagnosis and treatment of your ear concerns.
What to expect with Pediatric Hearing Loss
The outcome of hearing loss can greatly depend on its root cause. For instance, if a child is born with sensorineural hearing loss (a type of hearing loss related to damage in the inner ear or nerve pathways) and does not receive treatment, the condition will not likely improve and may even get worse, as seen in cases of congenital CMV (a viral infection that can be present at birth).
On the other hand, a condition known as glue ear – which is often characterized by a build up of fluid in the middle ear – typically has an excellent outcome. In fact, even without any specific treatment, symptoms of glue ear often disappear on their own.
