Overview of Hearing Aid Fitting for Children
Worldwide, we now have programs in place that allow us to identify hearing loss in newborn babies within their first few weeks of life. It’s also possible to quickly diagnose children who develop hearing loss later on, or have temporary hearing loss due to genetic reasons, an infection in their middle ear (also known as ‘glue ear’), a virus called cytomegalovirus, certain medications that can harm hearing, or injuries.
Without the ability to hear properly, kids might struggle to develop their speech and language skills. They could also have issues with learning new things by chance and socializing. This can unfortunately impact their self-confidence, how they do at school, and what opportunities they have in the future. However, when used and adjusted correctly, hearing aids can help children with hearing loss to overcome these challenges compared to kids with normal hearing.
A hearing aid is a battery-powered device that increases the volume of sounds. It does this by picking up sounds from the surroundings and making them louder according to the wearer’s specific hearing needs, before transmitting these sounds into the wearer’s outer ear. Basically, a hearing aid is made up of a microphone, an amplifier, and a speaker. It specifically targets the hair cells inside a part of the inner ear called the cochlea, which work to pick up sound.
Hearing aids have two main ways of transmitting sound:
- Air conduction: These are the common types of hearing aids that transfer sound via the hearing pathway, which includes the outer, middle, and inner ears. You can either wear this type of hearing aid behind the ear or inside the ear.
- Bone conduction: If the outer and/or middle ears aren’t working right, these devices transfer the sound through the bone of the skull directly into the inner ear, skipping the other ear parts. They are generally worn on a hard or soft headband. These shouldn’t be mistaken for bone-anchored hearing aids, which are a different type that get surgically implanted into a bone at the back of the ear, even though they rely on the same transmission method.
Presently, almost all hearing aids available for purchase are digital. This makes it possible for healthcare professionals to adjust the settings on each hearing aid to match the specific needs of each user. This means they can be adjusted for different environments, like a noisy classroom, can connect with devices like mobile phones and tablets, and can track how long they’ve been used.
If a hearing aid is fitted correctly by an experienced healthcare professional, it can provide children with hearing loss better access to the speech and sounds in their environment. This can help them develop just as well as their peers who can hear normally.
Anatomy and Physiology of Hearing Aid Fitting for Children
The human ear is divided into three main parts: the outer ear, the middle ear, and the inner ear.
The outer ear is made up of the pinna (the part of the ear we usually see on the outside of our heads) and the ear canal. The role of the outer ear is to catch sound waves from our environment. Sound is then directed through the ear canal to the eardrum.
The middle ear consists of the eardrum and three tiny bones: the malleus, incus, and stapes. The middle ear is filled with air and its job is to balance the air pressure inside the ear with that of the atmosphere outside. The Eustachian tube, which connects the ear to the back of our throat, helps to maintain this balance. When the sound reaches the eardrum from the outer ear, it causes the eardrum, and thus those tiny bones, to vibrate. The last of these bones, the stapes, is linked to a structure in the inner ear known as the oval window.
The inner ear is home to the cochlea and the semicircular canals. The cochlea looks a bit like a snail shell and it has a system of fluid-filled passages. Within the cochlea, there is a special structure known as the Organ of Corti, which contains many tiny ‘hair cells’. These cells are sensitive to different sound frequencies. When the stapes vibrates at the oval window, it stirs up the fluid in the cochlea. This motion activates the hair cells, which then send electrical signals to the brain, allowing us to ‘hear’. The semicircular canals help our brain understand our head movements and speed.
Normally, sound is transmitted through the air from our outer ear to our inner ear – this is known as air conduction. However, sound can also be conducted through the bones of our skull directly to the inner ear. This is known as bone conduction. Each ear’s bone and air conduction pathways help determine the best type of hearing aid for individuals whose hearing is impaired. For instance, if the outer or middle ear cannot work properly, a hearing aid that uses bone conduction might work better.
Why do People Need Hearing Aid Fitting for Children
If a child under 18 years of age is found to have hearing loss that could potentially improve with the use of a hearing aid, doctors would usually recommend one. Here are some factors that doctors look at when deciding if a child needs a hearing aid:
1. How much hearing loss the child has: How well a hearing aid works can be influenced by what parts of a child’s ear aren’t working properly. If a child has severe hearing damage because of poor cell function in the inner ear (also known as the cochlea), a hearing aid might not help. This is because the hearing aid might not be able to make sounds loud enough to be understood in normal conversation. In these cases, a device called a cochlear implant that gently stimulates the inner ear might be more helpful.
Unfortunately, doctors don’t completely agree on if very mild, single-sided, or specific cases of hearing loss can benefit from a hearing aid. There’s just not enough information to show whether these devices can help with delays in speech and language. Because of this, doctors usually decide if these children need hearing aids on a case-by-case basis.
2. The kind of hearing loss the child has: If a child has temporary and changing hearing loss because of a problem called “glue ear”, a type of hearing aid that sends sounds through the bones of the ear (a bone conduction hearing aid) might be better. This could prevent the hearing aid from making sounds too loud and lessen the need for constant adjustments.
3. The shape of the child’s ear: The effectiveness of the hearing aid can be impacted if a child’s outer or middle ear is shaped differently. For kids with these types of ears, hearing aids that work through bone conduction may offer better outcomes. When a child’s outer ear (pinna) is shaped differently, a behind-the-ear hearing aid may need some kind of help to stay in place, like toupee tape. Some examples of ear malformations include smaller than usual outer ears (microtia), a blocked or closed ear canal (atresia), and malformed ear bones.
4. How open the parents, guardians, or child is to using a hearing aid: Even though this isn’t a solid rule, doctors do think it’s important that the child and their family are okay with using a hearing aid. If the child or their caregivers don’t entirely accept the hearing loss yet, they might not use the device as much as they should. Providing families with good, clear information and support can help them be confident in how to use the hearing aid and understand how much it can help. This encourages everyone to use and benefit from the hearing project.
5. How reliable the hearing test (audiogram) is: An audiogram is a graph that shows how well a person can hear sounds of different pitches and loudness. If a child’s audiogram isn’t complete or reliable, the hearing aid might make sounds too quiet or too loud. More time should be spent doing different tests to figure out the child’s true hearing ability. If a predicted audiogram is used as a last option, it needs a lot of thought to make sure it’s careful but still helpful. Only experts should do this.
6. Family’s communication choices: Some families, particularly those who primarily use sign language or come from the Deaf community, might not want their child to use a hearing aid. In these cases, a lot of advising and support should be given to ensure families understand what they’re deciding. If a child has hearing loss from birth, an experienced team should work with the family to make sure they’re fully supported in their decision.
When a Person Should Avoid Hearing Aid Fitting for Children
There are no clear reasons why a child with hearing loss, who could benefit from a hearing aid, shouldn’t get one. This is based on a hearing test, also called an audiometry test. However, whether a child should be given a hearing aid or not largely depends on both the child and their family. If the child or the family doesn’t want to use a hearing aid, then it may not be the best choice for them.
There could be a number of reasons for this. In some cases, because there’s a stigma around wearing a hearing aid, people might feel embarrassed to use them. Some families, especially if they’re part of the Deaf community, might prefer not to use hearing aids. Additionally, if a child has trouble with complex tasks, like putting in and taking out the hearing aid, they might not be good candidates for this device.
Equipment used for Hearing Aid Fitting for Children
During the process of fitting a hearing aid, a lot of specific and well-maintained equipment is necessary. Here are the tools and equipment needed for this process:
The main device needed is a computer that has hearing aid fitment and verification software installed. To connect the hearing aid to the computer, either programming cables or a wireless link device is used. The hearing aid itself is picked based on features like power, size, color, its ability to connect to other devices, its compatibility with FM radios, and its safety features.
Attachments such as earmolds or slim tubes are needed for behind-the-ear devices. If real ear measurements are used for the fitting, a few more pieces of equipment are necessary. These might include a test box or hearing aid verification equipment, tubes for taking measurements in the ear, and tubes for determining the difference between real ear and coupler measurements.
In addition to the above, there are certain items that may come in handy for the clinician:
They might use a demo hearing aid to visually explain the process to the family of the patient. Written instructions and information are also valuable. To maintain the hearing aid, a pack is usually provided that often includes: tubing puffer, battery checker or charger (for rechargeable hearing aids), moisture-removing tablets, cleaning tools, antiseptic wipes, stetoclip, and hearing aid case.
To help keep the hearing aid in place, retention devices like toupee tape, hearing aid clothing clips, and loop retainers can be used. Materials for speech testing may also be necessary. ‘Socks’, ‘shoes’, or ‘boots’ for FM radios, as well as ear-level receivers, can be required too. Lastly, medical tape might be used to help hold the tube for real-ear-measurement in place.
Who is needed to perform Hearing Aid Fitting for Children?
Fitting hearing aids for children should be done by a healthcare expert with special experience, often a hearing doctor (audiologist) who has extra training in child healthcare. The way to fit hearing aids in children is pretty close to how it’s done for adults. However, it needs a little more thought to make sure the fit is perfect and to check progress after the fitting. This is particularly important for children who haven’t learned to talk yet or those who can’t share their feelings.
A group of specialists coming from different fields like hearing doctors (audiologists), regular doctors (physicians), specialists in introducing deaf children to sounds and languages (early intervention specialists or teachers of the deaf), and speech and language therapists should be known and trusted by the child and their family before the hearing aid fitting takes place.
How is Hearing Aid Fitting for Children performed
It’s crucial that children who need air conduction hearing aids receive the correct fitting, based on trustworthy guidelines. These guidelines can come from well-known organizations like the American Speech-language Hearing Association and the British Society of Audiology. Here are the important steps to follow in this process:
1. Preparation: The details of the child’s hearing abilities are gathered and put into the fitting software. This makes sure the right prescription is calculated. Some information, such as gender and date of birth, can also affect the prescription. The hearing aid is then connected to the software so its settings can be adjusted.
This process can involve choosing between two prescriptions: Desired Sensation Level (DSL) or National Acoustic Laboratories (NAL). DSL was specifically made for kids to give a methodical formula for amplification. This helps bring about clearer speech. NAL also aims to boost speech clarity, along with focusing on the naturalness of sound. Both options have been shown to have similar outcomes for speech understanding in children.
2. Counseling the Family and the Child: Good counseling is extremely important to make sure the hearing aid is effective. It should be made sure that information on these points is clearly understood: benefits and expectations from the hearing aid, optimal timings to use it, how to care and clean the hearing aid, correct way to insert it, and how to promote its use. Any additional equipment given should also be explained.
3. Checking the Hearing Aid: For children who are too young or unable to report on the sound and loudness of the hearing aid, checking the hearing aid’s accuracy is critical.
There are two common ways to do this: Real-ear measurements (REMs) and Real-ear-to-coupler difference measurements (RECDs). RECDs can work well for very young children or those who can’t sit still for long. REMs are used to give ‘real-time’ verification of the hearing aid at the child’s ear level. Both methods consider the child’s ear canal’s effects on the incoming sound.
In general, the fitting of air conduction hearing aids for children might sound technical, but it’s actually a process of careful preparation, clear communication, and detailed checking of the device.
Possible Complications of Hearing Aid Fitting for Children
Hearing aids are a non-invasive option for those with hearing problems, which means they don’t involve any surgical procedures. Because of this, the risk of medical complications from using hearing aids is low. These devices can be very useful, especially for people with certain ear conditions that might make other treatments, like putting a small tube in the ear or using a hearing aid that’s attached to the bone, more risky.
For children, the bigger challenge is not fitting the hearing aids, but ensuring they use them consistently after fitting. The support and advice of professionals both before and after fitting the hearing aids are really important. They can teach families how to take care of the device and provide further help if needed to ensure the hearing aids are used in the best possible way.
In the weeks and months following the fitting, professionals might use a tool to track the use of the hearing aids. This can give them an idea of how regularly the patient is using the device. It also helps them understand if any adjustments are needed, any problems need to be fixed, or if the patient and their family need more counseling or instruction on using the hearing aids.
What Else Should I Know About Hearing Aid Fitting for Children?
Newborn hearing test programs and digital hearing aids have played a huge role in decreasing the long-term impact of hearing loss in children around the globe. When these aids are used correctly by trained experts following local and national guidelines, they help improve children’s language skills, education, and social wellbeing.