Hearing aid facts for kids

In-the-canal hearing aid

A hearing aid is a small electronic device that helps people with hearing loss hear sounds better. It makes sounds louder and clearer, so you can understand speech and enjoy the world around you. Hearing aids are special medical devices. They are different from simple sound amplifiers, which just make all sounds louder.

Long ago, people used ear trumpets. These were like funnels that collected sound and directed it into the ear. Today's hearing aids are much more advanced. They are like tiny computers for your ears!

Modern hearing aids use smart technology to process sounds. They can make speech clearer and reduce annoying background noise. This helps you hear comfortably in many different places.

Each hearing aid is custom-tuned for the person wearing it. A hearing expert, like an audiologist, helps set it up. They make sure the hearing aid matches your specific hearing needs and lifestyle. Getting the right fit is key to how well a hearing aid works. Most hearing aids today are digital, using advanced computer chips to process sound. Other devices, like bone-anchored hearing aids and cochlear implants, also help with hearing.

Understanding Hearing Aids

Why People Use Hearing Aids

Hearing aids help with different kinds of hearing loss. This includes problems with the inner ear, outer ear, or hearing in only one ear. A hearing expert decides if a hearing aid is right for you. They also help choose the best device based on your specific needs.

How much a hearing aid helps depends on many things. These include the type of hearing loss and the technology of the device. Your own lifestyle and how motivated you are also play a role. Some newer hearing aids can even be adjusted by you at home.

Remember, hearing aids don't fix hearing loss completely. They are tools to make sounds easier to hear. For example, if tiny cells in your inner ear are damaged, sounds might seem too quiet. A hearing aid makes these sounds louder.

Sometimes, hearing loss can make it hard to understand speech, especially in noisy places. Modern hearing aids use special computer programs to help with this. They try to make speech clearer. Hearing aids often work very well for hearing loss caused by blockages in the ear. This is because the inner ear can still send signals to the brain once sounds are loud enough.

Some common challenges with hearing aids used to be whistling sounds or feeling like your ear is plugged. Today, new technology helps control these issues. This makes wearing a hearing aid much more comfortable.

Getting the Right Fit

Experts use different ways to check how well a hearing aid works. One way is audiometry, which tests your hearing in a quiet room. They measure how soft a sound you can hear. This helps them understand your hearing needs.

Another way is for you to share your own experiences. You can tell them how the hearing aid helps you in daily life. This feedback is very important.

When checking how well a hearing aid helps, experts look at a few things:

• How often you use your hearing aid.
• How well you understand speech with it.
• How much you like and benefit from it.

A very accurate way to adjust a hearing aid is called real ear measurement. This uses a tiny microphone placed near your eardrum. It measures the sound coming from the hearing aid right inside your ear. This helps ensure the sound is just right for you.

Different Kinds of Hearing Aids

Hearing aids come in many shapes and sizes. They also have different levels of power and internal parts. Here are some of the main types:

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  An old body-worn hearing aid from around 1944.

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  An older body-worn hearing aid using transistors.

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  Two BTE (Behind-the-Ear) hearing aids with custom earmolds.

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  Receiver-in-the-canal (RIC) hearing aids.

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  An ITE (In-the-Ear) hearing aid.

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  A CIC (Completely-in-the-Canal) hearing aid.

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  A person wearing a bone-anchored hearing aid.

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  A hearing aid being placed in an ear.

Body-Worn Aids: The First Portable Kind

Body-worn aids were among the first portable electronic hearing aids. Harvey Fletcher invented them at Bell Laboratories. They have a small case, about the size of a deck of cards. This case holds the electronics and battery.

A wire connects the case to an earmold in your ear. The earmold has a tiny loudspeaker. You can carry the case in a pocket or on a belt. These aids can be powerful and have long battery life. They are also less expensive.

Behind-the-Ear Aids: Common and Versatile

A modern behind-the-ear hearing aid. The audio tube to the speaker is barely visible.

A modern behind-the-ear hearing aid with a minicell battery.

Behind-the-ear (BTE) hearing aids are very popular. They have a small case that rests behind your ear. A thin tube or wire connects this case to an earmold or dome tip inside your ear canal. The case holds the electronics, controls, battery, and microphones.

Sometimes, the speaker (receiver) is in the case. Other times, it's in the earmold (called receiver-in-the-canal, or RIC). RIC aids are often smaller and good for active people. BTEs can provide strong sound, making them suitable for more severe hearing loss. They are also durable and easy to use. Many children wear BTEs because they are tough and easy to connect to other listening devices.

In-the-Ear Aids: Small and Custom-Made

In-the-ear (ITE) aids fit right inside the outer part of your ear. They are custom-made to fit your unique ear shape. Being larger than some other types, they can have more features and are easier to handle.

ITEs are good for mild to some severe hearing losses. Modern ITEs have technology to prevent whistling sounds (feedback). They are also becoming more suitable for children, with new flexible materials. ITEs can connect wirelessly to other systems, like FM systems.

• Completely-in-the-canal (CIC) aids are very tiny. They fit deep inside your ear canal and are almost invisible. They are best for mild to moderately severe hearing loss. CICs are great for phone calls and reduce wind noise. However, their small size means shorter battery life and smaller controls.
• In-the-canal (ITC) aids are a bit larger than CICs. They are also placed deep in the ear canal and are barely visible. ITCs are easier to handle than CICs and can have directional microphones.

ITE hearing aids are often more expensive because they are custom-made. An audiologist takes a mold of your ear. This mold is used to create a 3D model of your ear. Then, the hearing aid shell is printed using special technology.

Invisible Aids: Hidden Helpers

Invisible-in-canal (IIC) hearing aids fit completely inside your ear canal. They are so deep that they are almost impossible to see. This deep fit makes hearing feel more natural. Your ear can collect sound as it normally would.

Some IIC models let you use your phone as a remote control. You can change settings without touching the aid. IIC aids are great for younger and middle-aged users. They might be harder for older people with unsteady hands to manage.

Long-Wear Aids: For Continuous Use

Extended wear hearing aids are placed deep in the ear canal by a professional. You can wear them for 1-3 months without taking them out. They are made of soft material that fits your ear. These aids help with mild to moderately severe hearing loss.

Because they are close to the eardrum, they offer clear sound and reduce feedback. They are also protected from moisture and earwax. This makes them great for active people who exercise or shower. They are invisible to others, which many users like.

CROS Aids: For One-Sided Hearing

A CROS hearing aid helps if you have hearing loss in only one ear. It picks up sound from the ear that doesn't hear well. Then, it sends that sound wirelessly to the ear that hears better. This helps you hear sounds from all directions.

CROS aids look similar to BTE hearing aids. They can help you understand sounds better, especially from your weaker side.

Bone-Anchored Aids: Using Bone to Hear

A bone anchored hearing aid (BAHA) is a special hearing device. It uses your skull to send sound to your inner ear. A small part is surgically placed in the bone behind your ear. The sound processor then attaches to this part.

For people with certain types of hearing loss, the BAHA bypasses the outer and middle ear. It sends vibrations directly to the inner ear. This helps the nerve fibers in the inner ear pick up the sound. BAHAs are also useful if you have hearing in only one ear. They send sound from the deaf side to the working inner ear.

Young children can wear a BAHA on a soft band around their head. When their skull bone is strong enough, a small titanium post can be implanted. The surgery is simple and has few risks. If someone decides they don't want the BAHA, it can be easily removed.

Eyeglass Aids: Hearing and Seeing Combined

1940s adult and child combined hearing aid glasses, on display at Thackray Museum of Medicine.

Years ago, some hearing aids were built into the side arms of eyeglasses. This was popular when thick-rimmed glasses were common. However, it meant you had to wear both your glasses and hearing aids together.

Today, people can use small in-the-ear aids or BTEs that fit neatly with glasses. Still, eyeglass aids can be useful in special cases. For example, if you have hearing loss mainly in one ear, sound can travel through the glasses frame to the better ear.

• Bone conduction spectacles send sound through the bone behind your ear. A receiver on the glasses arm presses against the bone. This sends vibrations to the inner ear. They are often used for certain types of hearing loss or if regular aids can't be worn.
• Air conduction spectacles have small hearing aids attached to the glasses arms. When you take off your glasses, the hearing aids come off too.
• Directional spectacles are newer "hearing glasses." They have multiple microphones on each side. These microphones can focus on sounds coming from in front of you. This helps you hear speech better in noisy places by reducing background sounds.

Stethoscope Aids: For Medical Pros

These hearing aids are made for medical practitioners who have hearing loss. They are built into the speaker of a stethoscope. This amplifies the sounds from the stethoscope, making them easier to hear.

Hearing Aid Apps: Smart Devices as Aids

Hearing aid applications (HAAs) are software programs for smartphones or tablets. They turn your mobile device into a hearing aid. The device's microphone picks up sound. The app then processes and amplifies the sound. It sends the improved sound to your headphones or headset.

These apps can correct hearing for each ear separately. They work with both wired and wireless headphones. HAAs usually have a setup mode where you test your hearing. Then, in hearing aid mode, they adjust sounds based on your test results. They can also reduce background noise and whistling.

HAAs offer several benefits:

• They don't cause the same feeling of "wearing a hearing aid."
• They can provide high-quality sound and long battery life.
• They can use advanced sound processing.
• They are easy to control, even for people with limited hand movement.
• They are resistant to earwax and moisture.
• The microphone and speaker are far apart, which helps prevent feedback.
• You don't need to buy a separate device.

However, HAAs also have some downsides. The microphone isn't in your ear, so it doesn't use your ear's natural shape to gather sound. They can also be more noticeable and less comfortable than tiny hearing aids.

The Technology Inside Hearing Aids

Connecting Hearing Aids to Other Devices

Phone Compatibility: Clear Calls

A sign in a train station explains that the public announcement system uses a "Hearing Induction Loop" (audio induction loop). Hearing aid users can use a telecoil (T) switch to hear announcements directly through their hearing aid receiver.

Hearing aids and phones work best together when they connect well. This means you can hear clear, easy-to-understand sound. This applies to all types of phones: wired, cordless, and mobile.

There are two main ways they connect:

• Acoustically: The hearing aid's microphone picks up the sound from the phone's speaker.
• Electromagnetically: A special coil inside the hearing aid, called a "telecoil" or "T-coil," picks up the signal from the phone's speaker.

The electromagnetic (telecoil) method is usually better. It often turns off the hearing aid's microphone, so you hear less background noise. The sound is clearer because it's a direct electronic connection. For this to work, the phone needs to be "hearing-aid compatible."

Some mobile phones can create static noise with telecoils. A trick is to use a wired headset with your phone. Place the headset near your hearing aid, and hold the phone further away. Another option is a "neckloop" that plugs into your phone. It sends sound wirelessly to your hearing aid's telecoil.

The American National Standards Institute (ANSI) rates phone compatibility. Ratings go from M1 (worst) to M4 (best) for microphone mode. For telecoil mode, they go from T1 (worst) to T4 (best). An M4/T4 rating means the phone works great in both modes.

Wireless Connections: Staying Connected

Many modern hearing aids are wireless. One hearing aid can talk to the other, so changing a setting on one changes both. FM listening systems are also becoming integrated. A small wireless microphone can be given to a friend or teacher. Their voice is sent directly to your hearing aids. This helps you hear them clearly, even in noisy places or from a distance.

FM systems can also connect to TVs or stereos. The newest wireless technology uses 2.4 gigahertz Bluetooth. This connects hearing aids to devices like TV streamers or Bluetooth-enabled phones. Often, a small "streamer" device worn around your neck or in a pocket helps make this connection.

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  Oticon hearing aids designed for use with Bluetooth wireless devices.

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  A Phonak wireless FM system.

In many countries, FM systems are very important for children with hearing loss. More adults are also finding them helpful. Many theaters and lecture halls now have special listening systems. These send sound directly to your hearing aid, reducing background noise.

Directional Microphones: Focusing on Sound

Older hearing aids often had omnidirectional microphones. These picked up sounds equally from all directions. Modern hearing aids often have directional microphones. These focus on sounds coming from one direction, like someone speaking in front of you.

This helps reduce background noise and makes speech clearer. Directional microphones are very helpful in noisy places like restaurants. Many hearing aids can switch between omnidirectional (for quiet places) and directional (for noisy places) modes. Some even switch automatically.

Adaptive directional microphones can automatically adjust where they focus. They try to amplify the speech you want to hear and reduce interfering sounds. This can greatly improve understanding speech in noise.

Telecoils: Hearing Loops in Action

A sign in a train station explains that the public announcement system uses a "Hearing Induction Loop" (audio induction loop). Hearing aid users can use a telecoil (T) switch to hear announcements directly through their hearing aid receiver.

Telecoils, or T-coils, are tiny devices inside hearing aids or cochlear implants. They work with audio induction loop systems. These loops create an electromagnetic field that T-coils can detect. This allows sound from public address systems or TVs to go directly into your hearing aid.

T-coils help filter out background noise. They are common in churches, shops, and train stations in some countries. In the US, they are becoming more popular. T-coils can sometimes pick up buzzing sounds from other electromagnetic fields. These can come from computer monitors or older fluorescent lights.

Audio Boots and Direct Input

A hearing aid with an audio boot.

An audio boot or audio shoe is an electronic accessory for hearing aids. It fits onto the end of a behind-the-ear hearing aid. It connects the hearing aid to other devices. These can include FM systems, cellphones, or digital music players.

A direct audio input connector.

Direct audio input (DAI) means the hearing aid connects directly to an external sound source. This could be a CD player or an assistive listening device. DAI provides a clearer sound signal than using a T-coil with regular headphones. It also has less interference. An audio boot is one way to use DAI.

The Technology Inside Hearing Aids

Every electronic hearing aid has a microphone, a speaker (called a receiver), a battery, and electronic parts. These electronic parts can be analog or digital.

Analog vs. Digital Processing

• Analog hearing aids make all sounds louder. This means speech and background noise are amplified together. Early electronic hearing aids used analog technology.
• Digital hearing aids (DHAs) are much smarter. They process sound using computer chips. Before sending sound to the speaker, the DHA analyzes it. It can make specific frequencies louder based on your hearing needs. It can also adjust to different environments, like a noisy street or a quiet room.

Digital hearing aids offer many advantages:

• They can "learn" and adapt to your preferences.
• They effectively reduce whistling sounds (acoustic feedback).
• They use directional microphones smartly.
• They can handle a wider range of frequencies.
• They offer flexible sound amplification for your specific hearing.
• They connect better to other devices like smartphones.
• They reduce background noise for more comfort.
• They can even help distinguish speech from other sounds.

Digital Hearing Aids: Smart Sound

Block diagram of a digital hearing aid.

In digital hearing aids, both the sound and control circuits are fully digital. A hearing expert programs the aid using a computer. This allows for very precise adjustments for each person. Digital technology enables many features that analog aids cannot offer.

For example, digital aids can amplify certain frequencies more than others. They provide better sound quality. They can also have multiple programs for different listening situations. These programs reduce feedback, lower background noise, and adapt to loud or soft environments. They can even shift high-frequency sounds you might miss to lower frequencies you can hear better.

Digital aids also allow for wireless connections. They can send control signals between two hearing aids for balanced sound. They can also connect wirelessly to external devices. This includes mobile phones, music players, and remote microphones. This helps you communicate better in many situations.

Apps vs. Digital Aids: What's the Difference?

Smartphones have all the parts needed to act as a digital hearing aid. They have a microphone, a digital processor, and speakers. Hearing aid apps use these parts to amplify and process sound in real time. They can correct hearing for each ear separately using stereo headphones.

You can adjust hearing aid apps yourself. They often include a hearing test to set up the device for your comfort. However, these app-based tests are not the same as a professional audiometry test. They cannot be used for a medical diagnosis.

While convenient, hearing aid apps are not a full replacement for medical-grade digital hearing aids. Digital hearing aids are certified medical devices. They are precisely adjusted by a doctor based on professional audiometry.

PSAPs vs. Hearing Aids: Know the Difference

Personal Sound Amplification Products (PSAPs) are different from hearing aids. The FDA classifies PSAPs as "personal sound amplification devices." They are for people who do not have hearing loss. PSAPs simply make sounds louder.

People use PSAPs for things like hunting, birdwatching, or hearing the TV better. They don't require a medical prescription. Some PSAPs are basic, while others have features like directional microphones and noise filters. Some people now call these "OTC hearing aids."

App Evolution: More Than Just Music

There are now audio players designed for people with hearing loss. These apps amplify music based on your hearing needs. They help restore a natural perception of music. Like hearing aid apps, their settings are based on your personal audiogram.

Other apps combine music adaptation with hearing aid functions. They can amplify ambient sound while you listen to music. Some applications also help people with hearing loss watch videos and listen to the radio more comfortably.

Getting Used to a Hearing Aid

When you first start using a hearing aid, it takes time to get used to it. Hearing experts design aids to make this process as easy as possible. But your brain and ears still need to adapt to new sounds.

The process of adapting involves a few steps:

• Initial setup of the device.
• Fine-tuning the settings.
• Getting used to the new way of hearing.

Your brain is amazing and can adapt. But it might not process amplified sounds correctly at first. The hearing aid might feel unusual in your ear. Sounds might seem unnatural, metallic, too loud, or too quiet. You might also hear a whistling sound.

Hearing aids don't offer instant perfect hearing. The adjustment period can last from a few hours to several months. It's important to wear your hearing aid regularly. You should also visit your audiologist for check-ups and adjustments.

A Look Back: Hearing Aid History

Early Hearing Aids

Madame de Meuron with an ear trumpet.

The first hearing aids were ear trumpets, created in the 17th century. These were external devices. They gathered sound and directed it into the ear canal. They also helped block out other noises.

The invention of the telephone helped lead to modern hearing aids. The first electric hearing aid, called the "akouphone," was created around 1895 by Miller Reese Hutchison. By the late 20th century, digital hearing aids became available.

The carbon microphone, transistors, and computer technology all helped hearing aids evolve.

The Digital Revolution

The journey to digital hearing aids began in the 1960s. Scientists used large computers to simulate how sound could be processed. This helped them study different ways to improve hearing. In 1967, Harry Levitt used these simulations to model a hearing aid.

In the 1970s, hybrid hearing aids appeared. These combined analog parts for sound processing with digital parts for control. The digital part could be programmed by a computer. This made the aids more flexible.

The real breakthrough came in the early 1980s. A team at Central Institute for the Deaf created the first fully digital, wearable hearing aid. Maynard Engebretson, Robert E Morley Jr., and Gerald R Popelka were key inventors. Their work led to a US Patent in 1985.

This first digital aid processed all sound in binary form. It converted external sound into digital code, processed it, and then converted it back to analog sound. It also included features like self-calibration and noise reduction. These early digital chips were large. But they quickly became smaller, more powerful, and used less energy. Today, almost all hearing aids are fully digital. They include advanced features and wireless technology.

Rules and Safety for Hearing Aids

Hearing aids are medical devices. Most countries have rules to make sure they are safe and work well. These rules help protect people who use hearing aids.

In the United States, the FDA (Food and Drug Administration) sets rules for hearing aids. In 2017, the Over-the-Counter Hearing Aid Act was passed. This law created a new type of hearing aid. These aids are for mild to moderate hearing loss. They can be bought directly by consumers without needing a doctor's visit. The FDA finalized these rules in August 2022. This made it easier for people to get hearing aids.

How Much Do Hearing Aids Cost?

The cost of hearing aids can vary a lot. In some countries, public healthcare systems provide free or discounted hearing aids.

For example, in Australia, eligible citizens can get a basic hearing aid for free. They can pay extra to upgrade to a more advanced model. In the UK, the NHS provides digital BTE hearing aids free of charge.

In the United States, many private health insurance plans do not cover hearing aids. So, people often pay the full cost themselves. A single hearing aid can cost anywhere from $500 to over $6,000. However, some state programs can help with costs for severe hearing loss. Research has shown that hearing aids can help reduce the impact of hearing loss on a person's income.

Powering Your Hearing Aid: Batteries

Most modern hearing aids use small, disposable zinc-air batteries. These are also called button cell batteries. Older hearing aids used mercury batteries, but these are now banned in most places.

Hearing aid batteries are usually identified by a number or the color of their packaging. They fit into a rotating door on the hearing aid. The flat side is positive, and the rounded side is negative.

These batteries typically provide 1.35 to 1.45 volts of power. The type of battery depends on the hearing aid's size and how much power it needs. Batteries usually last between 1 and 14 days, assuming 16 hours of use per day.

Research

Scientists are also studying how hearing aids can help with tinnitus. Tinnitus is a condition where you hear ringing or buzzing sounds in your ears. Proper amplification from hearing aids may help manage these sounds.

See also

In Spanish: Audífono para niños