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Hearing aid

A hearing aid is a small electronic device that you wear in or behind your ear. It makes some sounds louder so that someone with hearing loss can listen, communicate, and participate more fully in daily activities. A hearing aid can help people hear more in both quiet and noisy situations. However, only about one in five people who would benefit from a hearing aid also uses one.

A hearing aid has three basic parts: a microphone, amplifier and speaker. The hearing aid receives sound through a microphone, which converts the sound waves into electrical signals and sends them to an amplifier. The amplifier increases the power of the signals and then sends them through a loudspeaker to the ear.

How can hearing aids help?

Hearing aids are especially helpful in improving the hearing and speech understanding of people with hearing loss that results from damage to the tiny sensory cells in the inner ear called hair cells. This type of hearing loss is called sensorineural hearing loss. The damage can be caused by illness, aging, or injury from noise or certain medications.

A hearing aid amplifies sound vibrations that enter the ear. Surviving hair cells detect the greater vibrations and convert them into neural signals that are passed on to the brain. The greater the damage to a person's hair cells, the more severe the hearing loss and the greater the amplification of the hearing aid needed to make up for the difference. However, there are practical limits to the amount of gain a hearing aid can provide. In addition, if the inner ear is too damaged, even large vibrations will not be converted into neural signals. In this situation, a hearing aid would not work.

How do I find out if I need a hearing aid?

If you think you may have hearing loss and could benefit from a hearing aid, see your doctor, who may refer you to an ENT or audiologist. An ENT specialist is a doctor who specializes in ear, nose and throat conditions and will investigate the cause of the hearing loss. An audiologist is a hearing care professional who identifies and measures hearing loss and performs a hearing test to assess the type and degree of loss.

Are there different types of hearing aids?

Styles of hearing aids

5 types of hearing aids. Behind-the-ear (BTE), mini-BTE, in-the-ear (ITC), in-canal (ITC) and full-in-canal (CIC)
Source: NIH / NIDCD

  • A behind-the-ear (BTE) hearing aid consists of a hard plastic cover that is worn behind the ear and is connected to a plastic earmold that fits in the outer ear. The electronic parts are kept in the case behind the ear. Sound travels from the hearing aid through the earmold to the ear. BTE devices are used by people of all ages for mild to profound hearing loss.

    A new kind of BTE device is an open-fit hearing aid. Small, open-fit devices fit completely behind the ear, with only a narrow tube inserted into the ear canal, leaving the canal open. For this reason, open-fit hearing aids can be a good choice for people who suffer from wax build-up, as these types of hearing aids are less likely to be damaged by such substances. In addition, some people prefer the open-fit hearing aid because their perception of their voice does not sound 'blocked'.

  • In-the-ear (ITE) hearing aids fit completely into the outer ear and are used for mild to severe hearing loss. The housing with the electronic components is made of hard plastic. Some ITE aids may have additional features installed, such as a telecoil. A telecoil is a small magnetic coil that allows users to receive sound through the circuitry of the hearing aid, rather than through the microphone. This makes it easier to hear conversations on the phone. Telecoil also helps people hear in public buildings that have special sound systems installed called induction loop systems. Induction loop systems can be found in many churches, schools, airports and auditoriums. ITE aids are usually not worn by young children as the covers often need to be replacedgene as the ear grows.

  • Canal aids fit in the ear canal and are available in two styles. The in-the-canal (ITC) hearing aid is made to match the size and shape of a person's ear canal. A full in the canal (CIC) hearing aid is almost hidden in the ear canal. Both types are used for mild to moderately severe hearing loss.

    Because they are small, channel aids can be difficult to adjust and remove. In addition, channel aids have less space available for batteries and additional devices, such as a telecoil. They are not usually recommended for young children or those with severe to profound hearing loss, because their limited size limits their strength and volume.

Do all hearing aids work the same way?

Hearing aids work differently depending on the electronics used. The two main types of electronics are analog and digital.

Analogue aids convert sound waves into electrical signals, which are amplified. Analog / adjustable hearing aids are tailor-made to meet the needs of each user. The device is programmed by the manufacturer to the specifications recommended by your audiologist. Analog / programmable hearing aids have more than one program or setting. An audiologist can program the tool using a computer, and you can change the program for different listening environments - from a small, quiet room to a busy restaurant to large, open spaces, such as a theater or stadium. Analog / programmable circuitry can be used in all types of hearing aids. Analog tools are generally cheaper than digital tools.

Digital tools convert sound waves into numerical codes, similar to a computer's binary code, before amplifying them. Because the code also contains information about the pitch or loudness of a sound, the tool can be specially programmed to boost some frequencies more than others. Digital circuitry gives an audiologist more flexibility in tailoring the device to the user's needs and specific listening environments. These aids can also be programmed to focus on sounds coming from a specific direction. Digital circuits can be used in all types of hearing aids.

Which hearing aid works best for me?

Which hearing aid is best for you depends on the type and severity of your hearing loss. If you have hearing loss in both ears, two hearing aids are generally recommended as two devices deliver a more natural signal to the brain. Hearing in both ears can help you understand speech and determine where the sound is coming from.

You and your audiologist must choose the hearing aid that best suits your needs and lifestyle. Price is also an important consideration as hearing aids range from hundreds to several thousand dollars. As with other equipment purchases, style and features affect costs. However, don't just use price to determine the best hearing aid for you. Just because one hearing aid is more expensive than another doesn't mean it better suits your needs.

A hearing aid does not restore normal hearing. With practice, a hearing aid will increase your awareness of sounds and their sources. You want to wear your hearing aid regularly, so choose one that is convenient and easy to use. Other features to consider include parts or services under warranty, estimated maintenance and repair schedule and costs, options and upgradeability, and the hearing aid company's reputation for quality and customer service.

What questions should I ask before buying a hearing aid?

Before purchasing a hearing aid, ask your audiologist the following important questions:

  • Which features are most useful to me?
  • What are the total costs of the hearing aid? Do the benefits of newer technologies outweigh the higher costs?
  • Is there a trial period to test the hearing aids? (Most manufacturers allow a 30 to 60 day trial period during which devices can be returned for a refund.) What costs are non-refundable if the devices are returned after the trial period?
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