Hearing Aids

It is a common belief that hearing aids will solve hearing problems. This is not always the case, but they can help many hearing problems. On the other hand, only one in four of those who would benefit from a hearing aid, actually wears one.

Hearing aids have improved considerably since the conspicuous ear trumpets used in the 18th and 19th centuries. Alexander Graham Bell’s mother used one until, as a child, Bell began to communicate with his mother directly in her ear – a system both found more beneficial since it brought them closer together physically. In the last few decades of the 20th century, significant progress was made both in the size of the apparatus and in its technical ability.

Some people resist wearing hearing aids. Reasons vary, but usually, it is because of an unwillingness to accept hearing loss, the cost of the device, or reports of bad experiences by others. One of the greatest deterrents is the fear of social stigma – a concern that the device will be considered a sign of old age, incompetence, inferiority, or unattractiveness. Such concerns have little basis in fact and is mainly a perception in the mind of the wearer.

Selecting a Hearing Aid

Many types of hearing aids are available. Although the technology is constantly improving, the basic concept remains the same – to make sounds louder and clearer. All hearing aids work by collecting sounds from the environment via a small microphone, amplifying them, and sending the sounds into the user’s ear by way of a loudspeaker. The amplified signal stimulates the inner ear, which activates nerve fibers that carry the sound impulses to the brain.

When choosing a hearing aid, the decision will involve style, size, and circuitry features, as well as whether to use one or two devices. These decisions can be confusing and the reason why guidance is necessary. For one thing, you may have heard that digital hearing aids provide the best sound. What may not be clear is that digital refers to the technology of the electrical componenets and not to the particular size of the hearing aid. Style and circuitry, along with size, are separate issues. Any circuitry can be placed in any style of hearing aid.

Another issue is whether or not to wear two hearing aids. In most cases, wearing two (binaural) hearing aids has many advantages over wearing only one (monaural). When two are used, more information is going to the brain. Signals reaching each ear are slightly different, just as it is in normal hearing. This can make it easier to hear speech in situations with background noise.

Two aids also provide more balanced hearing since there will not be a bad or good side. Sound will be more localized, making it easier to locate. Another advantage is that neither device will have to be turned up as loudly, which will reduce feedback and increase comfort.

Circuitry Types

Hearing aid electronics, or circuitry, refers to the components inside the device. The electrical technology is designed or programmed to amplify certain frequencies more than others. The frequencies chosen for amplification will compensate for the corresponding damaged hair cells in the cochlea. The frequency range to which a hearing aid is programmed is called the frequency response. Hearing aid circuitry may be basic analog, programmable analog, or digital.

Styles and Types of Hearing Aids

Since hearing aids come in various styles, sizes, and the way they are placed in the ear, it is vital that a qualified hearing aid specialist be consulted for the process. Most often, a hearing aid must be fitted. To do this, the hearing aid dispenser will insert a soft waxlike material into the ear to make an impression of the ear canal and outer ear. This is an essential part of the hearing aid fitting, ensuring that the aid will fit properly. Some styles are almost invisible and fit deeply in the ear canal, but the most widely sold aids are those that fit partially in the ear canal or in the bowl of the outer ear.

Generally the smaller the hearing device, the less powerful it is and the shorter the battery life, making it more costly in the long run. Smaller aids are also more likely to produce feedback – the high-pitched whistle or other noise that is amplified when it is picked up by the microphone and re-amplified. New technology is helping to reduce this bothersome problem.

With so many styles from which to choose, it is easy to choose one only for looks. But it must be remembered that function is the most important reason for purchasing a hearing aid: the greater the hearing loss, the larger the hearing aid that will be necessary. The size and shape of the ear and ear canal will also determine the style needed. In-the-ear styles can be difficult to fit in smaller ears. The ability to handle a small hearing aid style may also be a factor, especially if there is limited finger dexterity or if the wearer is a small child.

Completely-in-the-canal (CIC) hearing aids are the smallest available. All parts, including the battery, are contained in a tiny case that fits deep inside the ear canal. A thin, plastic pull cord sticks out into the bowl-shaped area of the ear to help in removal. The CIC is appropriate for mild to moderate hearing loss but should never be used on infants or children. This device helps reduce wind noise, but it is also the least powerful hearing aid style. In addition, CIC units have less space for such add-ons as volume control or directional microphones, are more expensive than other styles, and are smaller so they will have to be replaced more often.

In-the-canal (ITC) hearing aids fit partly in the ear canal but not as deeply as a CIC model. The edge of the ITC unit extends into the bowl of the ear. This style can accommodate mild to moderately severe hearing loss, but it is not appropriate for infants or children. It is less noticeable and potentially more powerful than a CIC aid with more opportunity for add-ons. However, it can be difficult to handle and insert as well as replacing batteries. It is also rather expensive.

In-the-ear (ITE) style fills most of the bowl-shaped area of the outer ear. It is appropriate for mild to severe hearing loss and can be more powerful than those that fit into the ear canal. It can also accommodate more add-ons and is appropriate for a wide range of hearing loss. The battery is slightly larger and easier to insert than the in-the-canal style, but it does pick up more wind noise. ITE components are held in a small plastic container called the casing. In a BTE style, the casing rests behind the ear and is connected to an earpiece or earmold by a plastic tube. The earpiece is custom-made to fit into the ear so that it will direct sound into the ear canal.

Components consist of:

Behind-the-ear (BTE) aids have two parts. A small plastic case that rests behind the ear contains the hearing aid circuitry (microphone, amplifier, and loudspeaker). The case is connected by plastic tubing to a custom-made earmold that directs the amplified sound into the ear. BTE aids are appropriate for almost all types of hearing loss and for people of all ages. However, they are often perceived as being old-fashioned and not technologically advanced when, in fact, they have all the modern electronic and digital technology as any other style.

In some cases, BTE units can provide the greatest improvement in hearing. They are the most powerful hearing aids and can be adjusted for any degree of hearing loss. BTE aids are the best style for infants, children, and those with more severe hearing loss. They are also the easiest to maintain, partly because replacing the battery is easier as well as the fact that they usually require fewer repairs. On the other hand, some people simply do not have enough space between their ear and the side of the head to accommodate this style. BTE aids may pick up more wind noise than smaller aids do.

Many BTE and ITE hearing aids are equipped with a telecoil. This is helpful for listening on the telephone. Normally, a hearing aid is sensitive to all sound waves, but when the telecoil is turned on, the aid amplifies only electromagnetic waves from the telephone’s receiver. This means that the telephone signal is transmitted directly into the hearing aid without any background noise being amplified. When purchasing a phone, it is wise to ask about hearing aid compatibility. If the salesperson does not know, try out the system first. The telecoil can also be used with FM systems and inductive loop systems.

Disposable hearing aids are just that – disposable. Their sound quality can be as good as standard aids and they offer easier maintenance. Disposable aids are ITC types designed to be worn for about 40-70 days and then discarded. Using disposable aids may eliminate maintenance problems caused by moisture and wax buildup, as well as replacing the batteries. Disposable devices can be fitted at a hearing evaluation center and can be taken right away. With standard hearing aids, a mold of the ear must be made and a second appointment needed for fitting. However, disposable hearing aids will not fit all or meet all needs since they are not custom fitted. They also have less adjustable circuitry and no special features. In addition, there is the ongoing expense of purchasing a new aid every other month.

Eye-glass types have all parts of the aid fitted into the frames of eyeglasses. Clear plastic tubing connects the bow to an earmold. However, very few people wear this type anymore.

Body hearing aids are large and very powerful aids used for those who have a profound hearing loss. All parts are contained in a case worn on the body; that is, it is clipped to a bra or pocket. A cord connecting the case to the receiver runs along the neck, and the receiver then snaps into an earmold with wires extending from the receiver to an earmold.

Implantable hearing aids are an alternative to standard hearing devices for those with moderate to severe sensorineural hearing loss (damage to the inner ear). These devices operate differently from other types. Standard hearing aids converts sound into electrical signals and amplifies them. Implantable devices work on principles of mechanical vibration. They conduct sound by vibrating the middle ear bones directly to stimulate the inner ear. These devices are not recommended for those with conductive hearing loss (outer or middle ear) or in those with recurrent middle ear infections.

Still under development, implantable hearing aids use a tiny electromagnet attached to the bones of the middle ear and an external unit that stimulates the magnet. For some units, a receiver is surgically implanted into the skull behind the ear. An external amplifier is held in place by a magnet over the implanted receiver. A wire leads from the receiver to the electromagnet attached to one of the middle ear bones. Other units have an external processor containing both amplifier and receiver that is worn in or behind the ear, similar to standard hearing aid styles. These aids are put into place during an outpatient surgical procedure that lasts from 30 minutes to 2 hours. Implantable devices are expected to produce a clearer, more natural sound, although research has not confirmed this as yet. On the downside, it can cost as much as $18,000 per ear, depending on which device is selected and the type of anesthesia necessary for the procedure.

Frequency Modulation (FM) Systems: Many people are familiar with radio FM frequencies. Similiar systems for the hearing-impaired transmit sounds via radio waves, just like a miniature radio station. They operate on special radio frequencies assigned by the FCC (Federal Communications Commission). FM systems are commonly installed in locations where listening may become difficult or large audiences may gather.

With FM systems, sounds broadcast by a microphone, sound system, radio, television, or stereo are directed by a wireless radio transmitter to small, portable receivers worn by listeners in the audience who have a hearing impairment. They can also be used with hearing aids that have a telecoil or a direct audio input. To use the telecoil, a small looped cord or necklace of wire is worn, which converts the FM signal into electromagnetic waves that are piced by the the telecoil. If there is no telecoil, the FM system can be linked to a hearing aid using a small adaper called a boot. Several styles of BTE hearing aids have a built-in FM receiver.

Infrared Systems for the hearing-impaired, transmit sounds via light waves to receivers worn by the listener. Like FM systems,infrared systems are used in locations where hearing is difficult or where large groups of people gather. Infrared technology is also commonly equipped in TV sets for home use.

When used in a large auditorium, an infrared light emitter is plugged into an existing public-address or sound system. The infrared light waves transmit sound to a portable, lightweight receiver, which may be worn like a headphone or can be used with a hearing aid that has a telecoil. For use with a television, the volume can be set on the TV that is comfortable for others. The infrared transmitter sends the TV signal to the receiver, and the wearer can then adjust his own volume.

The infrared receiver must be in the transmitter’s direct line of broadcast in order to function properly. Since sunlight can interfere with the signal, these systems are not a good choice for use outdoors. However, because infrared light waves are broadcast along a confined path and not emitted in all directions, they provide more privacy than do the FM systems.

Inductive Loops, also called audio loop systems, are less commonly used than FM or infrared systems. Inductive loop systems transmit sounds using an electromagnetic field created by a loop of wire installed around the listening area. An amplifier and microphone transmit sound in the form of an electric current that flows through the loop, creating the electromagnetic field. Hearing aids equipped with telecoils receive these signals as sounds. Separate receivers can be provided to people who do not have a telecoil feature with their hearing aids. Inductive loop systems can be permanently installed in the floors of large auditoriums or chambers and can be set up as needed. On the downside, reception of these systems is susceptible to elecrical interference.

Contralateral Routing of Signal (CROS) and Bilateral Routing of Signals (BICROS) are instruments designed to transmit sound from a microphone located near a nonfunctional ear to a receiver on the other ear. The CROS aid is used if the better ear has close to normal hearing while the BICROS aid is used if the better ear requires amplification in its own right.

Special Features

Many people are not aware of the numerous options in technology, including computer software that can make communication easier for the hearing-impaired. An audiologist can help inform patients of the many options open to them and which ones would be best for their needs.

Some of the special added features available for hearing aids include:

Tips for Buying a Hearing Aid

Cost Factors

The cost of hearing aids varies considerably. A good basic analog ranges from $600 to $1,500. A programmable analog device costs between $750 and $1,900 on average. A digital aid ranges from $800 to $3,000. Naturally, costs double if two hearing aids are used.

Although the cost may seem expensive, hearing aids do improve the quality of life and are generally worth the investment. Most private insurances and Medicare do not cover the cost. A few companies have a reimbursement clause as part of their employee benefit package. Qualified veterans may be eligible for free hearing aids and services. Some fraternal or charitable organizations provide financial assistance for those who meet the requirements.

Caring for the Hearing Aid

Proper care of the hearing aid is essential in ensuring that it lasts as long as possible.