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 hear better.

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.

• Basic analog is a conventional type of electrical signal – or a copy of the sound waves in the environment. The analog signal is then amplified so that it can be better heard. An audiologist or hearing aid specialist will select different components and settings based on the type of hearing loss. If the hearing aid has a volume control, it can be adjusted by the wearer. This type of circuitry is more appropriate for people who do most of their communicating in relatively quiet situations. It is also the least expensive technology. However, they are not generally as flexible as programmable analogs or digital hearing aids for adjusting to a particular type of hearing loss or to specific hearing needs. Because the processing is less sophisticated, these aids may be less effective in difficult listening environments.
• Programmable analogs have the same analog circuitry, but they can be digitally programmed on a computer to permit a variety of settings for different types of hearing loss and hearing needs. The hearing aid dispenser programs the settings and later fine-tunes them to the specific hearing loss and changes in hearing. Some of these hearing aids will have multiple programs. This may allow the wearer to adjust them to a particular situation with a remote control or by pushing a small button on the hearing aid. Many programmable analog devices offer more flexibility than basic analog aids, having more adjustments for the amplification of soft sounds without overamplifying loud sounds. Those with multiple programs allow the wearer to adjust the response of the hearing aid to different listening situations. The only disadvantage seems to be the cost as they are more expensive than the basic unit; but, on the other hand, they are more versatile.
• Digital hearing aids amplify sound by means of a computer chip rather than conventional analog circuitry. This type of aid converts incoming sound into digital code, then analyzes and adjusts the sound based on the user’s hearing loss and listening needs. This information is stored in a computer program within the device. Signals are converted back into sound waves and delivered to the ears. The result is that sound is more finely tuned to the type of hearing loss. Digital is the most advanced and versatile technology available in hearing aids. Some digital aids may have added features that perform better in noisy situations than analog devices. Because of this, it is the most expensive circuitry on the market today and may be more than what the average person needs. For instance, when using a cell phone, more static or interference may be experienced than with other types of hearing aids. As a result, more cell phone manufacturers and makers of hearing aids are working to resolve this problem.

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 wax-like 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:

• volume control;
• a battery supplies power to make the hearing aid work;
• a microphone, which picks up sounds, converts them into electrical energy (signals) and delivers them to the amplifier;
• the amplifier, which boosts the amount of electrical energy coming from the microphone and may alter it in specified ways, depending on your hearing loss;
• a loudspeaker, which changes the electrical signals back into sound waves and channels them into the ear.

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. Similar 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:

• Directional microphones: Most hearing aids are equipped with an omnidirectional microphone which picks up sounds from the sides, behind, and in front of the wearer. A directional microphone picks up and amplifies the sound directly in front moreso than it does from other directions. This can improve understanding in private conversations held in noisy environments. A hearing aid may have a microphone with two sound inlets or have multiple microphones. Either arrangement may allow the ability to switch between directional and omnidirectional modes. All but the CIC aid can have this feature added.
• Telecoils: Many BTE hearing aids, and some ITE and ITC aids, contain a built-in telecoil circuit that can be activated by a switch or button on the hearing aid. Telecoils relay a voice on the telephone receiver using an electromagnetic signal rather than using an acoustic signal, which can cause feedback with some hearing aids. Telecoils also interface with a variety of assistive listening devices but they may not work with cell phones.
• Audio-input options: An input jack on a hearing aid allows a person to connect a wire directly to a television, stereo, separate microphone, or other assitive listening device.
• Ear-level FM systems: FM listening devices are particularly helpful for overcoming the effects of noise, reverberation, and distance from a speaker. Some BTE hearing aids combine the circuitry and an FM receiver within the same case. The FM receiver responds to the signal from a specially designed, hand-held FM transmitter.

Tips for Buying a Hearing Aid

• With all of the options available, more than one feature could work but may prove unsatisfactory when first tried. Inquire about trying out different types.
• Do not assume the latest, most expensive model is best for you. A less expensive model might improve the hearing just as much as other types.
• Be cautious of ‘free’ consultations and dispensers who sell only one brand of hearing aid. Look for a dispenser who deals with several manufacturers so that there will be plenty of options available.
• Be alert to misleading claims and manufacturers who say their hearing aids can eliminate background noise. Some aids can make hearing in noisy places more comfortable, but no aid can filter out one voice from other voices in a crowded room.
• Ask what the cost of the aid includes. Most dispensers bundle into a single fee the cost of the hearing aid and such other related costs,as those for a certain number of follow-up visits, the warranty, and one pack of batteries.
• Be sure to obtain the terms of the adjustment period and warranty in writing. This should include the return policy, the exact amount to be refunded if the aid is returned, how long the warranty lasts (preferably one or two years), and specifically what is and is not covered. It should cover both parts and labor.
• During the trial period, keep a detailed list of what you like or dislike about the hearing aid and take that list with you when you return to the dispenser.
• Use only the size and type of battery recommended by the hearing aid dispenser. Most batteries are zinc-air, activated when the adhesive tab is removed or when air enters the battery. They have an excellent shelf-life, so several packages can be purchased at once. Be aware that most batteries last only a week or two.

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.

• Keep it clean and dry, wiping it with a tissue or soft cloth every time it is removed from the ear. A soft toothbrush is good to use each evening. Hearing aids should not be worn while swimming, showering, or bathing. They should also be kept away from steamy kitchens or bathrooms since moisture can not only pose a blockage problem but can provide a medium for bacterial growth.
• Check for wax in the small holes at the tip of the aid. Careful cleaning is required to unblock these holes. Consider purchasing a built-in wax guard on the hearing aid.
• Do not expose the aid to intense heat, for example, leaving it on top of a radiator or in the car.
• Store in a safe, dry, dust-free place. Purchasing a dehumidifying container will be worth having during night-time storage.
• Open the battery door when the aid is not in use. This will ensure that the aid is off and will make the batteries last longer. It also lets air in and moisture out.
• Do not drop the hearing aid. Insert it over a soft surface just in case. Never leave it in a place where it can be accidentally knocked off.
• Have the hearing aid cleaned and serviced regularly, and never repair it yourself. This can not only damage the aid but will void the warranty. If the aid breaks or malfunctions, notify your hearing aid dispenser.
• Always keep the device and the batteries away from children and pets. They can choke on them.