What are hearing aids?
Hearing aids are electronic or battery-operated devices that can amplify and change sound.
- A microphone receives the sound and converts it into sound waves.
- The sound waves are then converted into electrical signals which are amplified and converted back to sound waves.
- Children as young as 2 months can be fitted with hearing aids.
Although the hearing aid can amplify sounds to achieve a "comfort level" of loudness for listening, the hearing aid can not correct for distortion of sounds caused by damage to the delicate hair cells in the inner ear or to the nerve endings which are stimulated by the hair cells. For many mild or moderate hearing losses, a hearing aid can make almost normal clarity of speech possible in a quiet room.
However, for many severe or profound hearing losses, the speech heard through a hearing aid may not be clear enough to understand completely; it may sound like a weak, distorted telephone connection. Therefore, the listener uses lip-reading or sometimes sign language to add to the understanding of speech through a hearing aid.
Although hearing aids don't provide perfect correction for hearing loss, hearing aids combined with proper training in language and listening are enormously important for communication skills for your child.
In fact, the consistent use of properly functioning hearing aids, fitted as early as possible in infancy, is the single most important factor in the development of spoken language in a hearing-impaired child.
What are the different types of hearing aids?
The type of hearing aid recommended for your child will depend on several factors that include his physical limitations, medical condition, and personal preference.
In-the-ear (ITE) hearing aids
These hearing aids come in plastic cases that fit in the outer ear. Generally used for mild to severe hearing loss, ITE hearing aids can accommodate other technical hearing devices, such as the telecoil, a mechanism used to improve sound during telephone calls. However, their small size can make it difficult to make adjustments. In addition, ITE hearing aids can be damaged by ear wax and drainage.
Behind-the-ear (BTE) hearing aids
Behind-the-ear hearing aids are worn behind the ear. This type of hearing aid, which is in a case, connects to a plastic ear mold inside the outer ear. These hearing aids are generally used for mild to severe hearing loss. However, poorly fitted BTE hearing aids can cause feedback, an annoying "whistling" sound, in the ear.
Canal aids fit directly in the ear canal and come in two styles: in-the-canal (ITC) aid and completely-in-canal (CIC) aid. Customized to fit the size and shape of your child's ear canal, canal aids are generally used for mild to moderate hearing loss. However, because of their small size, removal and adjustment may be more difficult. In addition, canal aids can be damaged by ear wax and drainage.
Generally reserved for profound hearing loss, or if the other types of hearing aids will not accommodate, body aids are attached to a belt or pocket and connected to the ear with a wire.
Is my child a candidate for hearing aids?
Probably. The type of hearing aid recommended may depend on several factors, including, but not limited to, the following:
- the shape of the outer ear (deformed ears may not accommodate behind-the-ear hearing aids)
- depth of depression near the ear canal (too shallow ears may not accommodate in-the-ear hearing aids)
- the type and severity of hearing loss
- the manual dexterity of your child to remove and insert hearing aids
- the amount of wax build-up in the ear (excessive amounts of wax or moisture may prevent use of in-the-ear hearing aids)
- ears that require drainage may not be able to use certain hearing aid models
How can I help my child adjust to her hearing aid?
- Be patient and give your child time to get used to the hearing aid and the sound it produces.
- Start in quiet surroundings and gradually build up to noisier environments.
- Experiment where and when the hearing aid works best for your child.
- Keep a record of any questions and concerns you have, and bring those to your child's follow-up examination.
What should I consider before buying a hearing aid?
The National Institute on Deafness and Other Communication Disorders recommends asking the following questions when buying hearing aids:
- Can the hearing loss be improved with medical or surgical interventions?
- Which design will work best for my child's type of hearing loss?
- May my child test the hearing aids for a certain period of time?
- How much do hearing aids cost?
- Do the hearing aids have a warranty, and does it cover maintenance and repairs?
- Can my child's audiologist make adjustments and repairs?
- Can any other assistive technological devices be used with the hearing aids?
Hearing aids typically need to be replaced after about five years. New, programmable and digital hearing aids, which can be adjusted as the level of hearing changes, may reduce the need for replacement.
What are the parts of a hearing aid?
Microphone-- changes sounds into electrical energy. Its location on the hearing aid is important, because the sounds closest to the microphone will be picked up most readily. The microphone of a body-level aid should not be covered by loose, bulky, or starched clothing, and should be protected from food or water falling onto it.
Amplifiers-- boost the electrical signal coming from the microphone. The amplifiers are located inside the hearing aid, and you will never see them, except in an aid taken apart for demonstration.
Receiver-- changes the amplified electrical signal back into sound. For a body-level hearing aid, the receiver looks like a button and snaps onto the earmold. For an ear-level (behind-the-ear or in-the-ear) hearing aid, the receiver is inside the case of the aid and is not visible.
Battery-- supplies power to the hearing aid.
Earmold-- carries the sound into the ear canal, holds the hearing aid in place, and (when properly fitted) prevents acoustic feedback or squealing by not allowing the amplified sound to get back to the microphone.
Tubing (of a behind-the-ear hearing aid) -- carries the sound from the receiver outlet through the earmold.
Cord (of a body-level hearing aid) -- carries the electrical signal from the amplifier to the receiver.
Should my child have a hearing aid for both ears?
A hearing aid with a receiver going into just one ear is called a monaural hearing aid fitting. A binaural fitting consists of separate receivers going into each ear. A binaural fitting can be accomplished by using two separate hearing aids (one for each ear) or by using a body-level hearing aid which has two microphones, one on each side of the aid, with separate receivers for the two ears. When a Y-cord is used with a body-level aid, then the input from a single microphone is amplified and fed to both ears, so that both ears receive the same
When there is some residual hearing present in each ear, two hearing aids are better than one. With only one hearing aid, it is nearly impossible to tell what direction a sound is coming from. Two hearing aids also help your child to "tune in" to one voice in a noisy room. Two hearing aids are recommended for nearly all young children with hearing impairment unless it is proven that one of the ears has no residual hearing or can not benefit from amplified sound.
Which hearing aids are best for my child?
Your audiologist will decide which model of hearing aid suits your child's hearing loss. The decision is based on several factors including the degree of loss, the slope (frequency response) of the audiogram, the possible need for future adjustments in amplification, and the size and fit of the aid on your child's ear.
Why are hearing aids so expensive?
Each hearing aid costs from several hundred dollars to over two thousand dollars. The high cost reflects the technology used to develop the miniaturized components of the aid, and the mark-up to cover the dispenser's services. If hearing aids were sold as often as calculators, the price would drop considerably; however, they are a low-volume item as markets go.
Hearing aids can be covered entirely by Medicaid if your child is eligible for a Medicaid card. For families who are not eligible for Medicaid, there is an income-dependent state program in Massachusetts to cover the cost of hearing aids. Your audiologist will tell you how to apply. A very few health insurance policies cover part of the cost of hearing aids; check with your insurance company. There are various charitable organizations to which you may apply if you cannot pay for your child's hearing aids.
How long will a hearing aid last?
Your child should be able to use her hearing aid for up to six years, although the type of aid may need to be changed sooner if your child's needs change. The hearing aid itself is not outgrown but begins to need frequent repairs as it gets older. The earmolds, however, need to be remade every few months as your child's ears grow.
If the hearing aid gets lost, look for it everywhere, and get your child to help. Most manufacturers do offer damage or loss/damage coverage for at least one year after the date of the fitting. Find out about this coverage from the vendor, and be sure to purchase separate loss/damage insurance when the manufacturer's policy runs out.
How should we take care of hearing aids?
The hearing aid is a delicate electronic instrument. These simple rules will extend its life and lessen the frequency of repairs:
- Do not leave the hearing aid on a radiator, stove, windowsill, glove compartment, car seat, dashboard of the car, or any other hot or cold place.
- Remove the hearing aid when drying your child's hair with a hair dryer.
- Keep the aid dry. Keep it out of a steamy bathroom. Take the aid off for bathing, showering, or swimming. In rain or snow, take the aid off or cover it with a hood or umbrella. If the aid gets wet, dry it immediately with a soft cloth, remove the battery, and dry it with a hair dryer on the lowest setting from a distance of two feet. If your child perspires heavily, store the aid overnight in a tightly closed container with a silica gel packet to absorb the moisture. Condensation in the tubing from perspiration or earmold washing should be blown out with an infant's nasal syringe, with the earmold and tubing detached from the aid.
- Never spray your child's hair with hair spray when the aids are being worn.
- Replace the batteries regularly.
- If there is visible corrosion on the battery contacts, take the aid to the hearing aid dispenser to be cleaned.
- Open the battery compartment of the aid or remove the batteries overnight, to prevent corrosion and improve battery life.
How can I check my child's hearing aid?
The following items are helpful for checking and maintaining a hearing aid:
- hearing aid stethocope ("stethoset") to listen to the aid (or an earmold custom-made for a parent);
- battery tester which will test batteries in the 1.3-1.5 volt range;
- baby's nasal syringe or earmold squeeze bulb
Your child's hearing aid must be checked daily, because your child may be too young to tell you when something is wrong. If you perform a systematic check of the hearing aid's function, you can find the cause of many simple malfunctions causing dead, weak, squealing, intermittent, or scratchy sound. Use a fresh battery when checking the aid.
First look at the hearing aid carefully. Is the aid turned on? Is the input selection switch on "M," not "T"?"
Are the battery contacts clean? Is the battery inserted properly and the compartment clicked shut all the way?
For a behind-the-ear aid, is the tubing free of cracks or holes? Does it fit snugly onto the aid? Is the earmold channel free of wax or moisture? Remove the tubing from the tone hook and use a squeeze bulb to blow out any moisture you see in the earmold or tubing.
For a body-level aid, look at the receiver and cord carefully. Is the insulation worn? Do both plugs fit firmly into the receiver and the aid? Is the receiver cracked or its casing loose? Is the earmold clean, and does it have a metal ring which snaps tightly to the receiver (with plastic washer if used)?
Put the aid to your ear, using an earmold or hearing aid stethoset. If the hearing aid has a volume wheel, are there any sudden jumps in loudness as you turn the volume control wheel? (The volume should increase smoothly as you turn the wheel.) Does the wheel itself turn smoothly? Is the sound scratchy as you turn the wheel, as though dust has entered the control? Leaving the volume at one level, listen for gross distortion of the sound and for the level of background noise (hum or hiss) from the aid itself.
For a body-level aid, roll the cord in your fingers at several places as you listen, to check for scratchiness or "cut-out" due to worn insulation. Wiggle the connections of the cord at each end; the sound should not cut out.
Check the source of any whistling by removing the aid and holding a thumb firmly over the canal opening of the earmold, with the aid full on. If you hear whistling, remove the tubing from the aid (for a behind-the-ear aid) or the earmold from the receiver (for a body-level aid) and now hold your thumb over the sound outlet. If there is no whistling now, the cause was a leak in the tubing or its connection (for a behind-the-ear aid) or between the earmold and receiver (for a body-level aid). If whistling persists, and the receiver is not cracked, then the aid probably has internal feedback and must be serviced by a repair facility.
- With the aid on your child and adjusted to its customary volume setting, is there feedback (squealing) as the wearer moves his head back and forth and moves his jaw? If so, and earlier steps have yielded no problems, then the earmold is too small. The wearer should be able to turn the volume up at least a little beyond the customary volume setting without feedback, so that the volume setting is never dictated by the level at which feedback occurs.