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1. Is it really necessary to wear two hearing aids, or can I get by with one?
2. How much time is needed to adapt to a hearing aid?
3. Why do hearing aids cost so much?
4. How often must hearing aids be replaced?
5. How are hearing aids different from cochlear implants?
6. What are assistive listening devices (ALDs) for TV, telephones, and theaters?
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1. Is it really necessary to wear two hearing aids, or can I get by with one?
If a significant hearing loss is identified in both ears, then two (binaural) hearing aids will be recommended in order to provide maximum benefit. There are four reasons why binaural (both ears) listening is superior to monaural (one ear):
A) Improved hearing in noise: The brain is better able to process sound more effectively when the sound signals reaching the brain are the same. The process is very different when the brain receives a strong signal from one ear and a weak, incomplete signal from the other ear.
B) Improved signal vs. noise level: Noise in a room may occur from all directions and is very intense when compared to a softer speech signal coming from one direction. So, while the noise level doesn’t decrease the speech level does. Wearing two (binaural) hearing aids ensures that the speech sounds will not be diminished any more than necessary due to your position in a noisy area.
C) Improved localization ability: When there is a significant difference in hearing between the ears it becomes very difficult to locate the sound source if a person doesn’t see it. Symmetrical hearing between the ears significantly increases one’s sound awareness and improves one’s ability to localize.
D) Increased deterioration of hearing in unaided ear: We hear with our brain not with our ears. The ultimate goal with hearing aids is not to make sounds louder but to get a strong, more complete sound signal to the brain. While it is uncertain whether hearing sensitivity will decrease if your ear is not stimulating your brain adequately (due to hearing loss), research now suggests that there can be differences in the way in which your brain processes sound, when only one ear is aided.
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2. How much time is needed to adapt to a hearing aid?
While each person's experience will vary, hearing aids may allow a person to experience certain sounds they had never heard before (or at least for some time). Relearning takes place in the central auditory nervous system and not in the ear itself. Recent experiments suggest that a listener's ability to comprehend speech may continue to increase over a period of several months when wearing a new amplification system. This process is termed acclimatization. Most dispensing audiologists currently allow for a trial or adjustment period with new hearing aids. Wearing your hearing aids all day everyday for 2 – 4 weeks is usually plenty of time to acclimate to the new sounds provided by your new hearing instruments.
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3. Why do hearing aids cost so much?
The reasons hearing aids cost so much are:
A) They are sold in relatively low volume (i.e. approximately 1.7 million hearing aids for some 30 million hearing impaired) are sold per year, as compared to several million stereos.
B) The amount of time and money spent by manufacturers on research and development is considerable. One manufacturer claims to have spent over twenty million dollars developing a single model.
C) The amount of time spent by an audiologist with a patient is very significant. Data indicate that an average of five direct contact hours is spent during the first year a patient receives hearing aids. This time is critical for new users, particularly to assist during the acclimatization process. Mail order or budget clubs can afford to sell hearing aids at lower prices because the electronic components often are inexpensive and the hearing aids themselves are often placed on the user with minimal (or in the case of mail order) no instructions or fine tuning adjustments. Furthermore, the patient may be charged for every return visit, including minor tubing change and adjustments. Thus, in the long run the patient is likely to pay as much or even more. Additionally, the minimum amount of training required for a dispensing audiologist is a Masters degree while mail order or discount centers are often staffed by sales people having minimal technical training. Audiologists, like consumers, are concerned about keeping the cost of hearing aids affordable. The reality is, communication is one of the most important skills humans have. So if wearing hearing aids allows you to resume normal activities and communicate with loved ones, the cost becomes a lot more justifiable.
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4. How often must hearing aids be replaced?
Generally speaking, hearing aids should last for at least five years. The need for new hearing aids may occur if a patient's hearing status changes, but with the availability of programmable and digital hearing aids, changes can be made in the audiologist's office and should reduce the need to order new hearing aids merely because of changes in hearing status.
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5. How are hearing aids different from cochlear implants?
Hearing aids amplify sounds, which makes sounds louder. The sounds produced by even the most sophisticated hearing aids may not offer much benefit to people with severe – profound hearing loss in both ears. Quite simply, no matter how loud the sound is produced by the hearing aid, a profoundly hearing impaired ear can not process the sound information due to the damaged hair cells in the inner ear (cochlea), which caused the hearing loss.
A cochlear implant does not make sound louder; it provides useful sound information by directly stimulating the surviving auditory nerve fibers, bypassing the damaged hair cells, in the cochlea, allowing the person to perceive sound.
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6. What are Assistive Listening Devices (ALDs) for TV, telephones, and theaters?
One of the major goals of signal processing schemes is to enhance the signal to noise ratio perceived by the listener. The use of hearing aids with automatic low frequency reduction represents an attempt at this goal. Unfortunately, despite all the new technological advances, a basic problem remains for which wearable amplification falls woefully short. That problem relates to the physical distance between the microphone of the hearing aid and the source of the sound signal. Intensity (loudness) decreases as physical distance increases.
Unfortunately most background noise surrounds the listener, so while the intensity of the speech decreases with distance, the intensity of the noise may not. This is one reason why hearing aids transmit sound so well if the speaker talks directly into the microphone, but at longer, more realistic distances reception diminishes. It would be ideal to have the sound produced at the source transferred directly to the listener without losing any intensity. It is usually impractical to ask the speaker to move closer to the listener's ear. One way of achieving this effect is with direct audio input, in which the speaker holds a microphone that is hard wired to the hearing aid itself near his mouth. Many hearing aid wearers are reluctant to ask the speaker to do this.
An alternative approach is available through infrared transmission, FM transmission, or inductance loop transmission. These systems are currently used in many theaters, concert halls, houses of worship and households. One of the best uses is for television listening. The portable transmitter (usually smaller than most cable boxes) and microphone are located near the TV loudspeaker. The sound picked up by the microphone is then transmitted in the same intensity to a receiver worn by the listener. These devices can transmit with minimal distortion over a considerable distance (up to 50 feet).
ALDs are becoming increasingly common in public places, due to the legislative enactment of the Americans with Disabilities Act. Other non-wearable devices that assist the hearing impaired listener include telephone amplifiers, vibrating alarm clocks, TV closed caption decoders, inexpensive personal hand held or body borne amplifiers, visual alarm systems, and TDDs (telephone devices for the deaf).
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