About Hearing
FAQ'S
Frequently Asked Questions About Hearing Aids- How do I determine if I am a candidate for a hearing aid?
- Is it really necessary to wear two hearing aids, or can I get by with one?
- Why does my voice sound so odd to me when wearing hearing aids?
- What are digitally programmable hearing aids?
- What are multi-channel (multiband) hearing aids?
- How are directional and multiple microphones used?
- What about the new digital hearing aids?
- How much time is needed to adapt to a hearing aid?
- Why do hearing aids cost so much?
- How often must hearing aids be replaced?
- What are assistive listening devices (ALDs) for TV, telephones, and theaters?
- What should users of new hearing aids realistically expect?
- What do you recommend for good daily care and cleaning of ears for both children & adults?
- Can loud music cause damage to a young child's ears?
- Is too little or too much earwax something to be concerned about?
- Why do I feel pain in my ears when I have a sinus infection?
- At times I notice a sense of fullness, or popping and cracking in my ear. What makes my ear feel this way?
- How can I tell if my teenagers' hearing is damaged?
- What can I do to prevent swimmer's ear in the first place and keep it from becoming an ear infection?
- At what age should I begin regular hearing check-ups and how often should I get them?
How do I determine if I am a candidate for a hearing aid?
The critical variable is whether you experience difficulty hearing or are having increased stress and strain in your daily function. Amplification may simply relieve the strain of hearing, as opposed to making sounds louder or even improving your understanding of speech. However, this alone can be a very significant benefit. You must ask yourself whether you find you are becoming stressed or fatigued after a day of straining to listen. Ask yourself whether the ability to hear, but not understand, is adequate for your needs. Unselfishly examine whether you are becoming a burden to your family and friends, even if you do not personally recognize difficulty hearing. Remember that wearing a hearing aid is not necessarily a mark of infirmary; rather it is a mark of courtesy to others. Thus, sometimes it is advisable to arrange to try hearing aids within your own unique environments to determine whether the benefit warrants the expense.
Is it really necessary to wear two hearing aids, or can I get by with one?
There are four main reasons why binaural (two eared) listening is superior to monaural (one eared) listening.
They are:
- Better Hearing in Noise: An individual's hearing in noise can be improved if the signal reaching each ear arrives at a slightly different moment in time. This is technically referred to as phase. When the brain receives slightly different, yet still audible signals at the two ears, it has the ability to cross-correlate and process the primary signal (usually speech) better than if the signal is received monaurally.
- Improved Signal versus Noise Level from Optimizing Position: Sound loses intensity (loudness) when it travels across the head. This occurs mostly for the high frequencies which are the most important for understanding of consonants, such as /s/, /t/, /f/, and /sh/. If you have a hearing aid on only one ear, say the left one; and the person you wish to hear is speaking to you from the right side, the consonants may be decreased by nearly 20 decibels by the time it gets to your aided ear. Unfortunately, noise in the room may occur from any or all directions, so while the noise level is not decreased, the speech level is. Wearing two hearing aids ensures that the speech sounds will not be diminished any more than necessary because of your position in the room.
- Improved Localization Ability: We determine where a sound is coming from on the basis of 1) the relative time in which the sound arrives at each ear, 2) the relative difference in loudness at the two ears, and 3) the relative difference in the pitch of the sound at the two ears. When there is a large difference in hearing between two ears (as might occur when a person with similar hearing in both ears only wears one hearing aid) the brain cannot make use of these subtle relative differences and their ability to locate sounds may suffer.
- Possible Deterioration of the Unaided Ear: We hear in our brain, not in our ears. The ultimate goal of hearing aids is not just to send sound into the ear. It is also essential to retrain the central auditory system in the brain. While it is uncertain whether hearing sensitivity (ability to hear soft sounds) will decrease if your ear is not stimulated adequately, research now suggests that there can be changes in the way in which your brain processes sound when it is "starved." Thus, providing stimulation may be important in preserving your auditory potential.
There are four primary styles of modern hearing aids. They are: Behind-The- Ear (BTE); In-The-Ear (ITE), In-The-Canal (ITC), and Completely-In-The-Canal (CIC).
While many people choose style based on vanity, decisions regarding which style of hearing aids are most appropriate for you may need to be based on a variety of factors.
Physical factors include: The shape of your outer ear: deformed outer ears may not allow for wearing of BTE styles. The depth of the depression near the ear canal (technically called the concha): if your ears are very shallow there may not be adequate space for certain ITE model aids. The ear canal size and shape: certain ear canals may be too narrow or shaped in a manner such that ITC or CIC hearing aids will either not go in easily, or may fall out too easily. Manual dexterity: not only is the removal and insertion of canal style hearing aids difficult for some people, but some individuals are unable to insert the battery or manipulate the volume control. Wax in the ear: some people build up large amounts of earwax, or may have extremely moist ear canals that require adequate ventilation. For these people ITC, or even certain full size ITE aids may not be appropriate. Draining ears or ears otherwise having medical problems may not be able to safely utilize hearing aids that completely block the ear canal. For these ears, it is vital to allow ventilation so hearing aids that do not fully block the ear may be required. Sometimes, BTEs that are connected to ear moulds that have large vents (openings to let air pass through) are useful. Hearing related factors include:
- The shape of the audiogram (hearing test); individuals who have hearing loss for certain pitches (frequencies) but not others, (for example those who hear the low frequencies fine, but have a high frequency hearing loss) may be better served by systems that do not fully block the ear canal, such as an open ear fit.
- Degree of loss; currently, severe and profound hearing losses are best served by BTE style aids. This style may also minimize the likelihood of feedback (whistling).
- The need for special features such as directional or multiple microphones and/or the use of a telecoil (a small magnetic loop contained in the hearing aid that allows for better use with telephones or assistive listening devices), may dictate the preferred style.
- Acoustic feedback (whistling) occurs when the microphone is close to the loudspeaker. BTE aids have a clear advantage over the smaller ITE or ITC aids because feedback is less likely to occur. While you may feel that you will only wear an inconspicuous device, check the appearance of a small or mini-BTE aid coupled to the ear with an open ear mould. A mini-BTE aid connected to the ear with an open ear mould may be less conspicuous than most ITE and many ITC aids. Most importantly, discuss the pros and cons of different styles with your audiologist.
Why does my voice sound so odd to me when wearing hearing aids?
Some hearing aid users report that they feel as if they are in a barrel or experiencing an echo when talking. This is called "the occlusion effect." Normally, when your ear is unblocked and you are speaking, you hear yourself both through the air traveling through your ear canal, (air conduction) and through vibrations that you create in your skull and ear canal (bone conduction). When your ear is occluded or blocked, however, air conduction transmission is reduced and bone conduction perception enhanced. Try this experiment. Hum aloud and then alternately plug and unplug one ear while humming. Notice how the sound changes pitch and loudness in your plugged ear? This happens because the vibrations are blocked from their usual escape route. Most new users adapt to this effect and it isn't a problem. However for some, the following steps might help: Keeping the ear as open as possible. Reducing the amount of gain (amplified volume) in the low frequencies. Using an ear mould that fits very deeply into the ear canal so that it contacts with the bony rather than the soft cartilaginous portion (to reduce vibration). What can I do about the whistling (feedback) produced by hearing aids?
There are two types of acoustic feedback: that produced internally from the hearing aid - indicating a device in need of repair; and the more common external feedback produced by a leakage of amplified sound out of the ear canal and back into the microphone of the hearing aid. Feedback that occurs when the hearing aid is being inserted or removed or when your hand is cupped near the device is common, and does not necessarily signal the need for action. If however, you experience feedback when you speak, chew, yawn or change position, you need to consult your audiologist. Feedback is more likely to occur in smaller hearing devices because the microphone is closer to the area at which the sound comes out into the ear. So, a behind-the-ear style may be less likely to produce feedback than in in-the-canal style device. Usually, external feedback can be corrected by:
- properly reinserting the hearing aid or ear mould remaking the ear mould (or in-the-ear shell)
- plugging, or reducing the diameter of any vents (holes)
- reducing the amount of high frequency gain, (typically an unacceptable trade-off because of the resultant loss of high frequency hearing)
- altering the sound by means of filters in the hearing aids or changes in the way the devices are programmed
- adding a "canal lock" (a piece of plastic) to better hold canal hearing aids in place so they don't work their way out of the ear canal as you chew
- Recently some manufacturers have introduced digital feedback reduction. With this technology, feedback is sensed by the hearing aid and cancelled by means of a new signal generated by the hearing aid itself.
What are digitally programmable hearing aids?
Some of the characteristics of the sound produced by hearing aids can be modified using computers or other devices. Hearing aids that have this capability are called "digitally programmable."
They have several advantages over non-programmable instruments.
What are multi-channel (multiband) hearing aids?
Now that audiologists have a better understanding of the importance of providing adequate gain without exceeding the physical saturation limit of the aid and the individual's loudness discomfort level at each frequency, the accurate measurement of these features have become an essential part of the fitting process. As a result of these enhanced procedures, it has become abundantly clear that significant differences exist not only among individuals with nearly identical audiograms, but also among the loudness growth of specific frequencies for a given individual. In other words, a patient can demonstrate loudness tolerance problems for certain frequencies, but not for others. Therefore, the electro-acoustic characteristics programmed into the hearing aid should differ for the various frequencies. Through the use of multiple compression channels (some systems have two, some have three) a completely unique set of signal processing instructions can be utilized. As such, a certain acoustic environment can trigger a response which, for example, produces additional high frequency boost while simultaneously reducing low frequency gain.
In addition, hearing aids containing single channel compression unfairly penalize certain sounds. For example, if a low frequency noise exceeds a certain level, compression (a reduction in gain) will occur for ALL frequencies, not just the offending ones. With multi-band compression, the reduction in gain is limited to those frequencies containing the offending signal. This may be the most important advantage of all.
How are directional and multiple microphones used?
Most of the time, listeners are facing the person they are speaking to. Noise, however, is often located in front of, behind, and/or to the sides of the listener. Some hearing aids now contain directional or multiple microphones which "communicate" with each other in a manner such that sounds originating from the front of the hearing aid receive maximum amplification and sounds originating to the sides or behind the hearing aid receive considerably less amplification. This effectively suppresses some of the annoying background noise that creates so much difficulty for hearing impaired listeners. The technology using these types of microphone arrangements is very promising. They can be found in several different hearing aids but are generally limited to behind-the-ear or full shell in-the-ear hearing aids due to size restrictions.
What about the new digital hearing aids?
The future of hearing aid technology has arrived! Advancements in the ability to manufacture hearing aids that process sound digitally offer the potential for dramatic improvements over previously available instruments. Hearing aid researchers have been investigating the use of true digital technology for over a decade but were held back because the increased power consumption needed to operate such instruments required the instruments to either be very large, or to be connected to a separate power source worn on the body. As a compromise, digitally programmable hearing aids were introduced on the market about six years ago. These devices represented an improvement over previous technology in that they were extremely flexible, could be fine-tuned, and had advanced compression (loudness limiting) capabilities. They were still somewhat limited, however, because even though they were programmed by a computer (the digital portion) they still operated in an analogue fashion. This meant that sound entering the hearing aid microphone would be amplified and filtered by a variety of electronic components. Because hearing is such a complex sense, the extent of filtering and amplifying required to partially correct impairment added to the limitations of the hearing instrument by producing distortion and noise.
Digitization means that incoming sounds are converted to numbers, which are then analyzed and manipulated via a set of rules (algorithms) programmed into the chip controlling the hearing aid. There are now nearly a dozen digital hearing devices available. Some of these digital aids analyze incoming sound; make a determination regarding speech versus noise content, then convert this information to numbers. The resultant digitized numbers are then manipulated according to algorithm instructions, reconverted to an analogue form (sound waves) and delivered to the ears without producing the types of distortion that were often associated with analogue technology hearing aids.
Why do hearing aids amplify so much noise and make sounds too loud, but not clear enough?
Among the most frequent complaints voiced by hearing aid users are that noise is amplified too much and that certain sounds become too loud for the user to bear. Some modern hearing aids contain sensors that allow the hearing aid to detect sounds exceeding a certain loudness level, and then self-adjust to reduce the amplification (gain) for those sounds. Unfortunately, because noise is comprised of many of the same frequencies as speech, it is virtually impossible to "shut out" noise without also adversely affecting the quality of the speech signal. The good news is that audiologists have learned to utilize modern technology to measure and control the maximum sound intensity reaching your ear. If sounds (speech or noise) exceed either the saturation level (maximum level the hearing aid can amplify without distortion) or your personal loudness discomfort level, distortion or discomfort will be the result. Modern hearing aids utilize technology that allows for adequate gain for soft sounds while minimally (or not at all) amplifying loud input signals.
Concerning background noise, new techniques using multiple microphones within the same hearing aid are improving the listener's ability to function in noisy environments. With regard to clarity, even the most sophisticated hearing aids' ability to clarify speech is limited by the degree of inner ear and/or central auditory nervous system distortion.
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.
Why do hearing aids cost so much?
The reasons hearing aids cost so much are: 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. 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. 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. Furthermore, the patient may be charged for every return visit, including minor tubing change and adjustments.
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.
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.
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 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 desired to be heard. 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 theatres, 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).
What should users of new hearing aids realistically expect?
When wearing hearing aids:
- Your hearing in quiet environments (one to one communication watching TV, etc) should be improved.
- Your hearing in moderate background noise should be improved.
- Your hearing in background noise is NOT going to be as good as your hearing in quiet.
- Your hearing in loud background noise should be NO WORSE than without the hearing aids.
- Soft speech should be audible, average speech should be comfortable; loud speech should be loud, but never uncomfortable.
- Your ear moulds should be comfortable.
- Your own voice should be "acceptable" to you.
- There should be no feedback when the hearing aids are properly seated in your ears.
- You may hear sounds you have not heard for a while (like footsteps or the refrigerator humming). This is not abnormal.
Hearing aids WILL NOT restore your hearing capabilities to "normal" or to pre-existing levels.
What do you recommend for good daily care and cleaning of ears for both children and adults? For the most part, daily care of the ears is unnecessary for both children and adults. Ear wax production is normal for all children and adults and is usually not a problem unless it occludes the ear canal causing hearing loss. Most ENT's prefer their patients not to use cotton�tipped ear-buds because of how easily ear trauma can occur. Ear-buds can also further compact wax in the ear canal.
Recently, I attended a wedding reception with a very loud band. The music was uncomfortably loud and gave me pain in my ears. After 30 minutes I had ringing in my ears. My concern was for a two-year-old boy whose mother had him dancing right in front of the band. Wouldn't music that loud cause damage to a young child's ears? Mine were still ringing a day later. Loud noises can cause hearing loss. Sometimes the loss is of short duration (say after a concert) and is called a temporary threshold shift. On occasion the loss is long-term and irreversible and is called a permanent threshold shift. The degree of hearing loss depends on both the duration and intensity of the noise. Very loud noises (over 100 decibels) can cause hearing loss even with very short exposure (approximately one hour). We are all exposed to noises (power tools, music headphones, power lawnmowers, etc.) that prior generations were not exposed to. It is important that we remain conscious of the harmful effects of noise on our hearing and do what we can to protect ourselves from extreme noise exposure.
When my husband turned 58 his ears quit making earwax completely, even though he previously had an abundance of earwax. Is too little or too much earwax something to be concerned about? Production of ear wax varies among individuals. Wax is a normal part of the makeup of the ear canal, having some positive properties including inhibition of bacterial growth as well as being water repellant. Wax consists of a variety of substances including wax from cerumen glands in the ear canal and skin that turns over (exfoliates) from the skin of the ear canal. An abundance of wax is problematic only if the canal is blocked and causes hearing loss. A lack of wax, for the most part, also poses little problem.
Why do I feel pain in my ears when I have a sinus infection? It is not uncommon to have pain in the ears from sinusitis without actually having an ear infection. Pain in the ears, termed otalgia, is common with a variety of head and neck disorders including sinusitis, laryngitis and pharyngitis (sore throat). The pain felt in the ears is actually transmitted via nerve connections from the sinuses to the ears and is called referred pain or referred otalgia. Otalgia should always be investigated as it may represent underlying disease in other areas of the head and neck.
At times I notice a sense of fullness, or popping and cracking in my ear. It is intermittent throughout the year, but more prevalent in the spring and autumn and when I fly. What makes my ear feel this way? Rapid changes in pressure, such as an airplane ascending or descending, as well as a cold or allergies, can cause this sensation of fullness. Usually the Eustachian tube, a canal connecting the back of the nose to the middle ear, regulates ear pressure so both sides of the ear drum are equal. With colds and allergies, however, membranes in the nose become swollen, and may block the opening to the Eustachian tube, resulting in that stuffy-ear sensation. The rapid changes that occur in air pressure when a plane ascends or descends, or when one scuba dives, also sometimes impair the Eustachian tube's ability to equalize. There are some simple measures to help reduce these sensations. When flying, chew gum during take off and landing or try swallowing, yawning or any other exercise that helps the muscle connected to Eustachian tube expand and contract. Pilots and some seasoned air travellers take over-the-counter decongestants that contain pseudoephedrine to prevent such occurrences or use nasal spray to help mitigate the effects of flying. Always check with your doctor before trying any medication.
My teenagers love to play their music loud - so loud I can feel the vibrations and I have to shout at them to be heard. I fear this exposure to noise will harm their hearing, if not now, then in the future. How can I tell if my teenagers' hearing is damaged? Many everyday items - like a car stereo's subwoofers or the headphones of an MP3 player or personal satellite radio - could indeed pose a threat to your children's hearing health if the volume is inordinately high. Repeated, long-term exposure to loud sounds (anything measuring 85 decibels and beyond), may permanently damage the tiny hair cells and nerves needed for hearing. When this occurs, it is called Noise-Induced Hearing Loss (NIHL). We may see an increase in NIHL in the coming years due to the proliferation of personal listening devices capable of producing ear-splitting volumes above 110 decibels. If you're struggling to know when loud is too loud for earphones, stand next to your children while they are using them. If you can hear the song's lyrics, the volume is too high and may cause hearing loss. After playing the stereo or listening to headphones, ask your teens if they experience any ringing in the ears (tinnitus) or a sensation of "fullness." If so, it could be a sign of temporary hearing loss, which could become permanent with repeated exposure, so you should schedule an appointment with an audiologist or an ear nose and throat doctor. These medical professionals can gauge whether or not hearing loss has occurred and, if so, the extent of the damage.
My child spends hours in the pool every day. Sometimes at night she complains of an earache. What can I do to prevent swimmer's ear in the first place and keep it from becoming an ear infection? Swimmer's ear is a common problem that is fairly easy to prevent and treat. It comes in two forms - the acute, painful variety and the chronic, itchy plugged-up-ear type. Both forms are caused by the ear canal being constantly wet. The moisture makes the skin in the canal swell a bit and lose its ability to repel bacteria. Acute swimmer's ear is painful as the skin is thin and tightly stretched to the canal bone. The chronic form is characterized by cheesy debris that plugs the ear canal. The key to treatment is cleaning the ear canal. Ear doctors use suction and curettes to quickly rid ears of debris. Beware of cotton swabs; they push the debris deeper into the canal. Once cleaned, prescription antibiotic eardrops quickly clear up the infection. Prevention is important. Avoid the old-fashioned alcohol and vinegar drops because alcohol burns and affects wax formation. (Wax is desirable because it repels water and protects the skin.)
I'm 45 years old. My wife teases me about having a selective hearing loss but I am starting to wonder if I might have real hearing loss. At what age should I begin regular hearing check-ups and how often should I get them? Listening and hearing are related but different. For a message to be "heard" the brain has to pay attention to it, which becomes more difficult as we get older. At age 45, the average person has no significant age-related hearing problems with either the ears or the brain. However, a 45-year-old who has worked 20 years in hazardous noise may, in fact, have a substantial amount of hearing loss. One easy way to determine if a hearing examination is needed is to have a conversation with your wife without distractions (TV, background talking, etc.). If her softly spoken (not whispered) message is not completely understood, it is time for an examination. Hearing loss often develops gradually and so slowly that one adapts to the change in perception without even noticing. However, once hearing loss crosses the threshold of 40-decibel hearing loss (dB HL), the effect on normal communication is very noticeable. Between 25-dB HL (the upper limit of normal hearing) and 40-dB HL, hearing may indeed seem selective because some words are easier to understand than others.
