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.
Hearing Aid Styles
What determines the style of hearing aids I should wear?
Hearing aids are available in four major styles. hearing aids.
Behind-The-Ear (BTE) (left) houses the components of the hearing aid in a small case fitting over the ear. The hearing aid is held in place by a custom earmold and clear tubing connected to the hearing aid to send sound from the hearing aids to the ear canal.
In-The-Ear (ITE) (second from left) is a custom-made instrument that fits entirely in the ear.
In-The-Canal (ITC) (third from left) is a custom-made instrument that fits within the ear canal.
Completely-In-The-Canal (CIC) (right) is a custom-made instrument that fits down deep into the ear canal and is the least visible of all the hearing aid styles.
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 earmolds 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.
- 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 earmold. A mini-BTE aid connected to the ear with an open earmold may be less conspicuous than most ITE and many ITC aids. Most importantly, discuss the pros and cons of different styles with your audiologist.
Provided courtesy of the American Academy of Audiology.
For more information Please contact:
American Academy of Audiology
11730 Plaza America Drive
Reston, VA 20190-4798