Hearing Aid Styles
Behind-The-Ear Hearing Aids (BTE)
This type of device sits behind the ear and attaches to a custom molded earpiece (earmold) which fits in the ear canal. Behind-the-ear aids are appropriate for all types of hearing loss and all types of circuitry are available. Some behind-the-ear aids are quite small, although those that are more powerful are typically a little larger. Contrary to what some people think, this style is not "old fashioned" and often works better for some individuals.
- Generally last longer/replace them less often
- More comfortable for some people
- Feedback problems are usually improved
- User may feel less "plugged" than with in-the-ear styles
- Most can be more easily adjusted for different losses or for changes in hearing levels
- Come in different colors -- gray and dark brown to match hair color, or for children (or adventurous adults), they are available in bright colors
- Usually required for more severe to profound hearing loss
- Earmold takes more of the "wear and tear" and can be easily cleaned when necessary
- More susceptible to moisture and perspiration, which can cause more repairs to be needed
- Some individuals find them uncomfortable with glasses
- They can be more complicated to insert and adjust for new users, as there are two parts to deal with
- They are more visible than the smaller, in-the-ear styles
- Because the microphone is so exposed, wind noise can be a problem
- The earmold and attached tubing require replacement periodically
Open-Fit Hearing Aids/Very Small Behind-The-Ear with Slim Tubes
Open-fit refers to a style of hearing aids that are worn on top of the ear with a thin tube coming from the hearing aid and going inside the user's ear canal. They are quite small (much smaller than even a regular small-size behind-the-ear aid and are cosmetically appealing since they are not easily seen. Not every loss can be accommodated with this type of aid, and they are most appropriate for mild to moderate losses, especially high-frequency losses. However, this product continues to evolve due to its popularity and relative comfort.
- Small, cosmetically appealing, lightweight and comfortable
- Good for mild to moderate, high frequency loss
- New users are often more motivated to try these
- Small battery size so low battery life
- Most often cannot have features like volume controls, memory buttons, telephone coils (this is slowly changing and some have remote control capability so features can be addressed)
- Because they are small, users with limited dexterity or vision problems can fine them less easy to handle
In-The-Ear Hearing Aids (ITE)
These devices do just what their name implies--they rest entirely within the ear canal and outer ear. In-the-ear devices are offered in a variety of sizes which are outlined below. Generally, they are most appropriate for mild to moderate losses, but can be used for severe hearing loss as long as feedback (whistling) is not a problem. Profound hearing losses almost always require a behind-the-ear aid. For a long time, about 75% of all hearing aids sold were the in-the-ear style. This has now changed with the popularity of the small, open-fit-type BTE’s. Currently the ratio is about 60% BTE and 40% ITE in terms of types of units purchased.
- Nothing going over the ear; no interference with eyeglasses
- Microphone placement funnels the sound more directly into the ear canal
- Less trouble with perspiration and moisture (your ear really doesn't "sweat")
- Only one piece to insert and manipulate
- Smaller aids are more cosmetically appealing
- There can be a "plugged" feeling, which individuals experience to varying degrees, and there may be a sensation of pressure, undesirable sound of own voice, increased loudness of chewing when eating
- More susceptible to mechanical breakdown, usually because earwax clogs the receiver opening
- Sometimes less flexibility with adjustments on the aid, especially with smaller ITE's
- Since the ear "grows" and the ear cartilage changes shape as we age, the aid may not fit as well as time passes, which makes a "recase" of the aid necessary -- a more expensive procedure than simply replacing the earmold for a BTE
Full Shell/Full Concha (ITE)
This size fits in the ear, but fills the entire "bowl" of the outer ear. It is a better choice for those with manual dexterity problems and the battery life is usually longer compared to the smaller sizes. A telephone switch can usually be added, if necessary, and for most manufacturers, there is a wider selection of circuits available so a wider range of hearing losses may be accommodated. They are quite visible, so cosmetically they may not be appealing to some users.
This style is about half the size of the full shell and only fills the ear canal and a portion of the outer bowl of the ear. Half-shells are a little larger than the in-the-canal and are a little more visible. Cosmetically, both sizes can be easily seen from the side, but often are pretty well hidden when a person is viewed from the front. Batteries are smaller and some circuits may not be available, due to the size of the instrument. Presence of feedback may require removal of the hearing aid during telephone use.
Completely In-The-Canal (CIC)
These are the "invisible" hearing aids, which are very small and fit entirely into the ear canal. There is a short removal wire, sort of like fish line, to remove the aid from the ear. Generally the volume of the aid is “fixed” to a certain level and there is no volume wheel for the user to adjust. Some of the higher technology digital/programmable aids have a program button that can be pushed to adjust the sound.
Although the device was originally developed to be cosmetically appealing to the consumer, there are acoustic or "hearing" advantages for this type of aid: less volume is needed to accommodate the loss because the aid fits down more deeply inside the ear canal; wind noise is minimized; phone use is often improved; and they work well for high frequency losses.
However, not all individuals can tolerate the deep canal fitting and people with small or unusually shaped ear canals are not good candidates for the aid. The aid is tiny, so manual dexterity is an issue and battery life is normally only about 1 week. Also, this hearing aid is very susceptible to earwax problems and this can mean frequent repairs. In the past they really only worked well for mild to moderate losses, but with the advances in digital technology and improvements in feedback control, a wider range of hearing loss can now be fit with this style. Cost is now much less based on the style or size of the hearing aid and more predicated by the level of technology.
Circuits And Technology
Hearing aids can be generally classified into two separate categories: analog or digital circuits. All manufacturers now make a variety of digital products, from basic to the most advanced technology. Analog hearing aids have all but gone away and there are a few manufacturers who no longer produce analog products at all. Digital technology products are marketed by manufacturers as having “improved” sound quality and other features that will enhance the communication ability of the listener, particularly in situations where background noise is present. Manufacturers are required by the FDA to have research to substantiate their claims, however, not all individuals will notice improved communication with more expensive, high-tech devices. Many factors influence how a hearing aid will function for any given person. These include amount and type of hearing loss, speech discrimination scores, proper fit and adjustment of the aid, motivation, age, and many others.
What does “digital” technology really mean? A digital hearing aid, just like a digital recording, breaks the incoming sound signals into millions of bits per second and then “reassembles” them before they are fed into the user’s ear. Because the digital process is happening so quickly (millions of times per second), it also enables other features and functions of the aid to be manipulated, in effort to improve the end result to the wearer. The digital process can allow for a quieter circuit, less distortion, more flexibility in programming the hearing aid, and, for many, a better sound quality. However, just because a hearing aid is digital, it does not necessarily mean the individual will hear speech more clearly. The theory is, if a better quality sound can be fed into the ear and then from there to the brain, the person will understand better. This does not always occur.
These types of instruments are available in all styles and sizes. As mentioned above, conventional/analog hearing aids are decreasing in use, and are becoming less and less available. Standard hearing aids are typically ordered with a particular circuit, which is somewhat generic and already built into the instrument. There are usually adjustment “screws” or “pots” which can be manipulated to fit the individual’s loss. A volume control is standard and the BTE aids also usually have an on-off-telephone switch.
Telephones And Hearing Aids
Hearing aids and telephones can have compatibility problems. The main issue is feedback or a whistling sound. Telephone switches are available on BTE’s and larger ITE’s. The CIC styles often work well with a phone unless the loss is severe. Other options include an amplifier which is part of the phone itself, or auxiliary amplifiers that plug into the handset. Speaker phones are another alternative. Some manufacturers offer a “boot-type” amplifier whereby a BTE hearing aid can plug into a loop amplifier or telephone booster. Some aids have Blutooth capability and can be used with Blutooth capable phones.