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New Hearing Aid Technology
 
 
 

 
New Hearing Aid Technology
 

 
New Hearing Aid Technology
 
Some new hearing aid features can be confusing because of the specialized terminology used to describe them. Different options include: programmability, multiple frequency bands, multiple listening programs, digital signal processing, and remote controls. These are available in most styles of hearing aids, including the tiny "Completely in the Canal" aids, and the powerful "Behind the Ear" aids. Just what are these features?

 
Programmability 





 
Programmability refers to the ability of your audiologist to change the parameters of your hearing aid in the office without sending it back to the factory. Some programmability has been available for a long time using potentiometers (variable resistors) built into the hearing aids. These resistors can be adjusted by screwdriver, however the number of parameters that can be adjusted is limited by the number of potentiometers that can be put in a reasonably sized hearing aid.

The programmable hearing aids getting most of the attention now are programmed by computer in your audiologist´s office. This allows many parameters to be changed, even in tiny hearing aids like the Completely in the Canal aids. Also it allows the audiologist to let you try several listening programs, and to be able to go back to the program you like best, even a long time after the first adjustment was made. These aids also allow your audiologist to adjust the sound of your hearing aid as your hearing preferences change over time.
 
Multiple Frequency Bands
 
Some hearing aids have multiple frequency (pitch) bands, with different parameters for each band. For example, your ear might find loud mid-frequency sounds more objectionable than loud high-frequency or low frequency sounds, and a three frequency band programmable aid could be adjusted to accommodate this by having different gain settings in the different bands. Each band could have its own amplification, compression limiting, or dynamic range settings. The audiologist can adjust the position (edge frequencies) of each band as well as the other characteristics of some of these aids.

A simple version of this could be an aid with two bands, one high frequency and one low frequency. The aid might have automatic volume controls set to cut the amplification in the high frequency band in the presence of loud noise without changing the amplification of the low frequency band. This would be good for many noisy situations. The industry name for this kind of circuit is "K amp" and it is available in many different brands of hearing aids.
 
Multiple listening programs
 
Some hearing aids have more than one group of settings. A simple one-program hearing aid can be set for the listening situation that bothers you the most, or perhaps the one where you spend most of your time, such as near a noisy air conditioner in your office.

Multiple-program hearing aids can be switched between programs whenever you like. For example, you might have one program for quiet conversation or music, and another for noisy situations where communication is difficult. Some hearing aids have many different programs. More programs are not necessarily better however, because switching between them and keeping track of which program you are using can be a bother. You switch between programs by pushing a button on the hearing aid or by using a remote control.
 
Remote Controls 



 
Yes, even hearing aids can have remote controls, just like your television set. The remote controls typically are about the shape of a credit card and as thick as a pencil and operate by infrared light or radio signals. The radio control units can stay in your pocket or purse while you operate them.

These remote controls typically control loudness, and listening program (such as "for noise" or "for music"). Some even have tone controls and telephone switches in them. One brand has a zoom feature that can focus the listening field to the front when you want. Most can adjust both hearing aids at the same time.
 
 
Digital Signal Processing 

 


 
 
True "digital" hearing aids are just entering the market (and are described in more detail on another page of this web site). The word "digital" has been used with hearing aid marketing for some time, but in the past it referred to the ability to program the aid "digitally", not that the aid used digital signal processing. Now, some new hearing aids do use digital signal processing to improve the signal to noise ratio and to process the sound signals. The real breakthrough was in being able to manufacture dsp chips that are able to operate on tiny hearing aid batteries for a reasonable amount of time.

 
 
The future





 
 
These features are available in hearing aids now. The first nearly invisible "Completely in the Canal" aids appeared just a couple of years ago, and now nearly all manufacturers offer them. Two manufacturers introduced digital signal processing to hearing aids about a year ago. Now three more brands offer true dsp hearing aids. You can expect hearing aids to continue to get smaller, to have more features, and to provide better hearing.

Cochlear implants, which are a form of hearing aid, are gaining wider acceptance in spite of their cost and long training requirements. A Cochlear implant is a bundle of tiny wires that is inserted surgically into the inner ear. The electrodes are connected to a processor by a transformer-like connector and magnet implanted behind the ear. The signal processor, drives the electrodes according to sounds picked up by a microphone near the ear. With training, people who have lost their hearing after first having at least some hearing early in life, can learn to interpret the stimuli as sounds and some seem to be able to hear quite well.

Hearing aids are far from perfect, and people with hearing loss cannot expect to hear as well as people with good hearing, even with the best hearing aids made. You should always try to protect your hearing, because technology cannot fix lost hearing, not now, and probably not in the future either.