Hearing Aid Technology
In this page we will talk about:
How Hearing Aids Work
All hearing aids, whether analog or digital, are designed to increase the loudness of sounds reaching the ear drum so that the hearing-impaired person can better understand speech. To accomplish this, hearing aids require three basic components:
- A microphone to gather sound waves in the air and convert them from acoustic energy into electrical energy.
- An amplifier to increase the strength of the electrical energy.
- A receiver, which is like a miniature speaker, that converts the electrical energy back into acoustic energy (sound waves).
What differentiates hearing aids are two main factors:
- Should you choose Digital or Analog?
- Should you choose Conventional or Programmable?
Digital and Analog Differences
Analog Hearing Aids
Analog hearing instruments amplify the continuous sound wave by
simply making it larger. There are two subcategories of analog hearing
instruments: conventional and programmable.
Digital Hearing Aids
Digital hearing instruments take the continuous sound wave and break it
up into very small, discrete bits of information. This is called
digitizing the signal and all digital hearing instruments do this. The
very fact that a hearing device is digital does not make it better than
a comparable analog device. Beyond just digitizing the sound prior to
amplification, there are differences in exactly how various digital
hearing devices amplify or process sound. The more sophisticated
digital hearing instruments are able to amplify the softest sounds of
speech while at the same time subtracting out certain types of unwanted
noises. Digital signal processing allows hearing instrument designers
to write computer programs, called algorithms that can be customized to
each individual's hearing loss.
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Conventional and Programmable Hearing Aids
Conventional and
programmable hearing instruments differ in the amount and degree of
adjustments the hearing instrument dispenser can perform on the hearing
device. A programmable hearing device allows the dispenser to adjust
the amplifier more precisely to match your hearing loss. Programmable
analog hearing devices, when compared to their conventional equivalent,
provide greater fitting flexibility. This means that the dispenser can
more readily change the way a programmable analog hearing device
operates through the use of an office computer. Sometimes the added
flexibility of a programmable hearing instrument is an important
feature.
The Benefits of Digital Technology
Digital hearing instruments are truly a breakthrough in hearing technology. But how do you make sense of the many features and options? While there is never a substitute for your hearing professional's expert explanation, we have assembled this guide to help you understand some of the most common features.
The ability to manipulate the sound digitally with a microprocessor (computer) allows us to create hearing aids that offer more features and greater flexibility than analog instruments. Digital manipulation also allows each hearing instrument to be more accurately programmed for each individual hearing loss.
Cleaner Sound Quality
Digital Signal Processing (DSP) also produces a sharper, cleaner sound quality than analog processing (think about the sound quality of CDs versus audio cassettes).
Smart Hearing Aids - Background Noise Reduction
Sometimes called "smart" hearing aids, digital instruments have the
ability to process sound intelligently. They analyze the incoming
sound frequencies and volume. Based on these measurements the digital
hearing instrument automatically adjusts to help prevent unpleasant
microphone noise or ongoing background noise, such as traffic, while enhancing speech.
Channels
Channels give your hearing professional more flexibility to program your hearing instruments to your specific listening needs. The more channels a hearing instrument has, the better your hearing professional can fine-tune each sound frequency to best process sound for you.
Feedback Management
Feedback is a high-pitched whistling noise that hearing aid wearers sometimes experience. The primary purpose of feedback management is to reduce the gain (how much sound is amplified) in the frequency ranges in which the feedback is occurring. The result is a reduction of feedback while maintaining clear speech at an adequate volume level. This can be accomplished in a number of ways, depending on the type of hearing aid.
Programs/Memories
Multiple programs or memories allow your hearing professional to customize a program or memory for different listening situations. You can actually flip a switch to a program designed specifically for quiet or noisy situations, or even for talking on the phone.
Telecoil
Telecoils are special options available on some styles of hearing instruments. A telecoil helps you hear on the phone much more easily. It can also be used with assistive listening devices, such as amplified telephones and amplified television listeners.
Volume Control
Volume control helps you adapt to more listening environments. You will need different volumes of sound in a crowded theater than at home sitting across the table from a friend. Some digital hearing devices have an automatic volume control and some have a manual volume control switch.
Expansion
Expansion, which is the opposite of compression, reduces gain for very soft inputs. In other words, it reduces the microphone noise or background noises (such as the hum of a refrigerator) that can bother hearing aids wearers. Expansion can't be offered in analog hearing aids because the required circuitry is too complex.
Directional Microphones
Most hearing aid microphones are omnidirectional, which means they pick up sounds from all directions. Directional microphones, on the other hand, are more sensitive to sounds coming from the front, and reduce the sounds coming from behind (often background noise). The result in an increased signal-to-noise ratio that improves listening in noise. While directional microphones can be found on both analog and digital hearing aids, the digital advantage is that the pattern of sensitivity can change depending on the location of the noise, making digital directional technology even more effective.
Not your mother's hearing aids
Exceptional sound quality. Automatic volume adjustment. Multiple frequencies programmed to your needs. Improved hearing ability in noise situations. It's the advanced technology of 100% digital hearing aids. The power of a personal computer is channeled into a tiny microchip for a hearing aid that's so small and comfortable, many of our clients forget they're wearing them! They're the (sound) wave of the future, and they're here at Sears Hearing Centre.
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