What are the different kinds of hearing aids?

There are several types of hearing aids. Each type offers different advantages, depending on its design, levels of amplification, and size. Before purchasing any hearing aid, ask whether it has a warranty that will allow you to try it out. Most manufacturers allow a 30- to 60-day trial period during which aids can be returned for a refund.

There are 7 basic styles of hearing aids for people with sensorineural hearing loss:

	Completely-in-Canal (CIC) hearing aid is largely concealed in the ear canal and is used for mild to moderately severe hearing loss. Because of their small size, canal aids may be difficult for the user to adjust and remove, and may not be able to hold additional devices, such as a telecoil. Canal aids can also be damaged by earwax and ear drainage. They are not typically recommended for children.
	In-the-Canal (ITC) hearing aid is customized to fit the size and shape of the ear canal and is used for mild or moderately severe hearing loss.
	In-the-Ear (ITE) hearing aids fit completely in the outer ear and are used for mild to severe hearing loss. The case, which holds the components, is made of hard plastic. ITE aids can accommodate added technical mechanisms such as a telecoil, a small magnetic coil contained in the hearing aid that improves sound transmission during telephone calls. ITE aids can be damaged by earwax and ear drainage, and their small size can cause adjustment problems and feedback. They are not usually worn by children because the casings need to be replaced as the ear grows.
	On the Ear (OTE) hearing aid is lightweight with a micro-tube and tiny earbud for ultimate discretion.  Appropriate for mild to moderately-high frequency hearing loss
	Behind-the-Ear (BTE). Zon is the best receiver product available on the market today with its best-in-class features optimized by BluWave Signal   Processing and backed with a lifetime circuit warranty that is waterproof.
	Mini (BTE) is the smallest BTE model available.  the model comes with thin tubing and tiny earbus for ultimate discretion.  Appropriate for most types of hearing loss and ages.
	Behind-the-Ear (BTE) hearing aids are worn behind the ear and are connected to a plastic earmold that fits inside the outer ear. The components are held in a case behind the ear. Sound travels through the earmold into the ear. BTE aids are used by people of all ages for mild to profound hearing loss. Poorly fitting BTE earmolds may cause feedback, a whistle sound caused by the fit of the hearing aid or by buildup of earwax or fluid.

Destiny Hearing Aids

The smartest hearing science

Only Destiny has BluWave Signal Processing, Starkey’s proprietary system designed to optimize noise management, feedback and whistling cancellation and talking on the phone with no trouble. The Destiny series includes multiple technology levels. Each comes with our best-in-class Active Feedback Intercept, which virtually eliminates the nuisance of feedback. Your hearing care professional will help determine the levels of environmental adaptation and directional capabilities you need. The Destiny 1600 is our most automatic hearing instrument on the market today, featuring touchless operation and a host of advanced technology benefits, including Self Check, Voice Indicators, and Follow-Up Reminder.

 

Destiny Features

		Active Feedback Intercept (AFI)* The most effective feedback cancellation system on the market today. AFI uses an entirely new method that effectively erases whistling, squealing, and other irritating feedback sounds.
		Directional Speech Detector (DSD) Standard on behind-the-ear styles and optional on many others, DSD offers superb directionality by focusing on speech sounds and reducing background noise. This technology continuously monitors environments and adjusts accordingly.
		Automatic Telephone Response Anyone who wears hearing aids knows telephone conversations can sometime be difficult. With Automatic Telephone Response, Destiny virtually eliminates feedback while automatically adjusting for optimal communication on the telephone
		Acoustic Signature A state-of-the-art sound management tool available on the 1200 and 1600 series. This system detects and classifies different sound environments, then adapts automatically to an optimal setting. Move from crowded restaurant to taxi to home, without ever making a manual adjustment
		Smart Style Our commitment to making Destiny not only comfortable, clear and supremely effective, but attractive as well. Our Destiny BTE, mini and OTE come in a range of sleek colors designed to match your hair color, skin tone, or lifestyle. And our range of styles and sizes means you can find an option that looks and feels natural on you
Destiny also offers a full package of SMART FEATURES , including:
		Voice Indicators The option of using speech, with male or female voices, to alert you to low battery, memory, as well as others
		Self Check Simply opening and closing the battery door three times runs a diagnostic check of the microphone, circuit and receiver
		Reminder To help remind you of maintenance and return visits, we've included an audible follow-up reminder.

Zon Hearing Aids

Good looks are only the beginning.

The perfect marriage of cutting-edgetechnology and exquisite design, Zon is the only hearing solution on the market positioned to offer it all: extraordinary beauty, ultimate comfort, and best-inclass performance.

What makes Zon so supremely unique?

It’s the only hearing instrument available with BluWave Signal Processing, Starkey’s proprietary system designed to optimize Zon’s already best-in-class features. So now when noise levels change as you move through different environments, your hearing aid changes with them. Unwanted whistling, otherwise known as feedback, virtually does not happen. And talking on the phone can be effortless and more enjoyable, since Zon automatically adjusts upon detecting a phone signal.

By any measure, Zon is the most advanced hearing solution on the market today. Designed to be as pleasing to the eye as it is to the ear, it provides the most natural hearing experience modern science has to offer.

 

Zon Features

		Active Feedback Intercept (AFI)* The biggest problem hearing aid wearers experience is that annoying whistling called feedback. The most effective feedback cancellation system on the market today. AFI uses an entirely new method that effectively erases whistling, squealing, and other irritating feedback sounds.
		Directional Speech Detector (DSD) Chances are you can hear the voices that are directly in front of you when in quiet situations, but have trouble when the noise level increases, like while in a restaurant with family and friends. With this common complaint in mind, Zōn was designed to include technology called Directional Speech Detector, resulting in extraordinary directional performance and better understanding in noise.
		Automatic Telephone Response Anyone who wears hearing aids knows telephone conversations can sometime be difficult. With Automatic Telephone Response, Destiny virtually eliminates feedback while automatically adjusting for optimal communication on the telephone
		Acoustic Signature With Acoustic Signature, patients experience a brand-new kind of environmental management. Because Starkey hearing solutions immediately identify and classify the statistical properties of different sound environments, switching is completely seamless.
		Elegant Design With its curved, elegant shape, cool finish, and sophisticated hair and skin-tone color palette, Zōn is the first hearing aid ever to bring together world-class technology and strikingly beautiful design.
ZON also offers a full package of SMART FEATURES , including:
		Voice Indicators The option of using speech, with male or female voices, to alert you to low battery, memory, as well as others
		Self Check Simply opening and closing the battery door three times runs a diagnostic check of the microphone, circuit and receiver
		Reminder To help remind you of maintenance and return visits, we've included an audible follow-up reminder.

Body Aids are used by people with profound hearing loss. The aid is attached to a belt or a pocket and connected to the ear by a wire. Because of its large size, it is able to incorporate many signal processing options, but it is usually used only when other types of aids cannot be used.

Do all hearing aids work the same way?

The inside mechanisms of hearing aids vary among devices, even if they are the same style. Three types of circuitry, or electronics, are used:

• Analog/Adjustable: The audiologist determines the volume and other specifications you need in your hearing aid, and then a laboratory builds the aid to meet those specifications. The audiologist retains some flexibility to make adjustments. This type of circuitry is generally the least expensive.
• Analog/Programmable: The audiologist uses a computer to program your hearing aid. The circuitry of analog/programmable hearing aids will accommodate more than one program or setting. If the aid is equipped with a remote control device, the wearer can change the program to accommodate a given listening environment. Analog/programmable circuitry can be used in all types of hearing aids.
• Digital/Programmable: The audiologist programs the hearing aid with a computer and can adjust the sound quality and response time on an individual basis. Digital hearing aids use a microphone, receiver, battery, and computer chip. Digital circuitry provides the most flexibility for the audiologist to make adjustments for the hearing aid. Digital circuitry can be used in all types of hearing aids and is typically the most expensive.

What can I expect from my hearing aids?

Using hearing aids successfully takes time and patience. Hearing aids will not restore normal hearing or eliminate background noise. Adjusting to a hearing aid is a gradual process that involves learning to listen in a variety of environments and becoming accustomed to hearing different sounds. Try to become familiar with hearing aids under nonstressful circumstances a few hours at a time. Programs are available to help users master new listening techniques and develop skills to manage hearing loss. Contact your audiologist for further information about programs that may suit your individual needs.

What questions should I ask before buying hearing aids?

Before you buy a hearing aid, ask your audiologist these important questions:

• Are there any medical or surgical considerations or corrections for my hearing loss?
• Which design is best for my hearing loss?
• What is the total cost of the hearing aid?
• Is there a trial period to test the hearing aids? What fees are nonrefundable if they are returned after the trial period?
• How long is the warranty? Can it be extended?
• Does the warranty cover future maintenance and repairs?
• Can the audiologist make adjustments and provide servicing and minor repairs? Will loaner aids be provided when repairs are needed?
• What instruction does the audiologist provide?
• Can assistive devices such as a telecoil be used with the hearing aids?

Digital Hearing Aids: Current "State-of-the-Art"

by Todd A. Ricketts

There has been explosion in the number of digital hearing aids on the market in the last five years. At last count, there are 22 manufacturers with digital hearing aids marketed under 40 different model names. Manufacturers are moving toward their third or fourth generation of digital products. The technology is here to stay--but are digital hearing aids really better?

Digital hearing aids first came to market in 1987 with two manufacturers introducing hearing aids with digital signal processing (DSP) before the end of the 1980s. While high-tech for their time, these hearing aids had little success and were soon abandoned due to their large size and high battery drain.

Nearly a decade later, two separate manufacturers once again introduced digital hearing aids. By this time, the technology had improved so that these hearing aids could be produced in a range of popular styles, from behind-the-ear (BTE) to completely-in-the-canal (CIC). Despite their higher cost, they were well received by clinicians and consumers. This early success, combined with the promise of highly advanced signal processing, ensured that digital hearing aid technology had come of age.

So how far have we come? What is the current "state-of-the art" technology in digital hearing aids? Are digital hearing aids really superior to their analog counterparts? To determine whether digital hearing aids are better for patients, it is important to focus on the superior processing and features of these instruments. Digital hearing aids can't be described as if they are a separate entity from analog hearing aids. "Digital" simply indicates that the analog waveform is converted into a string of numbers for processing; and unfortunately, there is nothing inherently magical about this process. A linear, output-clipping, digital hearing aid could easily be built that would provide sound quality and speech recognition inferior to many analog hearing aids. Therefore, digital isn't superior just because it's digital, but because DSP allows manufacturers to create hearing aids with enhanced processing and features.

The Digital Advantage

Fortunately, for both dispensing audiologists and patients, there are features and advanced signal processing schemes available in current digital hearing aids that do have significant advantages over those found in analog instruments. Potential digital advantages include those related to:

Gain Processing. One of the primary benefits associated with flexible gain-processing schemes is the potential for increased audibility of sounds of interest without discomfort resulting from high intensity sounds. While this is more generally a benefit of compression rather than digital processing per se, the greatly increased flexibility and control of compression processing provided by DSP--such as input signal-specific band dependence, greater numbers of channels, and kneepoints with lower compression thresholds--can lead to improved audibility with less clinician effort. Expansion, the opposite of compression, has also been introduced in digital hearing aids. This processing can lead to greater listener satisfaction by reducing the intensity of low-level environmental sounds and microphone noise that otherwise may have been annoying to the user.

Digital Feedback Reduction (DFR). The most advanced feedback reduction schemes monitor for feedback while the listener is wearing the hearing aid. Moderate feedback is then reduced or eliminated through the use of a cancellation system or notch filtering. DFR can substantially benefit users who experience occasional feedback, such as that associated with jaw movement and close proximity to objects.

Digital Noise Reduction (DNR). This processing is intended to reduce gain, either in the low frequencies or in specific bands, when steady-state signals (noise) are detected. Although research findings supporting the efficacy of DNR systems are mixed, they do indicate that the DNR can work to reduce annoyance and possibly improve speech recognition in the presence of non-fluctuating noise. DNR is sometimes advocated as complementary processing to directional microphones. While directional microphones can reduce the levels of background noise regardless of its temporal content, they are limited to reducing noise from behind or to the sides of the user.

Digital Speech Enhancement (DSE). These systems act to increase the relative intensity of some segments of speech. Current DSE processing identifies and enhances speech based either on temporal, or more recently, spectral content. DSE in hearing aids is still relatively new, and its effectiveness is largely unknown.

Directional Microphones and DSP. The ability of directional hearing aids to improve the effective signal-to-noise ratio provided to the listener is now well established. In some cases, however, combining DSP with directional microphones can act to further enhance this benefit. In some hearing aids, DSP is used to calibrate microphones, control the shape of the directional pattern, automatically switch between directional and omnidirectional modes, and through expansion, reduce additional circuit noise generated by directional microphones.

Digital Hearing Aids as Signal Generators. Since digital hearing aids have a DSP at their heart, they are able to generate--as well as to process--sound. Current digital hearing aids use this capability to perform loudness growth and threshold testing in order to obtain fitting information specific to an individual patient's ears in combination with a specific hearing aid. Sound levels also can be verified through the hearing aid once it is fit. This technology has the potential both to increase accuracy of hearing aid fittings and potentially streamline the fitting process by reducing the need for some external equipment.

Current digital hearing aids are certainly exciting, and the future possibilities are endless. Before long, digital hearing aids will replace their analog counterparts altogether. We must, however, present this technology to patients in an informative and educational manner. Like many other high-tech devices, high expectations often accompany digital hearing aids. Counseling patients about appropriate expectations will continue to be more--not less--important as technology continues to advance.

Todd A. Ricketts is an assistant professor in the department of hearing and speech sciences at Vanderbilt University and director of the Dan Maddox Hearing Aid Research Laboratory. His research interest is focused on various high-tech aspects of hearing aids and their impact on listener's benefit from, and satisfaction with, amplification. Contact him by email at todd.a.ricketts@vanderbilt.edu