Feature Definitions

Digital

The two most common technologies used in hearing aids are analog and digital. Digital is newer and considered to be much more flexible, capable of doing more operations, and the only technology used in modern hearing aids.

Size

All open fit/open ear hearing aids are smaller than the Behind-The-Ear (BTE) hearing aids we have had in the past. Due to very small tubes going from the hearing aid into the ear canal these open fit hearing aids are among the least visible hearing aids on the market today.

Battery size does effect the size of open fit hearing aids, so smaller batteries allow for smaller hearing aids. Smaller batteries also mean shorter battery life.

• Small = Hearing aids that use size 10A batteries
• Medium = Hearing aids that use 312 batteries
• Large = Hearing aids that use size 13 batteries
• Full size = These hearing aids use size13 batteries and have larger components for higher power.

Channels/Bands

Human speech ranges in frequencies from 250 HZ to 6000 HZ ---roughly. Hearing aids are built so that this group of frequencies, 250 to 6000 HZ, is divided into smaller groups called bands or channels.

Each of these smaller bands/channels is controllable individually, as is the overall spectrum of frequencies.

By controlling, or setting each of the smaller bands/channels of frequencies to address the loss shown on your audiogram, the hearing aid is programed for your unique hearing loss.

Controlling the overall group of bands/channels, as one, varies the volume.

Both bands and channels also play an important role in how ‘surgically’ the noise is removed. When a noise is detected in one band/channel the amplification of that band/channel is reduced so the noise is not amplified.

Channels can have multiple bans within its segment of frequencies. Somewhere in the area of 12 channels/bands the point of diminishing returns is reached

Receiver In Canal

RIC (receiver-in-the-canal) hearing aids have the speaker located at the end of the tube that goes into the ear canal rather than in the body of the hearing aid and then “piped” into the ear canal. RIC hearing aids have slightly higher fidelity of sound and higher maintenance, too.

Memories

Memories allow multiple programs to be installed to cope with changing sound and noise environments.

Usually the first memory is the default program. Default programs are adaptive, meaning that the hearing aid will vary how it amplifies depending on how noisy the surrounding area is. Adaptive directionality is also available in more advanced hearing aids, meaning that the hearing aid will go into a directional mode when it detects noise and then back to omni-directional in quieter environments.

Most people find it handy to have a noise reduction program in the second memory so by pressing the memory button once the hearing aid goes into maximum noise reduction combined with a directional microphone mode.

For quiet areas, or when you want to hear all sounds such as when listening to music, the third memory has a program that contains a minimum of noise reduction and feedback reduction so sounds will come through with very little modification other than appropriate amplification. The microphones are locked into an omni-directional mode.

Additional memories are available on some hearing aids but many people feel three memories cover the sound-world pretty well and make it easy and quick to get to the program you want.

Volume Control

Volume control is generally considered to be a manual adjustment that the user can control. All hearing aids have automatic gain control that is designed to make soft sounds audible, loud sounds tolerable, and is done automatically with limits programmed into the hearing aid.

A volume control will enable the user to adjust the limits programmed into the hearing up or down about 10 decibels on a temporary basis.

Totally Automatic

For a hearing aid to be classified as Totally Automatic it will need to have multiple programs that it switches between, determined by surrounding noise. The switching technology needs to be very sophisticated to be able to match or even exceed performance of hearing aids that can be manually switched with a button.

For a hearing aid to be rated good, better, or best depends on how well the hearing aid’s technology determines the best program to use and how transparently it switches. The more natural the sound world is as the hearing aid switches programs the better the rating.

On Board Controls

Controls on hearing aids usually have one or more of:

• 1 A momentary button used to change from one memory to the next
• 2 A button used to increase the level of volume
• 3 A rocker switch where pushing on one end does one function while the other end does another function
• 4 A wheel that will control volume

Remote Control

Remote controls for hearing aids are small enough to comfortably fit in a pocket. A remote control will enable more functions than can be put on a hearing aid itself. This means a very small hearing aid with no room on the case for any control can have any or all of the latest features accessed by using the remote control.

Most remotes will work up to arm’s-length distance from the hearing aids.

Directional Microphones

Microphones are the electronic component that picks up sound. Microphones are very small and can be made to pick up more sound in one direction than all others. This is called a directional microphone.

Most modern microphones can operate in omi-directional or directional modes. Some microphones are smart enough to operate in an adaptive directional mode, by determining the amount and type of noise in the surrounding sound environment and switching into the mode, omni or directional, that best fits the sound environment you are in.

More sophisticated microphones and the circuitry that control them are being developed.

To rate higher in our good, better, best rating the directional microphone will need to be adaptive, meaning it can go from omni-directional to directional. It will also get a higher rating the more effectively it can track and eliminate moving sources of noise.

Noise Reduction

Technology to separate voices from other sounds is continuously being improved. Each manufacturer has a patented process and trade marked name for noise reduction.

What Noise Reduction can really do now is determine if a sound is a non-modulated sound, road noise in a car for example, or a modulated sound like a voice.

When road noise or other non-modulated sound is detected the Channel where the noise is occurring de-powers and reduces amplification of the noise. The more Channels a hearing aid has the more ‘surgically’ a noise can be removed.

It is pretty easy to tell improved Noise Reduction as you move up in the number of Channels a hearing aid has until you reach 12 Channels. From there on up it gets much harder to detect big improvements in performance, but fairly easy to detect big advancements in price.

Rating points are given for adaptive noise reduction and clarity of sound while noise reduction is being applied.

Feedback Management

Acoustic Feedback, is also known as squealing, buzzing, ‘your aids are talking to you’, etc. Acoustic Feedback is an unwanted sound a hearing aid makes when the hearing aid’s output is picked up by the microphone and re-amplified causing the amplifier to go into distortion.

The Feedback Reduction circuit is capable of canceling feedback by sending out a canceling sound or reducing amplification in the Channel where the feedback is occurring.

What Feedback Reduction can do now is greatly improved over what it was capable of even a few years ago. Feedback is the limiting factor to how much of a hearing aid’s total power can be used to correct a hearing loss.

Once feedback occurs, by overpowering the Feedback Reduction circuit’s ability to cancel it, the limit of amplification has been reached. At the point where increasing amplification results in feedback, amplification must be decreased to stop the squealing.

Rating points are given for how effectively the hearing aid’s technology detects feedback and cancels it. In addition clarity or lack of distortion while canceling feedback is also important.

Sudden Noise Protection

This feature helps make hearing aids acoustically comfortable by ramping up sudden loud noises, such as a dropped dish. This is newer technology and is improving. Points are given for effectiveness.

Wind Noise Reduction

Wind noise is an important feature for those that spend time in the outdoors by reducing the roar of wind across the microphone. This feature is improving but is not effective in gusty wind conditions.

Telecoil

Telecoils help with telephones that are rated hearing aid compatible. Telecoils are also used in some hearing impaired systems where a neck loop is worn.

Aid to Aid Communication

Communication from one hearing aid to the other is a very low strength signal designed to keep both hearing aids operating in the same mode at the same volume. Better, more natural hearing is achieved when hearing aids are in balance.

BlueTooth

Being able to couple your hearing aids with a BlueTooth-enabled device, such as a cell phone, allows phone conversations to be heard through your hearing aids. This is the best telephone system for hearing impaired people that have trouble hearing on the telephone.

This technology is developing and will improve.

DAI (Direct Audio Input)

DIA is only on Large and Full Size hearing aids due to the need for terminals on the outside of the case. Using DAI allows other devises to connect directly to the hearing aids and input their audio signal. Devise choices are increasing but are limited at present.

Batteries

Battery technology is improving and we are seeing rechargeable batteries being introduced. At this time rechargeable batteries need to be recharged nightly and replaced yearly. Cost for rechargeable batteries is, at best, about the same cost as using conventional zinc air batteries.

Conventional Hearing Aid Batteries cost less than a dollar per battery and are very easy to change.

Conventional Battery size, color code, and life span.

• Size 10 A Yellow 5 days to one week
• Size 312 Brown 9 days to two weeks
• Size 13 Orange 16 days to three weeks
• Size 675 Blue Three weeks plus

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