Digital Hearing Instruments
Virtually all modern hearing instruments are digital, which simply means that incoming sounds are converted into numbers for processing by the instruments’ computer chip(s). Digital sound processing varies in sophistication among models of hearing instruments. As such, not all digital hearing instruments are equal in performance. Your audiologist will guide you through the myriad of hearing instrument technologies so that you get the right solution for your listening needs, expectations and budget.
This technology was developed to help people hear better when in noisy environments. The main problem with hearing in “background noise” is our definition of the word “noise”. We define “background noise” as simply any sound we don’t want to hear; however, hearing instruments don’t know what you want to hear or don’t want to hear. A directional microphone array improves the audibility of sounds coming towards you and lowers sounds coming from beside or behind you. In this way you’re able to tell your hearing instruments what you want to hear simply by facing it. Further, when you can position youself with your back to the “noise” you will perform even better. Most hearing instruments automatically adjust their microphone settings based on the sounds in your listening environment. This technology is a great improvement over past hearing aids, but nothing can entirely eliminate “background noise”.
Dynamic Feedback Cancellation
If you had a family member that wore older hearing instruments, you most likely remember a steady whistle being emitted from their ears. Historically, the only way to reduce acoustic feedback whistle was to lower the amplification or plug up the ear canal. Dynamic feedback cancellation, specifically Phase Cancellation, enables us to provide more high-pitch audibility without sacrificing amplification or plugging up your ear canal. (Note: if you wear modern hearing instruments and are still experiencing chronic acoustic feedback, contact your audiologist because you could have a buildup of cerumen (ear wax), a fit problem or the hearing instrument may not be inserted correctly).
This technology is comprised of two hearing instruments that continually communicate with one another wirelessly. Binaural processing can be used to improve the hearing insruments’ automated decision making capabilities, adjust the amplifiction characteristics of each instrument to maximize the overall signal-to-noise ratio and even to enhance the directoinality of a directional microphone array. People with demanding listening lifestyles should strongly consider this technology.
Many hearing instruments now have the ability to receive sound wirelessly from common electronic devices such as telephones, cell phones, televisions, game consols, music players, personal microphones and computers using Bluetooth technology. Some instruments have the wireless receiver right inside them and others use a neck-worn device called a Streamer. The benefit to you is a significantly improved signal-to-noise ratio, the ability to hear the wireless signal in boths ears (when wearing two hearing instruments), and improved sound quality because sounds are processed by your own hearing instruments. Hearing instruments with wireless connectivity are also compatibile with remote controls for those who desire manual control.
While not new, this technology is now considerably better and smaller than it has ever been. These systems are designed for patients with single-sided deafness, or for those with un-usable hearing in one ear. A transmitter worn on the poor ear sends the sounds from that side to a receiver worn on the good ear. This allows the wearer to hear sounds from all around them (in their better-hearing ear), even if those sounds are directed towards their bad ear.
Is there a volume control?
Not always. A digital instrument is constantly sampling the environment and “looking” for changes. If the user enters a noisy room, the incoming signals are quite loud and the instrument may turn itself down a bit. If the user is in a quiet setting, the instrument may turn itself up. A volume control can be added to a digital hearing aid if someone wishes to have this control. The goal of today’s hearing aids are to help the user hear speech in different listening situations. Some hearing aids have other automatic features to help in noise. We realize that many people are on the go and busy. It’s important to have a hearing aid that can meet these demands.
I’ve heard about “Open Fit” hearing aids. What are these?
The philosophy behind the open fit is to keep the ear canal as “open” as possible. In the past, at least part of the hearing aid was housed in the bowl of the ear and the ear canal. This enabled the amplified sound to stay in the ear and be delivered to the auditory system. This is a good idea, but not without drawbacks. One is the “occlusion affect”; your own voice may sound louder or hollow, simply because something is plugging up your ear (try putting your fingers in your ears and talking).
The portion that is inside the ear is a small soft silicone dome, or a molded, highly vented acrylic tip. There is a very thin tube that runs from this to the hearing aid. (See “styles” below for a picture).
Open fits have been widely accepted and extremely successful for a number of reasons. Some of these are:
- Less hollowness of own voice or “occlusion affect”
- More gain without feedback
- More natural sound
- Barely noticeable design
- Greater physical comfort in some cases
Open fit instruments are most beneficial for those with a high frequency hearing loss and are available by all major hearing aid companies.
HOW DO I KNOW WHICH HEARING INSTRUMENTS ARE RIGHT FOR ME?
Analog, digital, open fit hearing aids…it can be hard to keep everything straight! The audiologists at Hart Hearing Centers are particularly skilled at determining which aids and options make the best fit for an individual’s hearing loss and lifestyle.
Assistive Listening Devices (ALD’s)
What is an Assistive Listening Device?
An assistive listening device (ALD) is any type of device that can help someone function better in day-to-day communication situations. An ALD can be used with or without hearing aids to overcome the negative effects of distance, background noise, or poor room acoustics.
What are examples of ALDs?
FM systems, infrared systems, induction loop systems, one to one communicators, and amplified telephones are examples of ALD technology. All technologies are considered good and each has advantages and disadvantages.
FM systems use radio broadcast technology and operate on special frequencies assigned by the Federal Communications Commission. The personal FM system consists of a transmitter microphone used by the speaker and a receiver used by the listener. The receiver transmits the sound to headphones worn by the listener or to hearing aids either through direct audio input or through a looped cord worn around the neck. Personal FM systems are useful in a variety of situations such as in a classroom lecture, listening to a travel guide or book review, in a restaurant, in meetings, or in nursing homes or senior centers.
Infrared systems are often used in the home for TV listening, and, like the FM system, they are frequently installed in places of entertainment. Sound is transmitted using infrared light waves. For TV listening, the volume is set to a comfortable level for family members and the infrared system transmits the TV signal to the listener’s receiver, which can be adjusted to a desired volume.
Induction Loop Systems utilize an electromagnetic field to deliver sound. They are most common in large group areas but can also be purchased for individual use. An induction loop wire is permanently installed in a large room such as a church and connects to a microphone used by the speaker. The person speaking into the microphone creates a current in the wire which makes an electromagnetic field in the room. When the hearing impaired listener switches their hearing aid to the telephone setting, the hearing aid telecoil picks up the electromagnetic signal, and the volume can be adjusted through the hearing aids.
One-to-one communicators are personal amplifiers that are used to increase volume in face-to-face and small group conversations. They are boxes about the size of a deck of cards with both a microphone and listening cord connected to them. Both talker and listener share the same device.
Amplified telephones have built-in amplifiers and are hearing aid compatible, meaning they can be used with or without hearing aids. There are many different styles available including cordless and desk phones. Amplified telephones can be used with or without hearing aids and many have loud ringers and large key pads for dialing ease.
Contact an audiologist at Hart Hearing Centers for additional information on ALDs