Hearing Aid Technology
Hearing aid have been around for a long time and things have changed over the years. Over the last several years advances in digital technology have been integrated into the hearing aids. This has allowed for smaller and more effective hearing aids. There are still size and performance limitations, but the improvements of the last few years have been dramatic.
Below is a list of the improvements digital processing brings to the hearing aid world. Not all digital hearing aids offer all of these enhancements.
When I began my career as an audiologist, the prescription (or matrix) of the hearing aid was ordered and built at a lab in another state. Once it was built it could be fine tuned in the office, but not substantially altered. Digital technology makes the hearing aid very flexible. It allows me to reprogram the hearing aid if there is a change in your hearing. It also allows me to set the hearing aid for your hearing loss in my office, while you are wearing it. This imporved precision means better hearing for you.
Under certain conditions, all hearing aids will make a whistle or feedback. In the old days this was controlled by reducing the volume. The squeal would stop, but now the wearer wasn’t hearing as well. Today many digital hearing aids now use a feedback cancellation system that virtually eliminates feedback. This allows for more consistently high performance and less annoyance.
Strategies for hearing better in noise
The first method of noise reduction is the use of directional microphones. These were available prior to the advent of the digital technology, but digital technology allows us to do more with directional technology. Some hearing aids are able to automatically identify and prioritize sounds coming from the front. This does not eliminate noise from behind, but it does minimize it and emphasize what you are focusing on.
Digital Noise Reduction
The computer in the hearing aid analyzes the kind of sound coming into the hearing aids. The hearing aid looks at frequency, modulation and amplitude of the incoming signal to determine if the sound is speech or noise. When noise is suspected in given frequency range the volume for that frequency band can be reduced.
This is the opposite of the concept discussed under Digital Noise Reduction. The computer in the hearing aid increases volume for a given frequency band when speech is present.
The role of the audiologist in fitting hearing aids has become more critical as the devices have become more sophisticated. Computer driven hearing aids will do what they are programmed to do. it is important that the person programming your hearing aids has a good knowledge of your hearing and environments so that you can hear as well as possible.