So you’ve decided to get a set of hearing aids… Good for you! Hearing aids are the best way to keep ourselves healthy, happy and wise once hearing loss comes into the picture.If you’ve looked around at hearing aids at all, you probably have a lot of questions. There are a lot of options on the market in a wide variety of shapes, sizes, colors, and feature sets. While there are many resources to help you navigate your options—not to mention the guidance of helpful hearing care professionals!—let’s talk today about digital technology, what it does for hearing aids, and how it can help you stay connected better than ever before.
All Hearing Aids Are Digital
Well, just about all. With very few exceptions, hearing aids today rely on digital technology because of how it allows us to change the sound. While this is an ever-more-complicated process, maybe we can help you get a little insight into it today, and see how these complicated changes make using your hearing aids a lot easier!
First, let’s note that hearing aids don’t simply make sound louder. They make sound louder – for you. At the very minimum, this requires an equalizer—or EQ—similar to the one on your stereo, but much more precise. The equalizer alters the level (volume) of different frequencies coming into the hearing aid based on the frequencies where you have hearing loss.Frequencies are measured in hertz (Hz), which indicates the cycles per second at which the sound vibrates. Low frequencies sound lower in pitch, and high frequencies sound higher. Humans can hear from about 20 Hz to about 20 kHz (20,000 Hz), though most of us lose the ability to hear as high as 20 kHz by our mid-20s.If you have 40 dBHL (decibels hearing level) of loss at 6 kHz, 30 dBHL at 3 kHz, and no loss at 500 Hz, then we want to amplify 40 dB at 6 kHz, 30 dB at 3 kHz, and not at all at 500 Hz. This not only sounds better—as it provides a sound to your brain that looks more like what it is used to hearing—but is also better for your hearing. By not over-amplifying frequencies where you don’t need amplification, we can prevent further hearing damage due to loud noise.Equalizers exist in the analog domain, where sound is manipulated with electrical devices that are not computers. For decades, this was how hearing aids worked. Sound came into a microphone, was equalized for your hearing loss profile using an analog equalizer, then was amplified and sent out to your eardrum.
The Digital Revolution
As we entered the 21st century, digital technology became more common. Digital equalizers can mimic the way analog equalizers work, or do the job in a different way that can improve the sound. How does this work?Analog signal processing is constrained by time and the world of physics. While this is fine for many and maybe most things, what if you want to reduce the level of not just frequencies but of a specific sound? In other words, what if you want to change not just the level of 3 kHz, but of a sound that moves around between 1 kHz and 4 kHz?Now you need to identify that sound, and change the equalizer from moment to moment to reduce the level of sound at the constantly changing frequency! Not only that, but what if there are multiple sounds in the environment that are all moving at the same time? Now you have hundreds of frequencies that need to be altered from moment to moment as the sound changes! Even if you had a team of a hundred hearing care professionals tweaking the equalizer on your hearing aids at the same time, they could never do it!
Never-Before Imagined Sound Processing
With trainable computers available today, we can use digital equalizers and other digital signal processors (DSP) to effectively split the sound coming into a set of hearing aids into “speech” and “everything else.” Once that has been done, we can also change the dynamics of each independently, so that speech never gets too quiet for you to hear or so loud that it is painful. The level of background noise can even be adjusted independently of the level of speech!In some situations, you might wish to hear more of what’s going on around you, while at other times you may only want to amplify speech. With today’s digital hearing aids, you can do that with the simple adjustment of a setting from your smartphone.Some of today’s digital hearing aids will even automatically recognize when the environment is changing and adjust their programming accordingly. They can even communicate with each other to improve the spatial location of sounds in the environment, which helps you feel more comfortable and balanced while walking. That will allow you to amble effortlessly while you concentrate on a conversation with your walking buddy.It’s really amazing how far hearing aids have come since the year 2000, and even in the last decade! If you or a loved one may be in need of hearing aids, make an appointment for a hearing test and find out how today’s hearing aids can help you hear better than ever!