To understand the difference between analog and digital hearing aids, you need to first appreciate the history of analog versus digital, and the different ways that they process and amplify sounds. Analog hearing aids appeared first, and were the standard in most hearing aids for a long time. Then with the arrival of digital signal processing (DSP) technology, digital hearing aids also started to appear. The majority of (roughly 90%) hearing aids purchased in the United States at this point are digital, although you can still get analog hearing aids because some people have a preference for them, and they are often cheaper.
The way that analog hearing aids work is that they take sound waves from the microphone in the form of electricity and then amplify them, delivering louder versions of the sound waves to the speakers in your ears “as is.” Digital hearing aids take the sound waves from the microphone and convert them to digital binary code, the “bits and bytes” and “zeros and ones” that all digital devices understand. Once the sound has been digitized, the microchip inside the hearing aid can manipulate the data in sophisticated ways before converting it back to analog sound and passing it on to your ears.
It is important to remember that both analog and digital hearing aids have the same function – they take sounds and amplify them so you can hear them better. Both analog and digital hearing aids can be programmable, which means that they contain microchips which can be modified to adjust sound quality to suit the individual user, and to create different configurations for different listening environments. As an example, there might be distinct settings for low-noise locations like libraries, for busy restaurants, and for outdoor spaces such as sports stadiums.
But beyond programmability, the digital hearing aids generally offer more controls to the wearer, and offer additional features because of their ability to manipulate the sounds in digital form. For example, digital hearing aids may offer numerous channels and memories, allowing them to save more location-specific profiles. They can also employ advanced algorithms to identify and minimize background noise, to eliminate feedback and whistling, or to selectively detect the sound of voices and “follow” them using directional microphones.
As far as pricing is concerned, analog hearing aids are in most cases cheaper, although some digital hearing aids are approaching the price of analog devices by eliminating the more sophisticated features. There is commonly a perceivable difference in sound quality, but the question of whether analog or digital is “better” is up to the individual, and the ways that they are used to hearing sounds.