A bit of history and an explanation of how analog devices work vs how digital devices work is necessary to understand the differences between digital and analog hearing aids. Historically, analog technology emerged first, and as a result most hearing aids were analog until digital signal processing (DSP) was developed, after which digital hearing aids appeared. The majority of (up to 90%) hearing aids sold in the US at this point are digital, although you can still get analog hearing aids because some people prefer them, and they’re often less expensive.
Analog hearing aids handle incoming sounds by taking the electrical sound waves as they emerge from a microphone and amplifying them “as is” before sending them to the speakers in your ears. Digital hearing aids take the sound waves from the microphone and transform them to digital binary code, the “bits and bytes” and “zeros and ones” that all digital devices understand. After the sound is digitized, the microchip inside the hearing aid can manipulate the data in sophisticated ways before transforming it back to analog sound and passing it on to the ears.
It is important to remember that both analog and digital hearing aids serve the same purpose – they take sounds and boost 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 customized to adjust sound quality to match the user, and to develop various settings for different environments. For example, there can be different settings for low-noise locations like libraries, for noisy restaurants, and for outdoor spaces such as sports stadiums.
But beyond programmability, the digital hearing aids often offer more controls to the user, and offer additional features because of their ability to manipulate the sounds in digital form. They have an array of memories in which to store more environment-specific configurations than analog hearing aids. They can also employ advanced rules to identify and reduce background noise, to remove feedback and whistling, or to selectively detect the sound of human voices and “follow” them using directional microphones.
As far as pricing is concerned, analog hearing aids are in most cases less expensive, although some digital hearing aids are approaching the cost of analog devices by eliminating the more advanced 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.