When trying to understand the difference between analog and digital hearing aids, it is important to first appreciate the history of analog vs digital, and the different ways that they amplify and process sounds. Historically, analog technology emerged first, and as a result most hearing aids were analog until digital signal processing (DSP) was invented, after which digital hearing aids appeared. Most (up to 90%) hearing aids sold in the United States at this point are digital, although you can still get analog hearing aids because some people prefer them, and they are often cheaper.
Analog hearing aids handle inbound sounds by taking the electrical sound waves as they leave a microphone and amplifying them “as is” before sending them to the speakers in your ears. On the other hand, digital hearing aids take the same sound waves from the microphone, however before amplifying them they turn the sound waves into the binary code of ones and zeros that all digital devices understand. After the sound has been digitized, the micro-chip inside the hearing aid can manipulate the data in complex ways before transforming it back into analog sound and delivering it to the ears.
Remember that analog and digital hearing aids have the same function – they take sounds and boost them so that you can hear them more easily. Both analog and digital hearing aids can be programmable, which means that they contain microchips that can be customized to alter sound quality to match the user, and to develop various configurations for different listening environments. As an example, there can be distinct settings for low-noise rooms like libraries, for busy restaurants, and for large areas such as sports stadiums.
Digital hearing aids, because of their ability to manipulate the sounds in digital form, often offer more features and flexibility, and are often user-configurable. They have an array of memories in which to store more location-specific configurations than analog hearing aids. They can also employ sophisticated algorithms to identify and reduce background noise, to eliminate 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 cheaper, although some digital hearing aids are approaching the price of analog devices by removing the more sophisticated features. Some users detect a difference in the sound quality generated by analog vs digital hearing aids, although that is largely a matter of personal preference, not really a matter of whether analog or digital is “better.”