When trying to fully understand the difference between analog and digital hearing aids, you need to first appreciate the history of analog vs digital, and the different ways that they process and amplify sounds. Analog hearing aids came out first, and were the standard in most hearing aids for many years. Subsequently, with the introduction of digital signal processing (DSP) technology, digital hearing aids also started to appear. Most (roughly 90%) hearing aids sold in the United States at this point are digital, although you can still find analog hearing aids because some people have a preference for them, and they are often cheaper.
The way that analog hearing aids operate 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. Once the sound is digitized, the micro-chip inside the hearing aid can process and manipulate the information in complex ways before converting it back to analog sound and delivering it to the ears.
Analog and digital hearing aids perform the same function – they take sounds and boost them to allow you to hear better. Both analog and digital hearing aids can be programmable, which means that they contain microchips which can be modified to alter sound quality to match the individual user, and to develop various settings for different environments. The programmable hearing aids can, for example, have one particular setting for listening in quiet spaces, another for listening in noisy restaurants, and still another setting for use in large stadiums.
Digital hearing aids, due to their ability to manipulate the sounds in digital form, generally have more features and flexibility, and are commonly user-configurable. For example, digital hearing aids may offer multiple channels and memories, permitting them to save more location-specific profiles. Other capabilities of digital hearing aids include the ability to automatically reduce background noise and eliminate feedback or whistling, or the ability to prefer the sound of voices over other sounds.
Price-wise, most analog hearing aids continue to be less expensive than digital hearing aids, however, some reduced-feature digital hearing aids fall into the same general price range. Some users notice a difference in the sound quality produced by analog versus digital hearing aids, but that is largely a matter of personal preference, not really a matter of whether analog or digital is “better.”