When trying to fully understand the difference between analog and digital hearing aids, it is important to first appreciate the history of analog versus digital, and the different ways that they amplify and process sounds. Analog technology appeared first, and consequently most hearing aids were analog until digital signal processing (DSP) was invented, after which digital hearing aids appeared. The majority of (roughly 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 typically less expensive.
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, sending 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 transform them to digital binary code. This digital data can then be altered in many complex ways by the micro-chip within the hearing aid, before being converted back into ordinary analog signals and sent to the speakers.
Both analog and digital hearing aids perform the same work – they take sounds and amplify them to enable you to hear better. Both types of hearing aids can be programmed by the dispensers of the hearing aids to produce the sound quality desired by the user, and to create configurations ideal for different listening environments. The programmable hearing aids can, for instance, have one setting for use in quiet rooms, another setting for listening in loud restaurants, and still another for listening in large auditoriums.
Digital hearing aids, due to their capacity to manipulate the sounds in digital form, often offer more features and flexibility, and are often user-configurable. For example, digital hearing aids may offer multiple channels and memories, permitting them to store more environment-specific profiles. Other capabilities of digital hearing aids include the ability to automatically minimize background noise and eliminate feedback or whistling, or the ability to prefer the sound of human voices over other sounds.
Cost-wise, most analog hearing aids continue to be less expensive than digital hearing aids, however, some reduced-feature digital hearing aids fall into a similar general price range. Hearing aid wearers do detect a difference in the sound quality generated 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.”