What is a Digital Hearing Aid. Lets first learn a little more about what "Digital" means.
Digital describes electronic technology that generates and processes data in terms of two states: a ONE or a ZERO -

Prior to digital technology or digital hearing aids, sending sound waves was limited to analog hearing aid technology,
This where the analog signal is modified in some way, such as amplifying the strength of the signal or the frequency of the signal, in order to add information to the signal.
AM Radio uses analog technology.

The biggest complaint with Analog hearing aids is that they amplified all sounds. Analog hearing aids basically take sounds and make them louder. Which means a lot of noise can get in the way of conversations.

An analog is signal represented as a series of sine waves. The term originated from the natural fluctuations of the human voice

Lets Look look at the comparison of a Digital Signal and Analog Signal.

This image below is diagram of the processing stages in a digital hearing aid - this is how the hearing aid "hears"

The acoustic sound waves (say people talking) of the input signal are captured by the hearing aid microphones, then passed on to the A/D converter
The A/D converter translates the analog signal into a digital signal,
Then it goes to the Digital Processor where engineers can apply advanced features.
Finally, the processed digital signal is translated back into an analog signal with the D/A convertor, which is transformed into acoustic sound waves into the user’s ear by the receiver.
The obvious advantages of a digital hearing aid is that there are unlimited ways in which the digital signal can be manipulated.
The number of features that can be applied like:

    • Directional Microphones

    • Channels

    • Bands

    • Noise Suppression,

    • Abrupt Noise Cancellation

These possibilities offer significantly greater applications AND BENEFITS than found in an analog hearing aid.

When you have the ability to manipulate the signal - digitally - and the sounds your want to hear - which means you can also block out the sounds you do not want to hear - the better the customer experience with hearing aids.