With digital technology, a computer chip converts the incoming sound into digital code, then analyzes and adjusts the sound based on your hearing loss, listening needs and the level of the sounds around you. The signals are then converted back into sound waves and delivered to your ears. The result is sound that's more finely tuned to your hearing loss. Digital hearing aids are available in all styles and price ranges.

Source: http://www.mayoclinic.org/diseases-conditions/hearing-loss/in-depth/hearing-aids/ART-20044116/