A hearing aid that processes sound in digital form. Digital techniques were used in hearing aids starting in the early 1990s when programmable devices were the first to amplify specific frequencies rather than all of them. In addition, loud noises can also be suppressed. By the mid-1990s, "100% digital" hearing aids were introduced that converted the analog sound to digital, processed it in digital form and converted it back to analog. Digital processing offers faster response times and more accurate sound filtering. The devices are programmed in the ear in real time by the hearing aid practitioner, who obtains immediate feedback from the user.