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Because of the development of digital sound, many new devices have emerged or have been improved - most notably in music. Now that it's possible to convert analog sound waves into digital code, musical recordings can deliver the highest quality, distortion free sound, making compact discs (CDs) one of the most successful inventions of the 20th century. We can now enjoy new re-mixed musical recordings freed of distortion and carry it with us on our phones, iPods, and tablets.
Sound quality is so crisp in some telecommunication features such as voicemail (depending on the provider), we're often fooled into thinking we've reached someone live! And Dolby stereo really enlivens motion pictures now. We also can experience excellent sound quality on our personal computers with sophisticated, high-functioning sound cards, on videocassette recorders (VCR's), stereo televisions, and the newest-digital video discs (DVDs). So how does that benefit assistive technology? With the most sophisticated hearing aids ever made for people with deafness or hearing impairments, higher-functioning augmentative communication devices—to give a non-verbal person a voice, and talking books and screen-readers for people with blindness. The development of sound technology has changed everything!
Digital Hearing Aids
Digital refers to Digital Audio Processing (DAP). A hearing instrument that is truly digital converts an analog sound wave into digital code, a series of 0s and 1s. Specific sections of coded or digitized sound can then be isolated and processed or amplified based upon the specific hearing loss and listening preferences of the user. In addition, a truly digital hearing instrument does not add noise to the signal as it passes through the electronic circuit. A DAP hearing instrument is virtually distortion free. "Digital" is often confused with a "computer" hearing instrument. The latter always refers to the way the controls of the hearing instrument are set using a computer or programming box. This has nothing to do with the way the sound signal is processed which distinguishes a true digital hearing instrument.
Digital hearing aids aren't superior because they're digital, but because of the enhanced features available. See this article from the American Speech-Language-Hearing Association for an explanation of the features. 
Two companies carrying digital hearing instruments (there are many) include:
Note: Infinitec does not endorse or recommend the above-mentioned products and has no liability for the results of their use. Infinitec has received no consideration of any type for featuring this product on this Web site. The information offered herein is a summary; it is not comprehensive and should be carefully evaluated by consumers with the assistance of qualified professionals. The intention of Infinitec is to offer consumers a brief overview of various assistive technology devices and their applications.