These instruments contain electronic circuitry but the adjustments are programmed using computer software. Eventually, these hybrids will be replaced with all-digital instruments. Research, however, has not yet identified which processing adjustments are optimal for various listening situations. Anecdotal reports, however, indicate subjective preference for the sound quality and comfort of digital instruments. The digital instrument can be adjusted far more precisely than the analog instrument, resulting in improved sound quality.
Adjustments are possible in some analog aids, but the possibilities are far less extensive.
The digital instrument eliminates circuit noise, which can be a problem for some clients, particularly those with normal or near normal low frequency hearing. Digital hearing aids will not restore hearing to normal, nor will they make listening in noise comparable to listening in quiet. Digital technology can produce cleaner and more natural sound, but will not produce CD sound quality. The major disadvantage of digital technology is cost. Because of the high cost, consumers must decide whether the price differential between analog and digital is worthwhile.