Aural rehabilitation is a life long process in spite of advanced innovative implant technology. Existing standard therapy is inadequate for some people, because even after years of surgery many implant users does not obtain significant benefits, like improved understanding of spoken sentences. In many cases it seems that the speech comprehension deficits are linked to particular cognitive functions in cochlear implant users, including memory and attention. In this study we will test whether a computer-based set of "cognitive fitness" or "brain training" games designed to improve memory and attention will help cochlear implant and hearing aid users to understand speech better.