Abstract
Multi-disciplinary research has revealed evidence of significant abnormality in a much wider range and level of information processing than that currently definitive for amnestic mild cognitive impairment (MCI). This raises the possibility that the contemporary approach to MCI is inappropriately delimited, and the true nature and extent of brain dysfunction and thus disease burden, underestimated. It follows therefore that the closely related concept of subjective cognitive impairment (SCI) may be similarly constrained. Although research into the wider range of potential brain dysfunction in MCI and SCI is in its infancy, as yet precluding systematic reviews, we present here findings to prompt debate about SCI with respect to its clinical assessment and its personal and societal burden.