INTRODUCTION AND OBJECTIVES: During the last 15 years several diagnostic categories have appeared to describe a group of adults with cognitive impairment compared to their age-matched standardized norms but without dementia. In this work, the main studies relating to these categories are reviewed and compared in order to establish if they define similar or different aged populations. DEVELOPMENT: Differences in prevalence or in prognostic values among studies are probably due to the selection of diagnostic categories or the differences in the application of inclusion/exclusion criteria. Genetic and neuroimaging data have contributed to reinforce the validity of the proposed classifications to identify the age related cognitive decline. CONCLUSIONS: The criteria used seems to be very important in the inclusion of subjects closer to normal aging or to dementia. In this respect further longitudinal studies and a consensus from previous described categories are need to reliably identify aged population with lower cognitive function compared to their age norms but different from patients in the initial stages of dementia.
INTRODUCTION AND OBJECTIVES: During the last 15 years several diagnostic categories have appeared to describe a group of adults with cognitive impairment compared to their age-matched standardized norms but without dementia. In this work, the main studies relating to these categories are reviewed and compared in order to establish if they define similar or different aged populations. DEVELOPMENT: Differences in prevalence or in prognostic values among studies are probably due to the selection of diagnostic categories or the differences in the application of inclusion/exclusion criteria. Genetic and neuroimaging data have contributed to reinforce the validity of the proposed classifications to identify the age related cognitive decline. CONCLUSIONS: The criteria used seems to be very important in the inclusion of subjects closer to normal aging or to dementia. In this respect further longitudinal studies and a consensus from previous described categories are need to reliably identify aged population with lower cognitive function compared to their age norms but different from patients in the initial stages of dementia.