Mild cognitive impairment--a review of prevalence, incidence and outcome according to current approaches.

OBJECTIVE Mild cognitive impairment is associated with an increased risk of developing dementia. However, agreement needs to be reached on clearly specified diagnostic criteria for mild cognitive impairment. The present paper critically reviews the different constructs of mild cognitive impairment on the basis of the available empirical evidence. METHOD All published papers on mild cognitive impairment during the last 15 years on Medline and other databases were reviewed. RESULTS Age-specific prevalence and incidence rates according to the different constructs as well as the prognostic significance of the different constructs concerning the development of dementia are reported. Furthermore, a brief summary of recent research on possible risk factors for a negative course of mild cognitive impairment is provided. CONCLUSION As there is no construct to date that pools all efforts of defining mild cognitive impairment, the review provides suggestions for an agreement on constructive terminology and research practice.