Revised criteria for mild cognitive impairment: validation within a longitudinal population study

Abstract

Background: Mild cognitive impairment (MCI) refers to the transitional zone between normal ageing and dementia. Current criteria perform poorly within the general population setting. Revisions have been proposed based on results obtained from clinical and epidemiological studies.

Objective: To evaluate revised diagnostic criteria for mild cognitive impairment (MCI-R) incorporating changes in activity level and non-mnesic cognitive functioning.

Method: MCI-R subjects were recruited from a representative network of general practitioners in the south of France. A computerized neuropsychometric examination was given. At 2 years of follow-up, a diagnosis of dementia was made by a neurologist using DSM-IIIR criteria and without knowledge of the results of the cognitive testing. Rates of conversion to incident dementia were assessed by receiver operating characteristics analysis.

Results: The MCI-R prevalence was found to be 16.6% using revised criteria. A significantly better prediction of transition to dementia (AUC = 0.80, sensitivity: 95%, specificity: 66%) was obtained with MCI-R than with the previous MCI criteria (AUC = 0.48, sensitivity: 5%, specificity: 91%). The predictive power was found to increase when MCI subtypes were combined.

Conclusion: Incorporating the possibility of change in activity level and alteration of non-mnesic cognitive functions have been found to ameliorate the original algorithm and better define subjects converting to dementia. This definition may be applicable to both clinical and population research.