Mild cognitive impairment: prevalence and predictive validity according to current approaches.

OBJECTIVES

Mild cognitive impairment is associated with an increased risk of developing dementia. However, there is no consensus on diagnostic criteria and different concepts have rarely been evaluated in population-based samples. This paper compares the prevalences and predictive validities for different concepts in a population-based study. The aim was to identify a concept with the best relation of sensitivity and specificity in the prediction of dementia.

MATERIAL AND METHODS

A community sample of 1045 dementia-free individuals aged 75 years and over was examined by neuropsychological testing in a three-wave longitudinal study.

RESULTS

Prevalence rates ranged from 3 to 36% according to the concept applied. Conversion rates to dementia over 2.6 years ranged from 23 to 47%. In addition, receiver operating characteristic curves indicated that all but one concept for mild cognitive impairment could predict dementia.

CONCLUSION

Mild cognitive impairment is very frequent in older people. Prevalences and predictive validities are highly dependent on the diagnostic criteria applied.