Annual rate and predictors of conversion to dementia in subjects presenting mild cognitive impairment criteria defined according to a population-based study.
Elderly subjects diagnosed with mild cognitive impairment (MCI) are becoming the target of intervention trials. The criteria used for MCI are principally issued from prospective clinical studies, although longitudinal population-based studies having identified several cognitive predictors of dementia can be of great contribution in the definition of these criteria. This study was conducted to explore the external validity of MCI criteria issued from a longitudinal population-based study, and subsequently to identify the best predictors of the short-term conversion to Alzheimer's disease 2 years after the MCI diagnosis. Ninety elderly volunteers with memory complaint diagnosed with MCI on the basis of their functional and neuropsychological performances were followed up within 2 years. The potential predictors of the conversion to dementia collected at baseline included age, gender, educational level, size of temporal lobe, apolipoprotein E genotype and a series of neuropsychological measures (Mac Nair Scale, Mini-Mental State Examination, Benton Visual Retention Test, Isaacs Set Test, Digit Symbol Substitution Task, Letter Cancellation Task, digit span tasks and finger-tapping test). Within the 2 years, 29 subjects (32.2%) presented a conversion to dementia. The risk of conversion to dementia was associated with age and size of temporal lobe but not with gender, education, or apolipoprotein E4 genotype. Several neuropsychological measures were associated with the risk of conversion to dementia, but in a logistic regression performed with the significant variables found in the univariate analysis, only the Letter Cancellation Test was shown to be an independent predictor. In conclusion, the quite elevated conversion rates obtained show the usefulness, when defining MCI criteria, of considering not only memory impairment but also impairment in other cognitive areas, as well as mild impairment on higher-order activities of daily living. Among the variables considered, the Letter Cancellation Test proved to be a major predictor of short-term conversion to dementia.
Amieva
Hélène
H
INSERM Unit 593, Université Victor Ségalen, Bordeaux, France. Helene.Amieva@isped.u-bordeaux2.fr
Letenneur
Luc
L
Dartigues
Jean-François
JF
Rouch-Leroyer
Isabelle
I
Sourgen
Christophe
C
D'Alchée-Birée
Françoise
F
Dib
Michel
M
Barberger-Gateau
Pascale
P
Orgogozo
Jean-Marc
JM
Fabrigoule
Colette
C
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D053327:Apolipoprotein E4; D001057:Apolipoproteins E / Q000235:genetics; D015415:Biomarkers; D003072:Cognition Disorders / Q000453:epidemiology* / Q000473:pathology / Q000523:psychology*; D003704:Dementia / Q000453:epidemiology* / Q000473:pathology / Q000523:psychology*; D018450:Disease Progression; D004311:Double-Blind Method; D004493:Education; D005260:Female; D005500:Follow-Up Studies; D005544:Forecasting; D005838:Genotype; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011153:Population; D011237:Predictive Value of Tests; D012307:Risk Factors; D013702:Temporal Lobe / Q000473:pathology
D053327:Apolipoprotein E4; D001057:Apolipoproteins E; D015415:Biomarkers