The course of cognitive impairment in preclinical Alzheimer disease: three- and 6-year follow-up of a population-based sample.
OBJECTIVE
To examine the ability of the total score and individual items from the Mini-Mental State Examination in predicting the development of Alzheimer disease (AD) across a 3- and 6-year period in a population-based sample, and to describe the longitudinal changes in these measures across the same follow-up periods.


METHODS
Prospective follow-up of a community-based cohort, with 3 times of testing across a 6-year period. At each time of measurement, participants were clinically examined by physicians to identify demented and nondemented participants according to Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition, criteria.


METHODS
The study population consisted of all participants who were nondemented at the first follow-up and participated in the second follow-up examination. Among those, 459 remained nondemented and 73 developed AD during the second follow-up period.


RESULTS
Baseline differences in the total Mini-Mental State Examination score and the delayed memory item were seen 6 years before eventual dementia diagnosis (P<.01). Analysis of the longitudinal changes showed no differences in the rate of decline for the incident AD or nondemented group between time 1 and time 2 (P>.10). However, the incident AD group exhibited precipitous declines in 8 of the 10 subscales between time 2 and time 3, the point at which they were clinically diagnosed (P<.01). Logistic regression analyses showed that only the delayed memory item was a significant predictor of who would develop AD, independent of age, sex, and years of education, at both of the first 2 times of measurement (P<.001).


CONCLUSIONS
The diagnosis of AD is preceded by a long preclinical phase in which deficits in memory performance are most common. These deficits remain relatively stable up until the time that a dementia diagnosis can be rendered. Arch Neurol. 2000.
Small
B J
BJ
Department of Gerontology, Mailbox SOC 107, University of South Florida, 4202 E Fowler Ave, Tampa, FL 33620, USA. bsmall@luna.cas
Fratiglioni
L
L
Viitanen
M
M
Winblad
B
B
Bäckman
L
L
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000523:psychology*; D000704:Analysis of Variance; D003072:Cognition Disorders / Q000523:psychology*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009483:Neuropsychological Tests; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales