Neuropsychological tests accurately predict incident Alzheimer disease after 5 and 10 years.
OBJECTIVE
To determine whether neuropsychological tests accurately predict incident Alzheimer disease (AD) after 5 and 10 years in participants of the Canadian Study of Health and Aging (CSHA) who were initially nondemented.


METHODS
The CSHA was conducted in three waves: CSHA-1 (1991 to 1992), CSHA-2 (1996 to 1997), and CSHA-3 (2001 to 2002). The 10-year prediction study included those who completed neuropsychological testing at CSHA-1 and received a diagnostic assessment at CSHA-3 (n = 263). The 5-year prediction study included those who completed neuropsychological testing at CSHA-2 and received a diagnostic assessment at CSHA-3 (n = 551). The diagnostic workup for dementia at CSHA-3 was formulated without knowledge of neuropsychological test performance at CSHA-1 or CSHA-2. The authors excluded cases with a baseline diagnosis of dementia or a prior history of any condition likely to affect the brain. Age and education were included in all analyses as covariates.


RESULTS
In the 10-year follow-up study, only one test (short delayed verbal recall) emerged from the forward regression analyses. The model with this test and two covariates was significant, chi2 (3) = 31.61, p < 0.0001 (sensitivity = 73%, specificity = 70%). In the 5-year follow-up study, three tests (short delayed verbal recall, animal fluency, and information) emerged from the forward logistic regression analyses. The model was significant, chi2 (5) = 91.34, p < 0.0001 (sensitivity = 74%, specificity = 83%). Both models were supported with bootstrapping estimates.


CONCLUSIONS
In a large epidemiologic sample of nondemented participants, neuropsychological tests accurately predicted conversion to Alzheimer disease after 5 and 10 years.
Tierney
Mary C
MC
Geriatric Research Unit, Sunnybrook and Women's College Health Sciences Centre, Toronto, Ontario, Canada. mary.tierney@sw.ca
Yao
Christie
C
Kiss
Alex
A
McDowell
Ian
I
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology*; D002170:Canada / Q000453:epidemiology; D015331:Cohort Studies; D003704:Dementia / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D004522:Educational Status; D005260:Female; D020022:Genetic Predisposition to Disease; D005820:Genetic Testing; D005838:Genotype; D006306:Health Surveys; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D009483:Neuropsychological Tests / Q000592:standards* / Q000706:statistics & numerical data; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012307:Risk Factors; D012737:Sex Factors