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1.  Cerebrospinal Fluid Biomarkers, Education, Brain Volume and Future Cognition 
Archives of neurology  2011;68(9):1145-1151.
Objective
To evaluate the combination of cerebrospinal fluid biomarkers of Aβ42, tau, and phosphorylated tau (ptau181) with education and normalized whole brain volume (nWBV) to predict incident cognitive impairment and test the cognitive/brain reserve hypothesis.
Design
Longitudinal cohort study.
Setting
Charles F. and Joanne Knight Alzheimer’s Disease Research Center of Washington University, St. Louis, Missouri.
Participants
Convenience sample of 197 participants aged 50 years and above, with normal cognition (Clinical Dementia Rating [CDR] of 0) at baseline, followed for a mean of 3.3 years.
Main outcome measure
Time to cognitive impairment (CDR ≥ 0.5).
Results
Three-factor interactions between the baseline biomarker values, education, and nWBV were found for Cox proportional hazards models testing tau (p=.03) and ptau (p=.008). Among those with lower tau values, nWBV (hazard ratio [HR]=.54, 95% confidence interval [CI]=.31–.91; p=.02), but not education, was related to time to cognitive impairment. For participants with higher tau values, education interacted with nWBV to predict incident impairment (p=.01). For individuals with lower ptau values, there was no effect of education or nWBV. Education interacted with nWBV to predict incident cognitive impairment among those with higher ptau values (p=.02). In models testing Aβ42, larger nWBV was associated with a slower time to cognitive impairment (HR=.84, 95%CI=.71–.99, p=.0348), but there was no effect of Aβ42 or education.
Conclusions
Among individuals with higher levels of CSF tau and ptau, but normal cognition at baseline, time to incident cognitive impairment is moderated by education and brain volume as predicted by the cognitive/brain reserve hypothesis.
doi:10.1001/archneurol.2011.192
PMCID: PMC3203689  PMID: 21911695
2.  Role of family history for Alzheimer biomarker abnormalities in the adult children study 
Archives of Neurology  2011;68(10):1313-1319.
Objective
To assess whether family history (FH) of Alzheimer’s disease (AD) alone influences AD biomarker abnormalities.
Design
Adult Children Study (ACS).
Setting
Washington University's Knight Alzheimer's Disease Research Center.
Participants
Cognitively normal middle to older age individuals with and without a FH for AD (n=269).
Main Outcome Measures
Clinical and cognitive measures, magnetic resonance imaging (MRI)-based brain volumes, diffusion tensor imaging (DTI)-based white matter microstructure, cerebrospinal fluid (CSF) biomarkers, and molecular imaging of cerebral fibrillar amyloid with positron emission tomography (PET) using the [11C] benzothiazole tracer, Pittsburgh Compound-B (PIB).
Results
A positive FH for AD was associated with an age-related decrease of CSF Aβ42; the ε4 allele of apolipoprotein E (APOE4) did not alter this effect. Age-adjusted CSF Aβ42 was decreased for individuals with APOE4 compared with those without, and the decrease was larger for individuals with a positive FH compared with those without. The variation of CSF tau and PIB mean cortical binding potential (MCBP) increased by age. For individuals younger than 55, an age-related increase in MCBP was associated with APOE4, but not FH. For individuals older than 55, a positive FH and a positive APOE4 implied the fastest age-related increase in MCBP. A positive FH was associated with decreased fractional anisotropy from DTI in the genu and splenium of the corpus callosum.
Conclusion
Independent of APOE4, FH is associated with age-related change of several CSF, PIB and DTI biomarkers in cognitively normal middle to older age individuals, suggesting that non-APOE susceptibility genes for AD influence AD biomarkers.
doi:10.1001/archneurol.2011.208
PMCID: PMC3327304  PMID: 21987546
3.  Autobiographical Memory Task in Assessing Dementia 
Archives of neurology  2010;67(7):862-866.
Objective
To appraise the relationship of a task assessing memory for recent autobiographical events and those of two commonly used brief memory tasks with the results of a clinical assessment for dementia.
Design, Setting, and Participants
We compared correlations between a task assessing recall of recent autobiographical events and two frequently-used brief clinical memory measures with dementia ratings by clinicians. Participants were enrolled in Washington University Alzheimer’s Disease Research Center studies, were aged 60 years or above, and took part in assessments between May 2002 and August 2005 (N=425).
Main Outcome Measures
Nonparametric, rank-based Spearman correlations, adjusted for age and education, between the Clinical Dementia Rating Sum of Boxes (CDR-SB) and scores on the autobiographical recall query and two clinical memory tasks taken from the Mini-Mental State Exam and the Short Blessed Test.
Results
The autobiographical recall task and each of the other brief clinical measures correlated significantly with the CDR-SB (p<.0001). The autobiographical recall task had a significantly higher correlation (p<.0001) with the CDR-SB than the two commonly-used clinical memory measures.
Conclusions
Clinicians may find autobiographical memories an important indicator of clinical memory function and the autobiographical query a useful tool when assessing for dementia.
doi:10.1001/archneurol.2010.145
PMCID: PMC2904638  PMID: 20625094
4.  PIB Imaging Predicts Progression from Cognitively Normal to Symptomatic Alzheimer’s Disease 
Archives of neurology  2009;66(12):1469-1475.
Objective
To determine whether preclinical Alzheimer’s disease (AD), as detected by the amyloid imaging agent Pittsburgh Compound B (PIB) in cognitively normal older adults, is associated with risk of symptomatic AD.
Design
A longitudinal cohort study of cognitively normal older adults assessed with positron emission tomography (PET) to determine the mean cortical binding potential for PIB and followed with annual clinical and cognitive assessments for progression to very mild dementia of the Alzheimer type (DAT).
Setting
Alzheimer’s Disease Research Center
Participants
One hundred and fifty-nine participants with mean age of 71.5 y in a longitudinal study of memory and aging had a PET PIB scan when cognitively normal with Clinical Dementia Rating (CDR) of 0.
Outcome Measure
Progression from CDR 0 status to CDR 0.5 (very mild dementia).
Results
Twenty-three participants progressed to CDR 0.5 at follow-up assessment (range: 1–5 assessments after PET PIB). Of these, 9 also were diagnosed with DAT. Higher MCBP values for PIB (hazard ratio 4.85, 95% CI, 1.22–19.01, p = .02) and age (hazard ratio 1.14, 95% CI 1.02–1.28, p = .03) predicted progression to CDR 0.5 DAT. The CDR 0.5 DAT group showed decline in three cognitive domains (episodic memory, semantic memory, and visuospatial performance) and had volume loss in the parahippocampal gyrus (includes entorhinal cortex) compared with individuals who remained CDR 0.
Conclusions
Preclinical AD, as detected by PET PIB, is not benign as it is associated with progression to symptomatic AD.
doi:10.1001/archneurol.2009.269
PMCID: PMC2798814  PMID: 20008650
5.  Stability of the Clinical Dementia Rating: 1979–2007 
Archives of neurology  2009;66(6):773-777.
Background
Diagnostic drift characterizes change in diagnosis and diagnostic classification over time. The Clinical Dementia Rating (CDR) is used commonly in dementia diagnosis and staging of dementia severity. Whether increasing efforts to diagnose dementia at earlier symptomatic stages has led to diagnostic drift in the CDR is unknown.
Objective
To examine dementia severity as determined by the CDR over time.
Design
Secondary analysis of data from longitudinal studies of aging and dementia.
Setting
An Alzheimer’s Disease Research Center (ADRC), where a variety of clinicians contributed CDR ratings over the course of the study.
Participants
Adults aged 63 to 83 years with no (CDR 0), very mild (CDR 0.5) or mild (CDR 1) dementia enrolled in the ADRC at any time from August 1979 to May 2007.
Main Outcome Measures
Within each CDR group changes in scores on standardized psychometric tests with time were examined using multiple linear regression analyses. These tests included the Mini Mental State Examination, Short Blessed Test, Wechsler Memory Scale Logical Memory IA-Immediate, Blessed Dementia Scale, and a psychometric composite score.
Results
A total of 1768 participants met inclusion criteria. Over time, participants were older, more educated, more likely to be minorities, and less likely to be male. Statistically significant change in psychometric test performance over time occurred only within the CDR 1 group for Logical Memory and the psychometric composite, but the degree of change was minimal.
Conclusion
Despite changes in participant characteristics, the CDR demonstrates general stability for assessment of dementia over almost three decades.
doi:10.1001/archneurol.2009.69
PMCID: PMC2779108  PMID: 19506139
6.  Education and Reported Onset of Symptoms among Individuals with Alzheimer’s Disease 
Archives of neurology  2008;65(1):108-111.
Objective
To examine whether reported age at onset (AAO) of dementia symptoms among participants with Alzheimer’s disease (AD) is later for those with fewer years of education and, if so, to see if it is attributed to delayed detection of symptoms.
Design
Case series.
Setting
National Alzheimer’s Coordinating Center Minimum Data Set (N=21,880 participants) and Washington University Alzheimer’s Disease Research Center (N=1,449 participants).
Results
Reported AAO of dementia symptoms is slightly earlier for participants with more education. Participants with fewer years of education show greater clinical severity of AD at first assessment.
Conclusion
Symptoms of AD are recognized later among those with less education.
doi:10.1001/archneurol.2007.11
PMCID: PMC2830808  PMID: 18195147
7.  Alzheimer’s and Cognitive Reserve 
Archives of neurology  2008;65(11):1467-1471.
Objective
To evaluate the cognitive reserve hypothesis by examining whether individuals of greater educational attainment have better cognitive function than individuals with less education in the presence of elevated fibrillar brain amyloid.
Design, Setting, and Participants
Uptake of N-methyl-[11C]2-(4′-methylaminophenyl)-6-hydroybenzothiazole, or [11C]PIB for “Pittsburgh Compound-B,” was measured for participants assessed between August 15, 2003 and January 8, 2008 at the Washington University Alzheimer’s Disease Research Center and diagnosed either as nondemented (N=161) or with dementia of the Alzheimer type (N=37). Multiple regression was used to determine whether [11C]PIB uptake interacted with level of educational attainment to predict cognitive function.
Main Outcome Measures
Scores on the Clinical Dementia Rating - Sum of Boxes (CDR-SB), Mini-Mental State Exam (MMSE), and Short Blessed Test (SBT), and individual measures from a psychometric battery.
Results
[11C]PIB uptake interacted with years of education in predicting scores on the CDR-SB (p=.003), the MMSE (p<.001), the SBT (p=.03) and a measure of verbal abstract reasoning and conceptualization (p=.02), such that performance on these measures increased with increasing education for participants with elevated PIB uptake. Education was unrelated to global cognitive functioning scores among those with lower PIB uptake.
Conclusions
These results support the hypothesis that cognitive reserve influences the association between Alzheimer disease pathology and cognition.
doi:10.1001/archneur.65.11.1467
PMCID: PMC2752218  PMID: 19001165

Results 1-7 (7)