Vol. 27, No. 4, 2009
Issue release date: April 2009
Free Access
Dement Geriatr Cogn Disord 2009;27:344–352
(DOI:10.1159/000209212)
Original Research Article
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Agreement in Cognitive and Clinical Assessments in Alzheimer’s Disease

Tractenberg R.E.a, b · Aisen P.S.b
aDepartments of Neurology, Biostatistics, Bioinformatics and Biomathematics, and Psychiatry, Georgetown University School of Medicine, Washington, D.C., and bDepartment of Neurology, University of California, San Diego, La Jolla, Calif., USA
email Corresponding Author


 goto top of outline Key Words

  • Alzheimer’s disease
  • Dementia
  • Outcomes assessment methods

 goto top of outline Abstract

Aims: To estimate agreement among scores on three common assessments of cognitive function. Method: Baseline responses on the Alzheimer’s Disease Assessment Scale – Cognitive, Clinical Dementia Rating, and the Mini-Mental State Examination were obtained from two clinical trials (n = 138 and n = 351). A graphical method of examining agreement, the means-difference or Bland-Altman plot, was followed by Levene’s test of the equality of variance corrected for multiple comparison within each sample. Results: 70–78% of variability was shared by one factor, suggesting that all three instruments reflect cognitive impairment. However, agreement among tests was significantly worse for individuals with greater-than-average, relative to individuals with less-than-average, cognitive impairment. Conclusions: Worse agreement between tests, as a function of increasing cognitive impairment, implies that interpretation of these tests and selection of coprimary cognitive impairment outcomes may depend on impairment level.

Copyright © 2009 S. Karger AG, Basel


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 goto top of outline Author Contacts

Rochelle E. Tractenberg
Georgetown University School of Medicine
Collaborative for Research on Outcomes and -Metrics
Building D, Suite 207, 4000 Reservoir Rd. NW, Washington, DC 20057 (USA)
Tel. +1 202 444 8748, Fax +1 202 444 4114, E-Mail ret7@georgetown.edu


 goto top of outline Article Information

Accepted: October 20, 2008
Published online: March 17, 2009
Number of Print Pages : 9
Number of Figures : 3, Number of Tables : 1, Number of References : 32


 goto top of outline Publication Details

Dementia and Geriatric Cognitive Disorders

Vol. 27, No. 4, Year 2009 (Cover Date: April 2009)

Journal Editor: Chan-Palay V. (New York, N.Y.)
ISSN: 1420-8008 (Print), eISSN: 1421-9824 (Online)

For additional information: http://www.karger.com/DEM


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