@article{b91074cffa4e4a6593546f20721e2cca,
title = "Putting the Alzheimer's cognitive test to the test I: Traditional psychometric methods",
abstract = "Background: The Alzheimer's Disease Assessment Scale - Cognitive Behavior section (ADAS-Cog) is the most commonly used cognitive test in AD clinical trials. However, there are concerns about its use in early-stage disease. Herein we examine those concerns using traditional psychometric methods. Methods: We analyzed ADAS-Cog data (n = 675) based on six psychometric properties: data completeness; scaling assumptions; targeting; reliability; validity; and responsiveness. Results: At the scale-level, criteria tested for data completeness, scaling assumptions (item total correlations 0.33-0.59), targeting (no floor/ceiling effects), reliability (Cronbach's α = 0.74), and validity (correlation with MMSE = -0.70) were satisfied. Responsiveness (baseline to 12 months; n = 145) was moderate to high (effect size = -0.73). However, 8 of 11 ADAS-Cog components had substantial ceiling effects (range 32%-83%), and decreased responsiveness associated with low to moderate effect sizes (0.14-0.65). Conclusion: In our study, many patients with AD found large portions of the ADAS-Cog too easy. Future research should consider modifying the ADAS-Cog or developing a new test.",
keywords = "Alzheimer's disease, Clinical trials, Psychometrics, Reliability, Validity",
author = "Jeremy Hobart and Stefan Cano and Holly Posner and Ola Selnes and Yaakov Stern and Ronald Thomas and John Zajicek",
note = "Funding Information: Data collection and sharing for this project was funded by the Alzheimer's Disease Neuroimaging Initiative (ADNI; National Institutes of Health Grant U01 AG024904 ). The ADNI is funded by the National Institute on Aging, the National Institute of Biomedical Imaging and Bioengineering , and through generous contributions from: Abbott Laboratories; the Alzheimer{\textquoteright}s Association; the Alzheimer{\textquoteright}s Drug Discovery Foundation; Amorfix Life Sciences, Ltd.; AstraZeneca; Bayer HealthCare; BioClinica, Inc.; Biogen Idec, Inc.; Bristol-Myers Squibb Co.; Eisai, Inc.; Elan Pharmaceuticals, Inc.; Eli Lilly and Co.; F. Hoffmann-La Roche, Ltd., and its affiliated company Genentech, Inc.; GE Healthcare; Innogenetics, N.V.; Janssen Alzheimer Immunotherapy Research & Development, LLC; Johnson & Johnson Pharmaceutical Research & Development LLC; Medpace, Inc.; Merck & Co., Inc.; Meso Scale Diagnostics, LLC; Novartis Pharmaceuticals Corporation; Pfizer, Inc.; Servier; Synarc, Inc.; and Takeda Pharmaceutical Co . The Canadian Institutes of Health Research is providing funds to support ADNI clinical sites in Canada. Private sector contributions are facilitated by the Foundation for the National Institutes of Health ( www.fnih.org ). The grantee organization is the Northern California Institute for Research and Education, and the study is coordinated by the Alzheimer's Disease Cooperative Study at the University of California, San Diego. ADNI data are disseminated by the Laboratory for Neuroimaging at the University of California, Los Angeles. This research was also supported by the National Institutes of Health ( P30 AG010129 and K01 AG030514 ). Funding Information: This study was supported by grants from an anonymous foundation (to J.H.). Some of J.H., S.C., and J.Z.'s research time was funded by the National Institute for Health Research (NIHR) under its Programme Grants for Applied Research Programme (Grant Reference Number RP-PG-0707-10124). The views expressed in this article are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. The authors thank Teresa Driscoll for editorial assistance with this manuscript. Copyright: Copyright 2018 Elsevier B.V., All rights reserved.",
year = "2013",
month = feb,
doi = "10.1016/j.jalz.2012.08.006",
language = "English (US)",
volume = "9",
pages = "S10--S20",
journal = "Alzheimer's and Dementia",
issn = "1552-5260",
publisher = "Elsevier Inc.",
number = "1 SUPPL.",
}