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Updated: Aug 29, 2026

Generalized Psychophysiological Interaction (PPI) Analysis of Memory Related Connectivity in Individuals at Genetic Risk for Alzheimer's Disease
Published on: November 14, 2017
Adjusting for non-ignorable verification bias in clinical studies for Alzheimer's disease
Xiao-Hua Zhou1, Pete Castelluccio
1Department of Biostatistics, University of Washington, F600 HSB Box # 357232, Seattle, WA 98195-7232, USA. azhou@u.washington.edu
Abstract:
A common problem for comparing the relative accuracy of two screening tests for Alzheimer's disease (AD) in a two-stage design study is verification bias. If the verification bias can be assumed to be ignorable, Zhou and Higgs have proposed a maximum likelihood approach to compare the relative accuracy of screening tests in a two-stage design study. However, if the verification mechanism also depends on the unobserved disease status, the ignorable assumption does not hold. In this paper, we discuss how to use a profile likelihood approach to compare the relative accuracy of two screening tests for AD without assuming the ignorable verification bias mechanism.
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