College of Psychology: Faculty Articles

Title

Reliability and Validity of an Algorithm for the Diagnosis of Normal Cognition, Mild Cognitive Impairment, and Dementia: Implications for Multicenter Research Studies

Document Type

Article

Publication Date

4-2010

Keywords

Diagnosis, Algorithmic Diagnosis, Mild Cognitive Impairment, Dementia, Longitudinal Studies

Publication Title

The American Journal of Geriatric Psychiatry

ISSN

1064-7481

Volume

18

Issue/No.

4

Abstract

METHODS:

The AlgDx combines the PhyDx with the NPDx, using a diagnostic algorithm that provides cognitive diagnoses, as defined by the National Alzheimer Coordinating Center/Uniform Data Set nomenclature. Reliability of the AlgDx was assessed in 532 community-dwelling elderly subjects by its concordance with the ConsDx and association with two biomarkers, medial temporal atrophy (MTA) scores of brain magnetic resonance imaging scans, and Apolipoprotein E (ApoE)-epsilon4 genotype.

RESULTS:

A high degree of concordance was observed between ConsDx and AlgDx with a weighted Cohen's kappa of 0.84. Concordance of the AlgDx to the same ConsDx categories ranged from 85% to 92%. Excellent discriminative validity was observed using AlgDx, MTA scores, and ApoE-epsilon4 allele frequencies, each of which distinguished subjects with amnestic MCI and dementia from normal subjects.

CONCLUSION:

The AlgDx of normal cognition, MCI, and dementia is a valid alternative that reduces time, effort, and biases associated with the ConsDx. The inherent reliability of a fixed algorithm, together with its efficiency and avoidance of individual bias, suggests the AlgDx may be used in longitudinal, multisite clinical trials, and population studies of MCI and dementia.

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