Publication date: December 2019
Source: Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring, Volume 11
Author(s): Erin M. Jonaitis, Rebecca L. Koscik, Lindsay R. Clark, Yue Ma, Tobey J. Betthauser, Sara E. Berman, Samantha L. Allison, Kimberly D. Mueller, Bruce P. Hermann, Carol A. Van Hulle, Bradley T. Christian, Barbara B. Bendlin, Kaj Blennow, Henrik Zetterberg, Cynthia M. Carlsson, Sanjay Asthana, Sterling C. Johnson
Abstract
Introduction
Longitudinal cohort studies of cognitive aging must confront several sources of within-person variability in scores. In this article, we compare several neuropsychological measures in terms of longitudinal error variance and relationships with biomarker-assessed brain amyloidosis (Aβ).
Methods
Analyses used data from the Wisconsin Registry for Alzheimer’s Prevention. We quantified within-person longitudinal variability and age-related trajectories for several global and domain-specific composites and their constituent scores. For a subset with cerebrospinal fluid or amyloid positron emission tomography measures, we examined how Aβ modified cognitive trajectories.
Results
Global and theoretically derived composites exhibited lower intraindividual variability and stronger age × Aβ interactions than did empirically derived composites or raw scores from single tests. For example, the theoretical executive function outperformed other executive function scores on both metrics.
Discussion
These results reinforce the need for careful selection of cognitive outcomes in study design, and support the emerging consensus favoring composites over single-test measures.