Identifying sensitive measures of cognitive decline at different clinical stages of alzheimer's disease

Roos J. Jutten*, Sietske A. M. Sikkes, Rebecca E. Amariglio, Alzheimer Disease Neuroimaging Initiative, Rachel F. Buckley, Michael J. Properzi, Gad A. Marshall, Dorene M. Rentz, National Alzheimer's Coordinating Center, Keith A. Johnson, Harvard Aging Brain Study, Charlotte E. Teunissen, Alzheimer Dementia Cohort, Bart N. M. van Berckel, Wiesje M. van der Flier, Philip Scheltens, Reisa A. Sperling, Kathryn V. Papp

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Objective: Alzheimer's disease (AD) studies are increasingly targeting earlier (pre)clinical populations, in which the expected degree of observable cognitive decline over a certain time interval is reduced as compared to the dementia stage. Consequently, endpoints to capture early cognitive changes require refinement. We aimed to determine the sensitivity to decline of widely applied neuropsychological tests at different clinical stages of AD as outlined in the National Institute on Aging - Alzheimer's Association (NIA-AA) research framework. Method: Amyloid-positive individuals (as determined by positron emission tomography or cerebrospinal fluid) with longitudinal neuropsychological assessments available were included from four well-defined study cohorts and subsequently classified among the NIA-AA stages. For each stage, we investigated the sensitivity to decline of 17 individual neuropsychological tests using linear mixed models. Results: 1103 participants (age = 70.54 ± 8.7, 47% female) were included: n = 120 Stage 1, n = 206 Stage 2, n = 467 Stage 3 and n = 309 Stage 4. Neuropsychological tests were differentially sensitive to decline across stages. For example, Category Fluency captured significant 1-year decline as early as Stage 1 (β = -.58, p < .001). Word List Delayed Recall (β = -.22, p < .05) and Trail Making Test (β = 6.2, p < .05) became sensitive to 1-year decline in Stage 2, whereas the Mini-Mental State Examination did not capture 1- year decline until Stage 3 (β = -1.13, p < .001) and 4 (β = -2.23, p < .001). Conclusions: We demonstrated that commonly used neuropsychological tests differ in their ability to capture decline depending on clinical stage within the AD continuum (preclinical to dementia). This implies that stage-specific cognitive endpoints are needed to accurately assess disease progression and increase the chance of successful treatment evaluation in AD.

Original languageEnglish
JournalJournal of the International Neuropsychological Society
Early online date2020
DOIs
Publication statusE-pub ahead of print - 2020

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