Association of Pathologic and Volumetric Biomarker Changes With Cognitive Decline in Clinically Normal Adults: Harvard Aging Brain Study

Bernard J Hanseeuw*, Heidi I Jacobs, Aaron P Schultz, Rachel F Buckley, Michelle E Farrell, Nicolas J Guehl, John A Becker, Michael Properzi, Justin S Sanchez, Yakeel T Quiroz, Patrizia Vannini, Jorge Sepulcre, Hyun-Sik Yang, Jasmeer P Chhatwal, Jennifer Gatchel, Gad A Marshall, Rebecca Amariglio, Kathryn Papp, Dorene M Rentz, Marc NormandinJulie C Price, Brian C Healy, Georges El Fakhri, Reisa A Sperling, Keith A Johnson

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Background and ObjectivesHippocampal volume (HV) atrophy is a well-known biomarker of memory impairment. However, compared with β-amyloid (Aβ) and tau imaging, it is less specific for Alzheimer disease (AD) pathology. This lack of specificity could provide indirect information about potential copathologies that cannot be observed in vivo. In this prospective cohort study, we aimed to assess the associations among Aβ, tau, HV, and cognition, measured over a 10-year follow-up period with a special focus on the contributions of HV atrophy to cognition after adjusting for Aβ and tau.MethodsWe enrolled 283 older adults without dementia or overt cognitive impairment in the Harvard Aging Brain Study. In this report, we only analyzed data from individuals with available longitudinal imaging and cognition data. Serial MRI (follow-up duration 1.3-7.0 years), neocortical Aβ imaging on Pittsburgh Compound B PET scans (1.9-8.5 years), entorhinal and inferior temporal tau on flortaucipir PET scans (0.8-6.0 years), and the Preclinical Alzheimer Cognitive Composite (3.0-9.8 years) were prospectively collected. We evaluated the longitudinal associations between Aβ, tau, volume, and cognition data and investigated sequential models to test the contribution of each biomarker to cognitive decline.ResultsWe analyzed data from 128 clinically normal older adults, including 72 (56%) women and 56 (44%) men; median age at inclusion was 73 years (range 63-87). Thirty-four participants (27%) exhibited an initial high-Aβ burden on PET imaging. Faster HV atrophy was correlated with faster cognitive decline (R2 = 0.28, p < 0.0001). When comparing all biomarkers, HV slope was associated with cognitive decline independently of Aβ and tau measures, uniquely accounting for 10% of the variance. Altogether, 45% of the variance in cognitive decline was explained by combining the change measures in the different imaging biomarkers.DiscussionIn older adults, longitudinal hippocampal atrophy is associated with cognitive decline, independently of Aβ or tau, suggesting that non-AD pathologies (e.g., TDP-43, vascular) may contribute to hippocampal-mediated cognitive decline. Serial HV measures, in addition to AD-specific biomarkers, may help evaluate the contribution of non-AD pathologies that cannot be measured otherwise in vivo.

Original languageEnglish
Pages (from-to)e2533-e2544
Number of pages12
JournalNeurology
Volume101
Issue number24
Early online date15 Nov 2023
DOIs
Publication statusPublished - 12 Dec 2023

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