In Vivo Amyloid, Neurodegeneration, and Verbal Learning in Late Middle-Aged Hispanics

Article type: Research Article

Authors: Tahmi, Mouna^a | Rippon, Brady^a | Palta, Priya^{a; b} | Sherwood, Greysi^a | Hernandez, Gabriela^a | Soto, Luisa^a | Ceballos, Fernando^a | Pardo, Michelle^a | Laing, Krystal^c | Igwe, Kay^c | He, Hengda^f | Teresi, Jeanne A.^g | Moreno, Herman^h | Razlighi, Qolamrezaⁱ | Brickman, Adam M.^{c; d; e} | Luchsinger, José A.^{a; b; *}

Affiliations: [a] Department of Medicine, College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA | [b] Department of Epidemiology, Joseph P. Mailman School of Public Health, Columbia University Irving Medical Center, New York, NY, USA | [c] Department of Neurology, College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA | [d] Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Columbia University Irving Medical Center, New York, NY, USA | [e] Gertrude H. Sergievsky Center, Columbia University Irving Medical Center, New York, NY, USA | [f] Department of Biomedical Engineering, Columbia University, New York, NY, USA | [g] Research Division, Hebrew Home in Riverdale, Bronx, NY, USA | [h] Department of Neurology, SUNY Downstate Medical Center, Brooklyn, NY, USA | [i] Department of Radiology, Weill Cornell Medicine, New York, NY, USA

Correspondence: [*] Correspondence to: Jose A. Luchsinger, Columbia University Irving Medical Center, 622 West 168th Street, PH9 Center room 210, New York, NY 10032, USA. E-mail: ja94@cumc.columbia.edu.

Abstract: Background:The National Institute on Aging (NIA)/Alzheimer’s Association (AA) 2018 framework conceptualizes Alzheimer’s disease (AD) biologically. Evidence of brain amyloid by biomarkers defines AD pathologic change and the Alzheimer’s continuum. The presence of tau or neurodegeneration in the absence of amyloid defines non-AD pathologic change. Objective:To examine the relation of in vivo amyloid and neurodegeneration with verbal learning, one of the cognitive abilities affected early in AD, in late middle age. Methods:This was a cross-sectional study of amyloid and neurodegeneration biomarkers in a community-based cohort of 350 late-middle aged Hispanics without dementia (mean age: 64.15±3.34; 72.0%women). Amyloid (A) was measured as global standardized uptake value ratio (SUVR) with 18F-Florbetaben positron emission tomography (PET). Neurodegeneration (N) was ascertained as cortical thickness (CT) in AD signature areas using brain magnetic resonance imaging. We examined A/N continuously, categorically, by A/N profiles, and profile categories. The amyloid threshold for positivity was defined using the K means method. The CT threshold was defined as 2 standard deviations below the mean CT. Verbal learning was ascertained using total recall and delayed recall in the Buschke Selective Reminding test (SRT). Results:Higher cortical thickness was associated with higher performance in SRT delayed recall. Amyloid SUVR was not related to SRT performance. The low CT category was associated with lower performance in SRT delayed recall, while Amyloid categories were not related to any SRT score. The non-AD pathologic change group (A-N+) performed worse in SRT delayed recall compared to the Normal A/N profile group (A-N-). Conclusion:In late middle-aged Hispanics without dementia, non-AD pathologic change, but not the Alzheimer’s continuum, was related to verbal learning.

Keywords: A/T/(N), amyloid, cognition, Hispanics, neurodegeneration, NIA-AA

DOI: 10.3233/JAD-201304

Journal: Journal of Alzheimer's Disease, vol. 82, no. 1, pp. 317-325, 2021