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Recommended cognitive outcomes in preclinical Alzheimer’s
disease – Consensus statement from the European Prevention
of Alzheimer’s Dementia

“Regional associations of white matter hyperintensities and early cortical amyloid pathology”

Authors: Luigi Lorenzini, Loes T Ansems, Isadora Lopes Alves, Silvia Ingala, David Vállez García, Jori Tomassen, Carole Sudre, Gemma Salvadó, Mhnaz Shekari, Gregory Operto, Anna Brugulat-Serrat, Gonzalo Sánchez-Benavides, Mara ten Kate, Betty Tijms, Alle Meije Wink, Henk J M M Mutsaerts, Anouk den Braber, Pieter Jelle Visser, Bart N M van Berckel, Juan Domingo Gispert, Frederik Barkhof, Lyduine E Collij, the AMYPAD consortium, the EPAD consortium, ALFA cohort

Abstract:

White matter hyperintensities (WMHs) have a heterogeneous aetiology, associated with both vascular risk factors and amyloidosis due to Alzheimer’s disease. While spatial distribution of both amyloid and WM lesions carry important information for the underlying pathogenic mechanisms, the regional relationship between these two pathologies and their joint contribution to early cognitive deterioration remains largely unexplored.

We included 662 non-demented participants from three Amyloid Imaging to Prevent Alzheimer’s disease (AMYPAD)-affiliated cohorts: EPAD-LCS (N = 176), ALFA+ (N = 310), and EMIF-AD PreclinAD Twin60++ (N = 176). Using PET imaging, cortical amyloid burden was assessed regionally within early accumulating regions (medial orbitofrontal, precuneus, and cuneus) and globally, using the Centiloid method. Regional WMH volume was computed using Bayesian Model Selection. Global associations between WMH, amyloid, and cardiovascular risk scores (Framingham and CAIDE) were assessed using linear models. Partial least square (PLS) regression was used to identify regional associations. Models were adjusted for age, sex, and APOE-e4 status. Individual PLS scores were then related to cognitive performance in 4 domains (attention, memory, executive functioning, and language).

While no significant global association was found, the PLS model yielded two components of interest. In the first PLS component, a fronto-parietal WMH pattern was associated with medial orbitofrontal–precuneal amyloid, vascular risk, and age. Component 2 showed a posterior WMH pattern associated with precuneus-cuneus amyloid, less related to age or vascular risk. Component 1 was associated with lower performance in all cognitive domains, while component 2 only with worse memory.

In a large pre-dementia population, we observed two distinct patterns of regional associations between WMH and amyloid burden, and demonstrated their joint influence on cognitive processes. These two components could reflect the existence of vascular-dependent and -independent manifestations of WMH-amyloid regional association that might be related to distinct primary pathophysiology.

DOI: 10.1093/braincomms/fcac150

Published online: 15 June 2022 in the journal Brain communications

Research participants as collaborators: Background,
experience and policies from the PREVENT Dementia and
EPAD programmes

Secondary prevention of Alzheimer’s dementia:
neuroimaging contributions

“Self-reported diabetes is associated with allocentric spatial processing in the European Prevention of Alzheimer’s Dementia Longitudinal Cohort Study”

Authors: Sarah Gregory, Kaj Blennow, Natalie Z. M. Homer, Craig W. Ritchie, Graciela Muniz-Terrera

Abstract:

Type 2 diabetes is a robust predictor of cognitive impairment. Impairment in allocentric processing may help identify those at increased risk for Alzheimer’s disease dementia. The objective of this study was to investigate the performance of participants with and without diabetes on a task of allocentric spatial processing. This was a cross-sectional secondary data analysis study using baseline data from the European Prevention of Alzheimer’s Dementia Longitudinal Cohort Study (EPAD LCS). Participants were aged 50 years and above and were free of dementia at baseline. Participants with no missing data on the variables of interest were included in this study. Our exposure variable was diabetes reported in the medical history. Our primary outcome was the Four Mountains Test (4MT), a novel task of allocentric processing. Covariates included demographics (age, sex, family history of dementia and years of education), APOEε4 carrier status, cognitive status (Clinical Dementia Rating scale), cerebrospinal fluid phosphorylated tau and amyloid-beta 1-42. Of 1324 participants (mean age = 65.95 (±7.45)), 90 had diabetes. Participants with diabetes scored 8.32 (±2.32) on the 4MT compared with 9.24 (±2.60) for participants without diabetes. In a univariate model, diabetes was significantly associated with worse 4MT total scores (β = -.92, p = .001), remaining significant in a fully adjusted model (β = -.64, p = .01). Cerebrospinal fluid phosphorylated tau was significantly higher in participants with diabetes compared with those without. Novel cognitive tests, such as the 4MT, may be appropriate to identify early cognitive changes in this high-risk group. Identifying those at greatest risk for future neurodegeneration is key to prevention efforts.

DOI: doi.org/10.1111/ejn.15821

Published online: 14 September 2022 in the European Journal of Neuroscience

The European Prevention of Alzheimer’s Dementia
(EPAD) Longitudinal Cohort Study: Baseline Data
Release V500.0

The influence of diversity on the measurement of functional
impairment: An international validation of the Amsterdam
IADL Questionnaire in eight countries

“The Open-Access European Prevention of Alzheimer’s Dementia (EPAD) MRI dataset and processing workflow”

Authors: Luigi Lorenzini,Silvia Ingala, Alle Meije Wink, Joost P.A. Kuijer, Viktor Wottschel, Mathijs Dijsselhof, Carole H. Sudre, Sven Haller, Jose Luis Molinuevo, Juan Domingo Gispert, David M. Cash, David L. Thomas, Sjoerd B. Vos, Ferran Prados, Jan Petr, Robin Wolz, Alessandro Palombit, Adam J. Schwarz Gael Chetelat, Pierre Payoux, Carol Di Perri, Joanna M. Wardlaw, Giovanni B. Frisoni, Christopher Foley, Nick C. Fox, Craig Ritchie, Cyril Pernet, Adam Waldman, Frederik Barkhof, Henk J.M.M. Mutsaerts

Abstract:

The European Prevention of Alzheimer Dementia (EPAD) is a multi-center study that aims to characterize the preclinical and prodromal stages of Alzheimer’s Disease. The EPAD imaging dataset includes core (3D T1w, 3D FLAIR) and advanced (ASL, diffusion MRI, and resting-state fMRI) MRI sequences. Here, we give an overview of the semi-automatic multimodal and multisite pipeline that we developed to curate, preprocess, quality control (QC), and compute image-derived phenotypes (IDPs) from the EPAD MRI dataset. This pipeline harmonizes DICOM data structure across sites and performs standardized MRI preprocessing steps. A semi-automated MRI QC procedure was implemented to visualize and flag MRI images next to site-specific distributions of QC features – i.e. metrics that represent image quality. The value of each of these QC features was evaluated through comparison with visual assessment and step-wise parameter selection based on logistic regression. IDPs were computed from 5 different MRI modalities and their sanity and potential clinical relevance were ascertained by assessing their relationship with biological markers of aging and dementia. The EPAD v1500.0 data release encompassed core structural scans from 1356 participants 842 fMRI, 831 dMRI, and 858 ASL scans. From 1356 3D T1w images, we identified 17 images with poor quality and 61 with moderate quality. Five QC features – Signal to Noise Ratio (SNR), Contrast to Noise Ratio (CNR), Coefficient of Joint Variation (CJV), Foreground-Background energy Ratio (FBER), and Image Quality Rate (IQR) – were selected as the most informative on image quality by comparison with visual assessment. The multimodal IDPs showed greater impairment in associations with age and dementia biomarkers, demonstrating the potential of the dataset for future clinical analyses.

DOI: 10.1016/j.nicl.2022.103106

Published online: 7 July 2022 in the Journal NeuroImage: Clinical

The Rationale Behind the New Alzheimer’s Disease
Conceptualization: Lessons Learned During the Last
Decades