Structural brain differences in the Alzheimer's disease continuum: Insights into the heterogeneity from a large multi-site neuroimaging consortium.

Introduction: Neurodegenerative diseases require collaborative, multi-site research to comprehensively grasp their complex and diverse pathological progression, yet there is caution in aggregating global data due to data heterogeneity. The current study investigates brain structure across stages of Alzheimer's disease (AD), and how relationships vary across sources of heterogeneity.

Methods: Using 6 international datasets(n>27,000), associations of structural neuroimaging markers were investigated in relation to the AD continuum via meta-analysis. We investigated whether associations varied across elements of MRI acquisition, study design and populations.

Results: Modest differences in associations were found dependent on how data were acquired, however patterns were similar. Preliminary results suggest neuroimaging marker-AD relationships differ across ethnic groups.

Discussion: Diversity in data offers unique insights into the neural substrate of AD, however harmonised processing and transparency of data collection is needed. Global collaborations should embrace inherent heterogeneity that exists within the data and quantify its contribution to research findings at the meta-analytical stage.