Effect of diagnostic and genetic status on the relationship between rs-fMRI complexity and tau & amyloid PET in Alzheimer’s disease.

Motivation: Decreased brain function in Alzheimer’s Disease can be assessed by complexity of resting-state fMRI. Specifically, in precuneus and medial temporal lobe rsfMRI-complexity is reduced in MCI and AD and negatively associated with tau-PET uptake. However, its association with amyloid deposition or effects of genetic characteristics (APOE4) remains unknown. Goal(s): To investigate the association between rsfMRI-complexity, tau-PET and amyloid-PET as well as influence of APOE4 status. Approach: Multivariate linear models assessing rsfMRI-complexity, tau-PET, amyloid-PET and APOE4 in select regions of interest. Results: rsfMRI-complexity shows a strong significant inverse relationship with tau but not amyloid and APOE4 increases this effect. Impact: We show that rsfMRI-complexity shows a strong association with tau but not amyloid deposition and that genetic risk in form of APOE4 strengthens this effect. Thus rsfMRI-complexity adds a novel tool to investigate impaired brain functionality in AD progression.