Phase synchronization between task-positive and task-negative brain networks using Hilbert Huang Transform for Alzheimer’s disease

Motivation: Resting-state fMRI studies of brain network connectivity have primarily focused on linear, frequency-independent relationships. Goal(s): The primary goal of this study is to quantify the synchronization between brain regions using instantaneous phase information and evaluate their relationship with amyloid deposition in the brain. Approach: Empirical Mode Decomposition (EMD) is utilized to investigate differences in phase synchronization between task-positive and task-negative brain networks across amyloid positive cognitively normal (CN), mild cognitive impairment (MCI) and Alzheimer's disease (AD) patients. Results: A decreased phase synchronization was observed in MCI and AD patients compared to CN. CN and MCI exhibited opposite relationships with amyloid deposition. Impact: Phase synchronization via EMD offers brain connectivity analysis with higher temporal resolution and frequency specificity. It could track network disruptions during disease progression. It could also highlight the influence on amyloid deposition, revealing insights on pathophysiology mechanisms involved in AD.