Parkinson’s disease propagation using MRI biomarkers and partial least squares path modeling

Objectives: The classical Braak neuropathological staging model in Parkinson's disease (PD) suggests that brain lesions progress from the medulla oblongata to the cortex. An alternative model in which neurodegeneration first occurs in the cortex has also been proposed. These two models may correspond to different patient phenotypes. To test these two models and investigate if they were influenced by the presence of rapid eye movement sleep behavior disorder (RBD) we used multimodal MRI and Partial Least Squares Path-Modeling (PLS-PM) assuming that patients with RBD followed distinct neurodegeneration pattern.

Methods: Fifty-four patients with PD (thirty-four with RBD) and twenty-five healthy volunteers were scanned using T1-weighted, diffusion tensor and neuromelanin-sensitive imaging. Volume, signal, mean, axial and radial diffusivities were calculated in brainstem, basal forebrain and cortical regions. PLS-PM, estimating a network of causal relationships between blocks of variables...