Spatial representation of the statistically significant longitudinal changes of deformations in the Thalamus surface of PD subjects. The negative sign effects correspond to an inward deformation change along the surface’s normal. Those changes become stronger and more spatially extended over time, providing a local quantitative assessment of atrophy progression.
A mixed-effects longitudinal model was fitted to the surface deformation data to assess the main effect of change over time for each of the groups under study, namely, Controls, Prodromal and PD.
After correction for multiple comparisons using a False Discovery Rate (FDR) approach, statistically significant longitudinal effects in local surface deformations of the Thalamus were detected in PD subjects. Most of those significant changes reflected an inward displacement along the surface’s normal, providing a local assessment of atrophy progression. The significant changes of deformations relative to the baseline time point appeared to become stronger and more spatially extended over time.