Photo Credit: Kateryna Kon

The following is a summary of “Spatiotemporal neurodegeneration of the substantia nigra and its connecting cortex and subcortex in Parkinson’s disease,” published in the November 2024 issue of Neurology by Wen et al.    

Neurodegeneration in Parkinson’s disease (PD) is uneven, affecting various brain regions differently.  

Researchers conducted a prospective study to explore spatiotemporal neurodegeneration in the substantia nigra (SN) and the connected brain regions in people with PD.  

They enrolled 120 patients with early-stage PD, 45 with advanced PD, and 120 HCs. The SN, cortex, and subcortex were divided into sensorimotor, associative, and limbic regions. Iron deposition in the SN was assessed using quantitative susceptibility mapping (QSM), and the cortex and subcortex volumes were calculated from T1-weighted imaging (T1WI). Region of interest (ROI) analysis and voxel-based analysis (VBA) were conducted to examine spatiotemporal neurodegeneration in PD, and P-values were adjusted for false discovery rate (FDR).  

The results showed higher QSM values in the limbic (P=0.018) and sensorimotor (P=0.018) SN subregions of patients with PD compared to HCs, but no difference in the associative SN subregion (P=0.295). In VBA, all SN subregions showed higher QSM values in patients with PD (P<0.001). Iron deposition in the limbic SN subregion increased from early-stage to advanced PD (P=0.023). The QSM values in the VBA limbic, sensorimotor, and associative SN subregions correlated with disease severity (P=0.001 for limbic and sensorimotor, P=0.003 for associative), motor symptoms (P=0.057 for limbic and sensorimotor), and depression scores (P=0.036 for limbic).  

They concluded that iron deposition and atrophy in the SN and connected brain regions showed spatiotemporal selectivity, revealing insights into clinical variability in PD.  

Source: onlinelibrary.wiley.com/doi/full/10.1111/ene.16546