An exploratory study of altered regional homogeneity in Parkinson's disease with depression

Depression is a prevalent non-motor symptom in Parkinson's disease (PD), yet its pathogenesis is unclear and biomarkers are lacking. This rs-fMRI study used Regional Homogeneity (ReHo) to explore neural correlates in PD with depression (DPD).

We included 23 DPD, 24 non-depressed PD (NDPD), and 20 healthy controls (HC). ReHo analysis was applied to identify regional brain activity differences. Correlations between ReHo values and depression severity (HAMD scores) were examined. ROC analysis assessed the diagnostic utility of ReHo changes.

Compared to NDPD, DPD showed increased ReHo in the left inferior temporal gyrus (ITG) and decreased ReHo in the right middle frontal gyrus (MFG), left insula, and left hippocampus. ReHo in left ITG positively correlated with HAMD scores (r = 0.4347, P = 0.0023), while right MFG (r = -0.5262, P = 0.0001), left insula, and left hippocampus (r = -0.4049, P = 0.0048) showed negative correlations. ROC analysis indicated that ReHo in the left insula and hippocampus could distinguish DPD (AUC = 0.8062).

DPD is associated with distinct ReHo alterations. Abnormalities in the left ITG, right MFG, left insula, and left hippocampus may reflect the neural basis of DPD. Our exploratory analyses suggest that altered ReHo in the left insula and left hippocampus may hold potential as neuroimaging biomarkers.