Objective: We aimed to investigate structural abnormalities in first-episode remitted geriatric depression (RGD) using optimized voxel-based morphometry (VBM) in closely matched patients and healthy controls, and examining the relationship of performances on neuropsychological tests with regional white matter volumes.
Methods: Forty subjects with first-episode RGD and 36 well-matched healthy controls were recruited for this study and neuropsychological tests and magnetic resonance imaging (MRI) were conducted on the subjects. The differences in regional white matter volume were determined between these two groups by optimized VBM.
Results: The white matter volumes of left inferior parietal lobule and right inferior frontal gyrus were significantly larger in patients with RGD relative to healthy controls. RGD patients performed significantly worse in the delayed recall of RAVLT, Trail Making Test A and B (seconds), and Symbol Digit Modalities Test when compared with the control group (all P<0.01). And there was a significant positive correlation between white matter volume of right inferior frontal gyrus and Trail Making Test A (r=0.319, P=0.045) in patients with RGD.
Limitations: This study is cross-sectional, therefore it cannot determine whether increased white matter volume is a state marker or trait marker of RGD.
Conclusion: These results reveal that RGD is associated with larger white matter volumes of left inferior parietal lobule and right inferior frontal gyrus, and the right inferior frontal gyrus may thus be involved in the pathophysiology of executive function in RGD.