Morphometric changes of gray matter in Parkinson's disease with depression: a voxel-based morphometry study

Area of Science:

• Neuroscience
• Neurology
• Psychiatry

Background:

• Idiopathic Parkinson's disease (PD) is frequently associated with a high incidence of depression.
• The underlying neurobiological mechanisms contributing to depression in PD remain largely unknown.

Purpose of the Study:

• To investigate structural brain differences, specifically gray matter density alterations, between depressed and nondepressed individuals with idiopathic Parkinson's disease.
• To identify brain regions associated with depressive symptoms in Parkinson's disease patients.

Main Methods:

• Voxel-based morphometry (VBM) was employed to detect gray matter density differences.
• Patients with idiopathic PD were categorized into depressed (DPD) and nondepressed (NDPD) groups using the Montgomery-Asberg Depression Rating Scale (MADRS).
• Group comparisons included DPD (n=23), NDPD (n=27), and normal healthy controls (NC, n=16).

Main Results:

• No significant gray matter density differences were observed between healthy controls and either PD group.
• Depressed PD patients (DPD) exhibited reduced gray matter density in the bilateral orbitofrontal cortex, bilateral rectal gyrus, and the right superior temporal pole compared to nondepressed PD patients (NDPD).
• Exploratory analyses revealed an inverse correlation between MADRS scores and the severity of VBM alterations in these regions, as well as the right medial temporal gyrus, anterior and medial cingular gyrus, and parahippocampal gyrus.

Conclusions:

• Depression in Parkinson's disease is associated with gray matter volume reduction in specific brain areas.
• The findings implicate the orbitofrontal cortex, temporal regions, and limbic system structures in the pathophysiology of depression within the PD population.