Structural changes in early-stage Parkinson's disease with resting tremor at node, edge and network level

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• Resting tremor in Parkinson's disease (PD) is associated with basal ganglia and cerebello-thalamo-cortical network activity.
• Previous insights primarily derive from functional MRI, with limited structural studies available to support these findings.

Purpose of the Study:

• To investigate structural alterations within the cerebello-thalamo-cortical network in Parkinson's disease patients experiencing resting tremor (PD-WR).
• To compare structural network differences between PD-WR, PD patients without resting tremor (PD-NR), and healthy controls (HC).

Main Methods:

• Structural MRI analysis was conducted on 42 early-stage PD-WR patients, 27 PD-NR patients, and 56 healthy controls.
• Cortical thickness, fractional anisotropy (FA), and diffusivity metrics were assessed.
• Network-level properties including hierarchy, small-worldness, and nodal involvement were analyzed and correlated with tremor amplitude.

Main Results:

• PD-WR patients exhibited reduced cortical thickness in motor-related lobules (VIIA, VI, V) compared to HC and PD-NR groups.
• Increased FA in cerebello-cortical connections and reduced radial/mean diffusivity were observed in PD-WR versus PD-NR.
• Network analysis showed positive correlations between tremor amplitude and hierarchy, small-worldness, and thalamic/motor cortex nodal involvement.

Conclusions:

• The findings support the involvement of the cerebello-thalamo-cortical circuit in PD with resting tremor.
• Further research with diverse PD forms, disease stages, and larger cohorts is warranted to fully elucidate these structural changes.