Cortico-Subcortical White Matter Bundle Changes in Cervical Dystonia and Blepharospasm

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• Dystonia is increasingly recognized as a network disorder involving the basal ganglia-thalamo-cortical circuit.
• Cervical dystonia (CD) and blepharospasm (BSP) are focal forms of dystonia with unclear pathophysiological mechanisms.

Purpose of the Study:

• To investigate white matter (WM) microstructural integrity in specific WM tracts connecting subcortical and cortical regions in CD and BSP patients.
• To compare WM microstructural damage between CD and BSP patients and healthy subjects (HS).

Main Methods:

• Diffusion tensor imaging (DTI) was performed on 35 patients (17 CD, 18 BSP) and 17 HS.
• Probabilistic tractography (BedpostX) reconstructed WM tracts linking the globus pallidus, putamen, and thalamus with motor cortices.
• DTI metrics (mean, radial, axial diffusivity) evaluated WM tract integrity.

Main Results:

• Significant differences in DTI metrics were found in most reconstructed WM tracts between CD patients and HS.
• Significant differences in DTI metrics were also observed between BSP patients and HS.
• No significant differences in WM tract integrity were found between CD and BSP patient groups.

Conclusions:

• Abnormalities in DTI metrics of specific WM tracts suggest diffuse and extensive WM integrity loss in both CD and BSP.
• These findings support a common pathophysiological mechanism involving microstructural damage within the basal ganglia-thalamo-cortical circuit in focal dystonia.