White matter involvement in idiopathic Parkinson disease: a diffusion tensor imaging study

Area of Science:

• Neuroimaging
• Neurology
• Biomedical Engineering

Background:

• Parkinson disease (PD) is associated with cognitive symptoms linked to connectivity changes.
• Diffusion Tensor Imaging (DTI) is a neuroimaging technique that can reveal microstructural alterations in the brain's white matter.

Purpose of the Study:

• To assess microstructural damage in the cerebral white matter of patients with idiopathic Parkinson disease.
• To investigate white matter connectivity changes beyond the basal ganglia in early-stage PD.

Main Methods:

• DTI scans were performed on patients with early-stage PD (Hoehn and Yahr stages I-II, no dementia) and age-matched healthy controls.
• Mean diffusivity (MD) and fractional anisotropy (FA) maps were generated.
• Regions of interest (ROIs) were defined on major white matter fiber bundles and deep gray matter nuclei.

Main Results:

• Increased MD was observed in the genu of the corpus callosum and superior longitudinal fasciculus, with decreased FA in these areas.
• Altered MD was found in the cingulum, while FA remained unchanged.
• No significant microstructural changes (MD or FA) were detected in the corticospinal tract, corpus callosum splenium, or basal ganglia nuclei (thalamus, globus pallidus, putamen, caudate).

Conclusions:

• Early-stage Parkinson disease is characterized by widespread microstructural damage in frontal and parietal white matter.
• These findings suggest that white matter integrity is compromised early in the course of PD, potentially contributing to cognitive deficits.