Progressive microstructural changes of the occipital cortex in Huntington's disease

Area of Science:

• Neuroimaging
• Neurodegeneration
• Diffusion MRI

Background:

• Huntington's disease (HD) is a progressive neurodegenerative disorder.
• Early detection of microstructural changes is crucial for monitoring disease progression.
• The occipital cortex's role in early HD stages requires further investigation.

Purpose of the Study:

• To longitudinally assess microstructural alterations in the occipital cortex across HD stages.
• To identify potential biomarkers for tracking disease progression and therapeutic interventions.

Main Methods:

• Longitudinal diffusion MRI scans were acquired from 22 premanifest HD (preHD), 10 early HD, and 24 control subjects over two years.
• An automated atlas-based approach analyzed diffusion tensor imaging (DTI) data to measure diffusivity changes in occipital regions.
• PreHD participants were stratified into 'far' (preHD-A) and 'near' (preHD-B) to disease onset groups.

Main Results:

• Early HD subjects showed significantly higher rates of diffusivity change in the superior, middle, and inferior occipital gyri compared to preHD and controls.
• The rate of diffusivity change in the middle occipital gyrus (MOG) differentiated preHD-B from preHD-A and controls.
• An inverse correlation was observed between Stroop Word Reading task performance and occipital diffusivity in preHD and early HD groups.

Conclusions:

• Occipital cortex microstructural changes, detectable via DTI, are sensitive longitudinal biomarkers for HD progression.
• These findings highlight the potential of occipital DTI measures for evaluating disease-modifying therapies in preHD-B and early HD.
• The MOG's diffusivity change rate may serve as a specific indicator for individuals nearing HD onset.