Diffusion tensor imaging of the corticospinal tract and walking performance in multiple sclerosis

Area of Science:

• Neuroimaging
• Neurology
• Biomedical Engineering

Background:

• Multiple Sclerosis (MS) significantly impacts disability and motor function.
• Diffusion Tensor Imaging (DTI) indices of the Corticospinal Tract (CST) are linked to MS disability.
• The relationship between CST DTI indices and specific walking/gait outcomes in MS remains underexplored.

Purpose of the Study:

• To investigate the associations between DTI indices of the CST and walking/gait performance in individuals with MS.
• To explore how white matter integrity in the CST relates to objective measures of walking and gait.

Main Methods:

• Sixty-nine individuals with MS underwent 3T brain MRI for DTI analysis of the CST.
• Participants completed the 6-minute walk (6MW), timed 25-foot walk (T25FW), and detailed gait testing.
• Spearman and partial Spearman correlations were used, controlling for age, sex, and disease duration.

Main Results:

• Radial diffusivity (RD) correlated with step time (pr(s)=0.30).
• Axial diffusivity (AD) correlated with step length (pr(s)=-0.32).
• Mean diffusivity (MD) showed significant associations with 6MW (pr(s)=-0.35), T25FW (pr(s)=-0.34), gait velocity (pr(s)=-0.31), step time (pr(s)=0.29), and step length (pr(s)=-0.36).
• Fractional anisotropy (FA) did not significantly correlate with any walking parameters.

Conclusions:

• Novel evidence suggests motor pathway (CST) damage influences walking performance in MS.
• Subtle differences in associations between MD, AD, and RD with walking outcomes warrant further investigation.
• Findings may inform future longitudinal studies and clinical trials for MS motor rehabilitation.