Performance in information processing speed is associated with parietal white matter tract integrity in multiple...

Area of Science:

• Neuroscience
• Radiology
• Neurology

Background:

• The Symbol Digit Modalities Test (SDMT) is a key measure for processing speed in multiple sclerosis (MS).
• Functional imaging highlights frontal and parietal regions in MS task performance.
• The role of frontoparietal white matter tracts in MS processing speed remains understudied.

Purpose of the Study:

• To investigate tract-specific characteristics of frontoparietal white matter.
• To determine the association between these tract characteristics and processing speed in MS patients.

Main Methods:

• Diffusion tensor imaging (DTI) was used in 100 MS patients and 24 controls.
• Tract characteristics were analyzed for the superior parietal lobule (Brodman area 7A - BA7A), superior longitudinal fasciculus (SLF), and corticospinal tract (CST).
• Association with SDMT performance was assessed.

Main Results:

• MS patients showed reduced SDMT performance and white matter volume.
• Fractional anisotropy (FA) differed in BA7A and CST tracts between MS patients and controls.
• SLF FA positively correlated with SDMT performance, even after lesion exclusion.

Conclusions:

• Processing speed in MS is associated with the structural integrity of frontoparietal white matter tracts.
• Specific white matter tracts, like the SLF, play a role in maintaining cognitive function in MS.