The association between white matter tract structural connectivity and information processing speed in...

Area of Science:

• Neuroimaging
• Neurology
• Cognitive Neuroscience

Background:

• Information processing speed (IPS) decline is prevalent in relapsing-remitting multiple sclerosis (RRMS) patients, impacting daily life.
• The precise neural underpinnings of IPS deficits in RRMS remain incompletely understood.

Purpose of the Study:

• To investigate the relationship between MRI-derived neuroanatomical metrics and IPS in RRMS patients.
• To identify specific white matter tracts and gray matter structures associated with IPS impairment.

Main Methods:

• Evaluated IPS using Symbol Digit Modalities Test (SDMT), Paced Auditory Serial Addition Test (PASAT), and Color Trails Test (CTT) in 73 RRMS patients on interferon beta (IFN-β) therapy.
• Acquired 1.5T MRI including diffusion tensor imaging (DTI) data.
• Analyzed volumetric (Normalized Brain Volume, cortical thickness, white matter hypointensities, thalamic volume) and diffusion (mean, radial, axial diffusivity; fractional anisotropy) MRI measures for 18 major white matter tracts using FreeSurfer 6.0.

Main Results:

• Significant associations between IPS deficit and white matter tract abnormalities, including fractional anisotropy (FA) in the right inferior longitudinal fasciculus (R ILF), forceps major (FMAJ), forceps minor (FMIN), right corticospinal tract (R CST), and left superior longitudinal fasciculus (L SLFT), as well as axial diffusivity (AD) in the right uncinate fasciculus (R UNC).
• IPS deficits were also correlated with reduced left and right thalamic volume and decreased cortical thickness in insular regions.

Conclusions:

• Disconnection of specific white matter tracts, alongside cortical and deep gray matter atrophy, likely contributes to IPS deficits in RRMS.
• Further extensive research is required to precisely delineate these associations.