Preserved brain adaptive properties in patients with benign multiple sclerosis.

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• Multiple sclerosis (MS) presents diverse clinical trajectories, including benign (BMS) and secondary progressive (SPMS) forms.
• Understanding motor network function differences is crucial for predicting MS disease progression and clinical outcomes.

Purpose of the Study:

• To investigate and contrast motor network function between patients with BMS, SPMS, and healthy controls (HC).
• To identify factors associated with a favorable clinical evolution in MS.

Main Methods:

• Acquisition of diffusion tensor (DT) and functional MRI (fMRI) scans during a motor task in 17 BMS, 15 SPMS patients, and 17 HC.
• Analysis of normal-appearing white matter (NAWM) and gray matter (GM) using DT MRI histograms.
• fMRI data analyzed using SPM5 to assess brain activation patterns.

Main Results:

• Both BMS and SPMS groups exhibited increased primary sensorimotor cortex activation compared to HC.
• SPMS patients showed additional widespread cortical and subcortical alterations, including reduced activation in motor areas like the supplementary motor area, putamen, and cerebellum.
• fMRI changes in MS patients correlated with T2 lesion volume and DT MRI metrics in NAWM and GM.

Conclusions:

• Motor network activation in BMS is largely preserved, resembling HC, with abnormalities confined to the sensorimotor network.
• In contrast, SPMS demonstrates more extensive functional reorganization and deficits.
• Preserved brain functional adaptation mechanisms in BMS likely underlie their favorable clinical course.