Functional connectivity in multiple sclerosis modelled as connectome stability: A 5-year follow-up study

Area of Science:

• Neuroimaging
• Neurology
• Medical Science

Background:

• Multiple sclerosis (MS) is characterized by abnormal brain functional connectivity (FC) compared to healthy controls (HCs).
• Longitudinal studies are crucial to assess the clinical relevance of FC stability in MS.

Purpose of the Study:

• Compare functional magnetic resonance imaging (fMRI)-based FC between MS patients and HCs.
• Investigate the relationship between longitudinal FC changes and structural brain damage, cognitive performance, and physical disability in MS.

Main Methods:

• Acquired T1-weighted MPRAGE and resting-state fMRI data from 70 MS patients and 94 HCs at baseline, with follow-up fMRI for 60 MS patients after 5 years.
• Utilized independent component analysis and network modeling for longitudinal FC stability assessment and cross-sectional comparisons.
• Employed linear mixed models to correlate FC changes with clinical and imaging metrics, adjusting for age and sex.

Main Results:

• MS patients exhibited baseline FC abnormalities within networks and in specific connections compared to HCs.
• Longitudinal analysis indicated functional stability in FC over the 5-year period.
• No significant correlations were found between FC stability and clinical disability, cognitive function, lesion load, or brain volume.

Conclusions:

• Functional connectivity abnormalities are present early in MS, within the first decade.
• Despite early abnormalities, FC stability over 5 years showed no significant clinical relevance in this cohort.
• Further large-scale longitudinal fMRI studies are needed to explore MS subtypes and diverse outcomes.