Multiple sclerosis impairs regional functional connectivity in the cerebellum

Area of Science:

• Neuroimaging
• Neurology
• Brain Connectivity

Background:

• Multiple sclerosis (MS) is known to affect long-range brain connectivity.
• Local-level functional brain connectivity alterations in MS remain understudied.

Purpose of the Study:

• To investigate local functional brain connectivity using resting-state functional magnetic resonance imaging (rs-fMRI) in patients with MS.
• To examine the relationship between local connectivity, MS lesion load, and clinical disability.

Main Methods:

• Whole-brain rs-fMRI was performed on 42 MS patients and 30 healthy controls at 3T.
• Kendall's Coefficient of Concordance was used to calculate regional homogeneity (local connectivity) for each voxel.
• Correlation analyses were performed between regional homogeneity, lesion load, and disability scores (EDSS, ataxia).

Main Results:

• Patients with MS exhibited decreased regional homogeneity in the superior cerebellar hemispheres (lobules V and VI) compared to controls.
• A trend for reduced homogeneity was observed in the right cerebellar hemisphere.
• Reduced cerebellar homogeneity correlated with higher lesion load in cerebellar peduncles and increased global disability and ataxia scores.

Conclusions:

• MS leads to a disintegration of regional processing in the cerebellum, suggesting disrupted cortico-ponto-cerebellar and spino-cerebellar pathways.
• Impaired cerebellar functional integration is linked to general disability and ataxia in MS patients.
• Local connectivity changes in the cerebellum are a significant marker of MS-related neurological deficits.