Lesion load may predict long-term cognitive dysfunction in multiple sclerosis patients

Area of Science:

• Neuroimaging
• Neurology
• Cognitive Science

Background:

• Magnetic Resonance Imaging (MRI) has provided insights into cognitive impairment (CIm) in Multiple Sclerosis (MS).
• Understanding the predictors of long-term CIm is crucial for managing MS patients.

Purpose of the Study:

• To determine the predictive role of white matter (WM) and gray matter (GM) integrity on long-term cognitive function in a cohort of MS patients.
• To assess the relationship between baseline MRI parameters and cognitive performance over a nine-year period.

Main Methods:

• A cohort of 303 MS patients from a previous MRI study were followed up.
• Baseline MRI parameters including cerebrospinal fluid fraction (CSF-f), WM fraction (WM-f), GM fraction (GM-f), and abnormal WM fraction (AWM-f) were quantified.
• Cognitive status was assessed after nine years using SDMT, SRWL (immediate and delayed recall), MCST (categories, perseverative and non-perseverative errors), and PASAT.

Main Results:

• Abnormal white matter fraction (AWM-f) was a significant predictor of impaired performance in SDMT, PASAT, SRWL (immediate and delayed recall), and MCST (categories, perseverative and non-perseverative errors) nine years later.
• Higher AWM-f at baseline was associated with worse cognitive outcomes across multiple tests.
• The predictive value of AWM-f was statistically significant for all tested cognitive domains.

Conclusions:

• Focal white matter damage, quantified by AWM-f, is the most significant predictor of long-term cognitive outcomes in patients with Multiple Sclerosis.
• MRI-based assessment of white matter lesions is valuable for predicting the trajectory of cognitive impairment in MS.
• These findings underscore the importance of monitoring white matter integrity for managing cognitive health in MS.