Evolution of Cortical Lesions and Function-Specific Cognitive Decline in People With Multiple Sclerosis

Area of Science:

• Neuroscience
• Neurology
• Radiology

Background:

• Cortical lesions in multiple sclerosis (MS) significantly impact cognition, but their long-term evolution and specific effects on cognitive functions are not well understood.
• Understanding the relationship between cortical lesion progression and cognitive decline is crucial for managing MS progression.

Purpose of the Study:

• To investigate the 10-year evolution of function-specific cognitive functioning in people with MS.
• To assess how cortical lesion load and formation influence cognitive trajectories over time in MS patients.

Main Methods:

• Prospective study with 3T MRI (T1, FLAIR) and neuropsychological assessments over 10 years (2008-2022).
• Evaluated 7 cognitive functions: attention, executive functioning (EF), information processing speed (IPS), verbal fluency, and verbal, visuospatial, and working memory.
• Cortical lesions identified manually; linear mixed models used to analyze lesion load and cognitive decline, stratified by MS disease stage.

Main Results:

• 223 people with MS and 62 controls included; 94 MS patients completed 10-year follow-up.
• MS patients showed baseline deficits in IPS and working memory; over 10 years, attention, verbal memory, and EF declined most.
• Baseline cortical lesions correlated with attention and verbal fluency decline; lesion increase (especially in late/progressive MS) correlated with verbal fluency decline.

Conclusions:

• Cognition in MS deteriorates over a decade, impacting attention, verbal memory, and EF, with baseline IPS and working memory impairments persisting.
• Cortical lesion load and formation are associated with cognitive decline, extending impairments to functions initially less affected.
• Accumulating cortical damage in MS leads to a broader spread of cognitive deficits over time.