Brain atrophy and lesion load as explaining parameters for cognitive impairment in multiple sclerosis

Area of Science:

• Neuroscience
• Neurology
• Radiology

Background:

• Multiple sclerosis (MS) is a central nervous system demyelinating disease.
• Cognitive impairment is a significant manifestation of MS with substantial social impact.

Purpose of the Study:

• To investigate the relationship between structural brain damage (lesion load and atrophy) and cognitive impairment in MS patients.
• To assess the influence of lesion distribution and confounders like fatigue, pain, and depression on cognitive performance.

Main Methods:

• Magnetic resonance imaging (MRI) was used to quantify T2 and T1 lesion load and whole brain volume in 82 MS patients.
• Cognitive function was assessed using the Brief Repeatable Battery (BRB), with impairment defined as over two abnormal tests.
• Statistical analysis examined correlations between lesion load, atrophy, and cognitive test scores, controlling for fatigue, pain, and depression.

Main Results:

• Cognitive impairment was observed in 67% of MS patients.
• Moderate correlations were found between specific cognitive tests and regional brain lesion loads (frontal, parietal, temporal) and atrophy.
• Brain atrophy and lesion load were the primary determinants of cognitive test scores, explaining 10-25% of the variance, and were more influential than fatigue, pain, or depression.

Conclusions:

• Cognitive impairment in MS is moderately associated with the amount and spatial distribution of structural brain damage.
• Structural brain changes, particularly atrophy and lesion load, are key factors influencing cognitive performance in MS patients.
• The findings highlight the importance of considering brain structural integrity when evaluating cognitive deficits in multiple sclerosis.