Cognitive Impairment and Magnetic Resonance Disease Activity in Multiple Sclerosis

Background: Multiple sclerosis (MS) can intermittently lead to the presence active inflammatory lesions, which acutely interrupt white matter tracts between different parts of the brain, resulting in impaired cognition and memory.

Objectives: MS patients will be more cognitively impaired when assessed during a time point with which they have acute contrast-enhancing lesions on MRI as compared to when they have no contrast enhancing lesions.

Methods:

75 MS patients underwent a comprehensive cognitive battery at month 0, 6, 12, and 24. Brain MRI with contrast was performed monthly. Cognitive domains assessed included attention/information processing speed, visual-spatial/executive function and verbal memory/attention span. MRI scans at the time of cognitive testing were characterized as active vs. inactive based upon presence or absence of Gadolinium-enhancing lesions.

Results:

162 MRI scans were associated with patients with abnormal cognitive tests, and 89 MRI scans were associated with who had normal cognitive function. 83 MRI scans with Gadolinium-enhancing lesions, or ‘active’ scans, were associated with abnormal cognitive function, and 79 ‘inactive’ MRI scans were associated with cognitively intact individuals. Thus, MRI scans with active lesions were not more likely to be associated with cognitive dysfunction (p=0.8). Even when comparing only those with severe cognitive impairment within a single domain vs. normal cognitive function, no association of brain MRI activity to cognitive dysfunction was observed (p=0.6).

Conclusions:

Patients with MS were not more likely to have cognitive dysfunction when assessed around the time of active MS lesions as detected on MRI. Additional analyses will be performed in the future to better assess and compare cognitive performance with the volume of acute lesion activity and changes over time.