Magnetic Resonance Imaging to Detect Brain Damage in Patients With Multiple Sclerosis

OBJECTIVE: The study will evaluate cognitive impairment in patients with multiple sclerosis (MS) and correlate the degree of cognitive dysfunction as identified by scores obtained in multiple cognitive tests with measurements of cortical thickness, cortical lesions and white matter disease on magnetic resonance imaging of brains of MS individuals. STUDY POPULATION: Study population will consist of 49 patients with relapsing remitting or secondary progressive MS with superimposed relapses who have been treated with Interferon beta at fully tolerated dosages for at least six months, and 49 healthy volunteers matched for gender, age and educational level. We expect to screen 65 individuals per arm in order to be able to enroll 49 individuals per arm, thus meeting the requirements of the sample size calculations. DESIGN: After screening clinical (rating disability by the means of the Expanded Disability Status Scale \[EDSS\] score), neurophysiological (e.g. evoked potential tests) and imaging examinations, MS patients and healthy subjects will undergo a neuropsychological evaluation using the Minimal Assessment of Cognitive Function in Multiple Sclerosis (MACFIMS) and the Automated Neuropsychological Assessment Metrics (ANAM), and also a 3 Tesla magnetic resonance imaging (MRI). After 25% and after 50% of projected patients have been enrolled, distribution in MACFIMS will be evaluated to ensure that a broad spectrum of cognitive ability is represented. Cortical thickness, cortical lesions and white matter damage metrics (e.g. lesion load, diffusion tensor and magnetization transfer MRI measures) will be computed. In order to exclude the hypothesis that the presence of fatigue, anxiety and depression, normally occurring in MS patients, might interfere with their cognitive performance, thus acting as confounding factors, scales measuring fatigue and mental status will be administered in all subjects. Scores obtained on these scales will be used as covariates in each of the statistical analyses performed in the present study to account for their possible effects. OUTCOME MEASURES: The first outcome measure will be the MACFIMS and cortical thickness values. Correlation between these two metrics will be initially performed. Secondly, cortical lesions as well as white matter lesions on T1 and T2 weighted images, magnetization transfer ratios and diffusion tensor imaging metrics of lesional and normal appearing brain tissues will be computed and their impact in determining cognitive impairment will be determined. Thirdly, deep gray matter, white matter and total brain volume measures will be computed and correlated with cognitive function measured by the MACFIMS. Similarly, correlations between clinical disability, as measured by the EDSS score and cognitive impairment, as well as between EDSS score and each of the RMI variables explored in the study will be performed. Finally, the level of correlation between MACFIMS and ANAM tests will be investigated.