Correlation of MRI findings and cognitive function in multiple sclerosis patients using montreal cognitive assessment test

BACKGROUND Magnetic resonance imaging (MRI) has improved the diagnosis and management of patients with multiple sclerosis (MS). Montreal Cognitive Assessment (MoCA) is a brief, sensitive test that has been recommended by National Institute of Neurological Diseases and Stroke and Canadian Stroke Network (NINDS-CSN) as a reliable tool to detect mild cognitive impairments. This study aimed to evaluate the relationship between MoCA test and its sub-items with brain abnormalities in MRI of MS patients. METHODS Based on MRI scans of 46 MS patients, third ventricle and white matter lesions volumes were measured. Disease duration and expanded disability status scale (EDSS) were recorded in each patient. In addition, cognitive domains of the patients were evaluated by Montreal cognitive assessment (MoCA) test. We analyzed data using t-test or Mann-Whitney U test, Pearson correlation coefficient, and non-parametric Spearman test. Furthermore, multiple linear regression model was applied to evaluate the association between cognitive indices and MRI characteristics. RESULTS Among MRI indices, only severity of atrophy showed a significant difference between cognitively impaired and cognitively preserved patients. Third ventricular volume was significantly correlated with total MoCA score (p=0.003, r=-0.42), but none of the juxtacortical or periventricular lesions volume revealed significant relation with total MoCA score. However, using multivariate linear regression after adjustment for educational level and disease duration, there was a significant negative association between juxtacortical lesions volume and total MoCA score as well as naming and attention sub-items. Also, memory score was adversely associated with the third ventricular volume (p=0.03, r=0.31). CONCLUSION Cognitive disturbances detected by MoCA, may be associated with some pathological changes including atrophy, third ventricular volume, and juxtacortical lesion. MoCA, as a brief test, is not correlated with brain lesions volume in MS patients.