Background: Multiple sclerosis (MS) is an autoimmune disease of the central nervous system manifested by a wide range of motor, sensory, and Cognitive Impairments (CI). The clinical features and mechanisms underlying CI in MS are currently being actively investigated.

Objective: To examine the relationship between neuropsychological test performance and the extent of white matter damage in the cerebral lobes using voxel-based morphometry.

Materials and Methods: The study included 33 patients with MS in the relapse phase. MRI and neuropsychological assessment were performed before pulse therapy. The mean age of the patients was 37 years (SD = 11.4), and 60.6% were female. The neuropsychological assessment included the MoCA, Brief Visuospatial Memory Test-Revised (BVMT-R), Stroop test, category fluency test, and Free and Cued Selective Reminding Test (FCSRT). According to DSM-5 criteria, 27.3% of patients had mild neurocognitive disorder, and 9.1% had dementia, which is significantly more frequent than in the general population of the same age group.

Results: Total brain lesion volume significantly correlated with the first (rho = -0.409; p = 0.022) and fourth (rho = -0.389; p = 0.031) recall trials of the BVMT-R. Right parietal lobe lesion volume was significantly associated with impaired visuospatial memory on the delayed BVMT-R recall 25 minutes after encoding (rho = -0.37; p = 0.044). Left parietal lobe lesion volume was significantly associated with reduced verbal fluency on the letter fluency test (rho = -0.373; p = 0.043). Right temporal lobe lesion volume correlated with sentence repetition performance (rho = -0.372; p = 0.043). According to VLSM analysis, lesions of the left superior longitudinal fasciculus and the left inferior fronto-occipital fasciculus were associated with lower scores on cued recall after 5 minutes in the FCSRT.

Conclusions: According to the obtained data, cognitive impairment is significantly more frequent in patients with MS than in the general population. The severity and pattern of the detected impairments do not depend on the total lesion volume, but rather are associated with the specific localization of lesions. Therefore, timely initiation of disease-modifying therapies for multiple sclerosis is the basis for prevention of cognitive decline.

Vladislav V. Griniuk, is an Associate Professor in the Department of Nervous System Diseases at the N.V. Sklifosovsky Institute of Clinical Medicine, I.M. Sechenov First Moscow State Medical University (Sechenov University), Ministry of Health of the Russian Federation, Moscow, Russia. He is a distinguished academic and medical professional specializing in nervous system diseases and contributes to clinical practice, medical education, and research in the field of neurology.