Correlation between thalamic volume and cognitive function in patients with multiple sclerosis

Multiple Sclerosis (MS) is an chronic inflammatory and neurodegenerative disease which affects both gray and white matter, and characterized by inflammation, demyelination, axonal loss and gliosis of the central nervous system, also it presents with different clinical courses and neurologic signs. In two third of the MS patients the age of onset is between 20-40 years. The male / female ratio is 2-3 / 1. Although it is not known with certainty about the etiology, is thought to be involved in the pathogenesis of autoimmune mechanisms triggered by genetic and environmental process. Histopathologically while the axons are partially protected, demyelination, inflammation is dominated by the pathological process leading to oligodendrocyte loss and gliosis. In recent studies the direct damage of activated microglia were identified as well as tract-specific patterns in normal working white and gray matter and with the release of mediators such as cytokines, nitrite oxide from Th1 TH17 and activated microglia in the inflammation area, Thalamus, is an important structure in reciprocal communication between cortical and subcortical areas. Which anterior and dorsomedial nuclei are affected in MS patients are closely related to cognitive impairment. The rate of cognitive impairment seen in 35-60% of MS patients, and especially attention, memory and executive functions are effected. 36 patients and 23 healthy subjects were enrolled in the study in Dumlupınar University Faculty of Medicine, Evliya Celebi Education and Research Hospital Neurology Department, whom had MR imagines in the last 3 months, and had been diagnosed with RRMS according to the revised 2010 McDonald criteria, between 20-50 years of age. The patients whom had secondary causes and depression linked with cognitive dysfunction, and acute relapse history in the last 3 months and/or high dose intravenous corticosteroid therapy were excluded from the study. Control group was consisted of 23 subjects whom admitted to the neurology clinic because of headache in the last 3 months with normal neurological examination and MRI also with normal cognitive function. Neuropsychometric test was performed to the patient and control groups, for the memory, executive functions, attention language, and visuospatial area. The mean disease duration of MS patients were 2 years and the average EDSS'S were 2. Compared with the control group, in accordance with the literature in the early stages of RRMS patients attention, memory and executive functions were significantly affected. This impairment was correlated with the decrease of the thalamic area, and the corpus callosum area, and also correlated with the increase in width of the ventricles. In patients whom had low cognitive reserve that means with a training period less than 8 years, all cognitive domains were affected than those with high cognitive reserve. Our study aims to highlight the importance of evaluating the cognitive impairment by imaging methods to assess the prevention of deep gray matter in the future in the early stage of the disease.