Cognitive Imapirment in Multiple Sclerosis: Relation to Dysability, Duration and Type of Disease

BACKGROUND: Cognitive dysfunctions are often presented as a symptom in multiple sclerosis which is associated with both structural and functional imapirments of neuronal networks in the brain. OBJECTIVE: The aim of the study was to evaluate the influence of dysability, duration and type of disesase on cognitive functions in multiple sclerosis patients. METHODS: This study included 60 MS patients treated at the Department of Neurology, Clinical Center University of Sarajevo. Inclusion criteria were clinically definite diagnosis of multiple sclerosis, 18 years of age or older and were able to give written informed consent. Cognitive function was evaluated by the Montreal Cognitive Assessment (MoCa) screening test. Mann-Whitney and Kruskal-Wallis test were used for comparisons between clinical characteristics and MoCa test scores. RESULTS: Out of 63.33% of patients had EDSS <=4.5. Disease lasted longer than 10 years in 30% of patients. 80% had relapsing-remitting MS and 20% had secondary progressive MS. 84,2 % of patients with EDSS ≤ 4.5 had cognitive dysfunction. Higher disability (rho=0,306, p<0,05), progressive type of disease (rho=0,377, p< 0,01) and longer disease duration (rho=0,282, p<0,05) were associated with worse overall cognitive functions. Level of disability showed statistical significant correlation with the executive functions and language domains of cognition (p<0.01). Longer disease duration was significant correlated with executive functions (p<0,01) and language domains (p<0,01), while progressive type of disease was signifacant correlated only with executive functions domain (p<0,01). MoCa score variables did not show a statistically significant difference in relation to the number of relapses per year and the use of imunoterapy. Statistically significant negative correlation was obtained between executive functions domain and level of disability, disease duration and progressive type of disease, while language domain significantly correlated only with disability level and progressive type of disease. CONCLUSION: High percentage of MS patients has cognitive impairment. Patients with higher disability were presented with lower cognitive abilities, especially in executive functions and language domains. Higher frequency of cognitive impairment were presented in progessive forms of disaese and longer disease duration with strong influence on executive functions domains of cognition.