COGNITIVE IMPAIRMENT IN MULTIPLE SCLEROSIS: ASSOCIATION WITH THE ACTIVITY OF INFLAMMATORY PROCESS AND SEVERITY OF DISABILITY

Abstract

Background: Multiple sclerosis is the most common neurological disease leading to disability in young and productive patients. One of available methods of control over the course of the disease and detection of its progression is neuropsychological testing. However, selection of the most informative tests, as well as the search for interpretation of their results is still ongoing. Aim: To study cognitive functions in multiple sclerosis patients depending on the disease activity and degree of disability. Materials and methods: Fifty patients with multiple sclerosis were evaluated during their remissions and 15 of them were additionally assessed during an exacerbation. During neuropsychological testing a computer test “Selection of figures” was used for assessment of attention, productivity, frontal functions and visual neglect. We studied potential dependency of the parameters obtained from degree of disability and disease stage (exacerbation or remission). The control group comprised 12 healthy subjects. Results: Compared to healthy subjects, the multiple sclerosis patients had a prolonged time of test performance, decreased learning, and statistically significant decrease of the working efficacy (p < 0.05). During an attack, there was a decreased conceptualization (48 answers compared to 51.5 at remission stage); more than 3-fold (from 1,3 to 4,4) increase in the number of figures missed in one visual field, that could indirectly indicate visual neglect. Also, changes in frontal functions were noted as a tendency to almost 2-fold higher numbers of perseverative answers, more frequent categorical escape and learning abnormality. There was a positive correlation between expanded disability scale score (EDSS) and working efficacy (r = 0.453, p = 0.001), and a negative correlation between EDSS and mental stability (r = 0.4055, p = 0.0035). Conclusion: Patients with multiple sclerosis had abnormal rate and accuracy of test performance, compared to those in healthy subjects. During an exacerbation of the disease, there was a deterioration of the parameters compared to those registered in the remission. Also, a negative association with disease severity assessed by EDSS, was found. The data obtained documents feasibility of the computer test “Selection of figures” for dynamic control in multiple sclerosis patients.