Determination of the relation between cognitive functions and depression, fatigue, disability in individuals with multiple sclerosis

ABSTRACT DETERMINATION OF THE RELATION BETWEEN COGNITIVE FUNCTIONS AND DEPRESSION, FATIGUE, DISABILITY IN INDIVIDUALS WITH MULTIPLE SCLEROSIS Pınar YİĞİT, Deparment of Physiology, Health Science Institute, Dokuz Eylul University, İnciraltı/İZMİR Objective: Multiple sclerosis (MS) is a cronic, progressive and neurodegenerative central nervous system disorder. MS, usually, causes disability, cognitive deficiency, fatigue and depression symptoms. The aim of our study is to assess cognitive functions of people with MS and investigate the impact of depression, fatigue and disability on the cognitive functions. Method: 200 patients, who have been diagnosed with MS and followed up at the MS Clinic of Dokuz Eylul University Neurology Department and matching the criteria of the study, were included in our study. Participants in the study were consisted of 140 females and 60 males, (mean age: 36.53±9.73, mean education level: 11.98±12.50). All participants' cognitive assesment have been evaluated with Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS) battery, which includes the Symbol Digit Modalities Test (SDMT), the California Verbal Learning Test-2 (CVLT-II) and the Brief Visuospatial Memory Test-Revised (BVMT-R). Expanded Disability Status Scale (EDSS) was used to evaluate disability levels. Fatigue Severity Scale (FSS) and Beck Depression Inventory (BDI) were used respectively, for fatigue level and depression level. The relation between cognitive functions and depression, fatigue, disability were examined with independent samples t-test and chi-square test. Findings: BICAMS score have been found to be positively correlated with the age, negatively correlated with the education level. The female MS patients scored significantly higher in verbal memory scores (CVLT-II) than males. We found no relationship between BICAMS scores, disease duration and depression level. However, EDSS scores and BDI scores were significantly higher in those with a disease duration of 5 years or more. FSS positively correlated with EDSS and BDI, also negatively correlated with SDMT and BVMT-R. Those with EDSS score of ''4 and above '' were found to have lower BICAMS performances but higher FSS scores. There was a significant difference in SDMT performances between the groups with and without fatigue (FSS≥4 and FSS <4 respectively). When depression and fatique symptoms concurs or in the existence of just one of them or none of them, significant differences in terms of SDMT performances have been shown. Result: In conclusion, the level of disability and fatigue were adversely affected on the cognitive functions of people with MS, depression has no significant effect. In MS individuals, there is a need for longitudinal studies with more MS population due to the factors', such as depression, fatigue and disability, potential to overlap each other. BICAMS which is spesific for MS, is a reliable, sensitive, which is easily performed in clinical practice, can be beneficial to assess cognitive state of people with MS and to follow up the effect of the therapeutic interventions. Key words: Multiple sclerosis, cognitive funtions, disability, depression, fatigue.