Global and Domain-Specific Cognitive Impairment in Multiple Sclerosis Patients Based on CANTAB (Cambridge Neuropsychological Test Automated Battery) and Associated with Plasma Vitamin D Level

Abstract

Multiple sclerosis (MS) is a demyelinating inflammatory disease of the central nervous system in which the myelin around the axon damages and disrupts nerve conduction, leading to a wide range of symptoms including limb weakness, sensory symptoms, double vision, ataxia, sphincter disorders, depression and spasms, cognitive disorders are common and debilitating symptoms of this disease, which have a significant impact on the quality of life of patients. Due to the fact that very limited studies have investigated the cognitive impairment of multiple sclerosis patients and its relationship with plasma vitamin D level, in this study we intend to investigate the global cognitive impairment and the specific cognitive domains of multiple sclerosis patients based on the CANTAB test and its relationship with Plasma vitamin D level. Method: In this cross-sectional study, 124 multiple sclerosis patients were included. Patients with neurological disorders other than MS, history of corticosteroid pulse, disease recurrence in less than 4 months, alcohol or drug use, pregnancy, etc., were excluded from the study. First, the questionnaires related to the demographic information of the patients were completed and then the laboratory level of vitamin D was evaluated. SPSS software version 27 was used for statistical evaluation. Results: In summary, among 124 MS patients, 49 patients had cognitive impairment and 75 patients were cognitively intact. The average age of the patients was 31 years old, and 112 patients (90.3%) had RRMS phenotype. The level of vitamin D was less than 30 ng/ml in 30 patients (24.3%), and no significant difference was observed between the serum levels of vitamin D in patients with and without cognitive impairment (p-value=0.07). The prevalence of PMS phenotype was higher in patients with cognitive impairment and this difference was statistically significant (p-value=0.04). Spatial Working Memory (SWM) subtest was the most impaired subtest among MS patients (89.8% of patients with cognitive impairment). The logistic regression showed that, age and level of education affects the cognitive function of patients, but the level of vitamin D had no effects on the cognitive function of MS patients.