Insulin Resistance is Related with Cognition Impairment in Multiple Sclerosis Patients

Abstract

Multiple sclerosis (MS) is a chronic and progressive autoimmune disease of the central nervous system (CNS). Slowed cognitive processing speed and episodic memory decline are the most common cognitive deficits in MS, with additional difficulties in executive function, verbal fluency, and visuospatial analysis. The aim of this study was to compare the cognitive status of MS patients with and non- insulin resistant. In a cross-sectional study, 74 patients with diagnosis of relapsing remitting MS were invited to collaborate. After obtaining informed consent and recording information including time of diagnosis, waist circumference, height and weight, 5 cc of fasting blood samples were taken from patients. And blood glucose and insulin levels were measured. Cognitive status of patients was assessed using Minimal Assessment of Cognitive Function in MS (MACFIMS) questionnaire. According to Homeostatic Model Assessment of Insulin Resistance (HOMA) index more than 2.5, patients were divided into two groups with (n=28) and non-insulin resistance (n=46), then cognitive status was compared in two groups. The mean of age, duration of disease and EDSS of all participants were 40.78 ± 5.2 years, 11.56± 4.56 years and 1.68 ± 1.12 respectively. In our study, the prevalence of insulin resistance was found 37.8%. The mean scores of CVLT, CVLT-DR, COWAT, JLO tests were significantly lower in the insulin resistance group comparing to non-insulin resistance group (P<0.05). Also, the score of the CVLT, CVLT-DR, COWAT, JLO, BVMT and DKEFS tests had reverse correlation with fasting insulin levels, which was meaningful for COWAT. MS patients with insulin resistance are more disturbed in the areas of verbal memory, verbal fluency, executive function and visuospatial processing and this disorder is exacerbated by an increase in fasting blood insulin levels.