Characteristics of cognitive impairment in multiple sclerosis patients depending on different risk factors

Abstract

Cognitive impairment (CI), along with motor deficit, is a crucial component of a disability aggravation in multiple sclerosis (MS) patients. The aim of this study was to asses characteristics of CI in separate cognitive domains depending on socio-demographic (age, sex, level of education), disease parameters (severity, course type and disease duration) and external factors (smoking). The current study enrolled 137 MS patients (102 women and 35 men) aged from 22 to 69 years. All participants were divided into two groups depending on the disease course: group А – patients with relapsing-remitting (RR-MS) type (n=106) and group B – participants with progressive forms of the disease (n=31). The following study discovered that disruption of separate cognitive domains was present even without the apparent CI according to MоCA (Montreal Cognitive Assessment): executive functions impairment (p=0,0013) was found most frequently in case of RR-MS, and memory (p=0,0233) decline in case of progressive forms. In the group A moderate CI were associated with decrease of memory (p<0,0001), attention (p=0,0061), executive functions (p=0,0005), language (p=0,0080) and abstract thinking (p=0,0018); severe CI – with disorders of attention (p=0,0055), language (p<0,0001) and abstract thinking (p=0,0144). As for the group B, moderate CI were associated with decline of abstract thinking (p<0,0001), and severe CI – with impairment of memory and executive functions (p=0,0337). Level of physical disability and smoking impact CI independently of MS course, meanwhile, presence of higher education proves to be beneficial for preserving cognitive functions. In addition, disease duration, number of exacerbations and male gender (concerning attention decline) can affect cognition in relapsing-remitting course of MS.