Cognitive impairment in multiple sclerosis – a review of current knowledge and recent research

Abstract

<jats:title>Abstract</jats:title><jats:p>Multiple sclerosis (MS) is a chronic, progressive disease of the central nervous system that is characterised by inflammatory damage to the myelin sheath. Though often neglected, cognitive impairment is a common feature of MS that affects 43–70% of patients. It has a sophisticated neuroanatomic and pathophysiologic background and disturbs such vital cognitive domains as speed of information processing, memory, attention, executive functions and visual perceptual functions. In recent years there has been growing interest in neuroimaging findings with regard to cognitive impairment in MS. The possible options of managing cognitive dysfunction in MS are pharmacologic interventions, cognitive rehabilitation and exercise training; however, not enough evidence has been presented in this field. The aim of our article is to provide current knowledge on cognitive impairment in MS based on the most recent scientific results and conclusions with regard to affected cognitive domains, neuropsychological assessment, underlying mechanisms of this disturbance, neuroimaging findings and therapeutic options.</jats:p>

Cognitive impairment as one of the important non‐motor symptoms in multiple sclerosis and neuromyelitis optica spectrum disorders

“…The reason for this wide range of the prevalence could be due to variations in the clinical backgrounds of patients, including clinical phenotypes and duration of the disease, and the batteries used to evaluate cognitive function. 9 Information processing, which is often considered the main aspect of cognition affected, in patients with MS is composed of several steps, starting with the input of information into the sensorial system and extending to the output (action or behavior). 3,8 The prevalence of cognitive impairment in MS was reported in divided domains, and information processing speed, memory, attention, executive functions and visual perceptual functions are 20-50%, 33-65%, 12-25%, 17-19% and up to 25% in MS, respectively.…”

“…Three major steps are required to complete this process entirely: (i) the transmission of sensorial information; (ii) the completion of cognitive tasks; and/or (iii) creating motor output. 9 Attention refers to a sophisticated cognitive function, which links different processes, such as alertness and vigilance. 10 While processing speed is often considered the core affected aspect of cognition, patients with MS also suffer from deficits in memory, language, working memory and executive functioning.…”

“…10 Each of these processes must take place very quickly in order to successfully accomplish the task with time demands, which is the information processing speed. 9 However, independent assessment of attention is difficult, and this cognitive domain is strongly connected with other cognitive domains, such as information processing speed, working memory and fatigue. 3 In fact, memory impairment is one of the most common cognitive symptoms to be observed in patients with MS.…”

“…10 While processing speed is often considered the core affected aspect of cognition, patients with MS also suffer from deficits in memory, language, working memory and executive functioning. 9 Cognitive impairment has been identified in all clinical phenotypes of MS, and the severity and frequency of cognitive deficits is higher in patients with progressive-type MS than in those with relapsingremitting MS (RRMS). In the majority of those cases, long-term memory (responsible for learning and recalling abilities) and working memory are disturbed.…”

“…38 Batteries, such as the Functional Assessment of Multiple Sclerosis tests, showed that cognitive impairment was associated with lower quality of life scores. Therefore, appropriate neuropsychological tools must be used to assess cognitive function in patients with MS. 9 Given the progressive nature of the disease, instruments must be longitudinally sensitive and should ideally minimize confounders presented by other aspects of MS, such as physical disability, medication and mood. As the impact of cognitive impairment on daily activities is often misunderstood by family, friends, workmates and even health professionals, this symptom might adversely affect people close to the patients.…”